Vincent Technical Sections: -Serial Numbers/Production- Photo Gallery of Models - Brakes - Engine Overhaul - Vincent Engines - Wheels/Fenders - Instruments - Transmission - Clutch - Magneto - Tank/Seat - Suspension - Tools - Norvin - Electrics- Carburetors - Misc - Links -Vincent Parts/Services Suppliers - Polishing/Cleaning - Shipping Vincents-Electric Starter - Paint/Transfers

The Vincent Clutch  
Vincent Clutch Shoe
  Tips on how to repair, adjust, and improve.  If you have any to share, please e-mail. Thanks.


Here are some things I've learned in working on Vincents to make life easier when resealing the clutch.  After the derby's off, shake the clutch drum around a bit to check for wobble.  Time taken to do this is around 5 minutes.  That's moving the foot peg hanger out of the road, removing the screws in the derby, and shaking the clutch by hand.  If it shakes too much, you're going to have to replace PD22 and PD24.  That'll take the wobble out.  If they have to be replaced, sometimes the bushes require a quick ream to obtain a nice slide fit.  If PD22 and PD24 seem to be in good shape, remove PD24, that's the thick bush, inboard.  Heat PD20, the chain sprocket, with an acetylene torch, and PD22 will drop out of it's sprocket bore.  You don't have to bother with PD22.  The reason you remove the PD24 bush, is because that's the inboard side where the PD25 seal is pressed into the PD20 sprocket.  That will give you the lip on the seal pointing in the right direction to properly seal.  Remove the old seal with a light tap on the end of a screwdriver.  Now with a light coat of Never Seize, replace PD24 into PD20's bore.  If bushings had to be replaced, this job takes no more than 30 minutes.  Remove 9 screws and 1 nut to remove clutch assembly.  This takes approximately 10 minutes.  Remove clutch drum from sprocket by removing 6 screws.  Takes about 10 minutes.  Remove primary cover with a 3/8" butterfly impact.  Takes no more than 5 minutes.  Replace PD26 seal.  Takes maybe 10 minutes.  Now replace gasket PD14 and ET105.  Takes about 10 minutes to scrape, clean, and put some sticky stuff on to hold in place.    Reassemble.  Takes about 30 minutes.    Max Lambky  11-3-10
Conway's now sells a modified Honda clutch to replace the Burman clutch on your Comet.  I bought one, looks very nice but required hand filing and fitting.  We tried the splined receiver on 2 clutch shafts, so I believe the receiver was originally machined undersize for a worn Burman trans shaft.  Hard for them to know how worn your trans shaft is...and no place for a sloppy fit.  Have not road tested clutch as of 5/11/10... will report on performance later.    Jim  5/11/10   Just ordered another Conways clutch for other Comet... 7/21/10.  Other owners report excellent performance.   Here is Craig's  PDF file of Conway's clutch instructions: Test: Burman
I crunched a Shadow brake drum a month or so back - it parted circumferentially just inboard of the sprocket flange. All five sprocket bolts were in situ. No nuts were. The replacement drum boasts 7 Loctited bolts, and three Loctited dowels. As Trevor remarked, three fitted bolts are probably more than enough - but only if they remain tight.  Anon  6/16/09
Triumph Clutch: My clutch is run fully wet. There is no clutch housing in my chaincase, it was machined completely out to allow fitting of a Triumph clutch. This slipped when it didn't drag, so I bought a V3. But whether V3 clutches that are run dry, or at least damp, give problems, I wouldn't know. What I do know is that V3 clutches run fully wet, with coined (dimpled) plates replacing the original plain steel plates, are about as perfect as anyone has any right to expect.    Tom  6/16/09
V2 Clutch:  Bought a (aluminum version) V2 in 98, carefully shimmed the buckets, discovered the less the adjuster pin portruded towards the clutch plate side, the less tendency for pressure plate "tipping" on lift off so selected longest pair of clutch rods.  Soaked it initially and have run it dry since with no sticking (no matter how long stored), grabbing or standing start 1st gear engagement clash.  With light feel and progressive engagement it is absolutely faultless.  As I have yet to get a clear cut description of the "improvements"  - if any - in the V3,  have thus delayed ordering either and after careful dismantled/reassembly of the low mile Lightening plated original in this Shadow have soldered on 1,100 miles with it relatively pleased though mindful of  its foibles.   Coventry Spares still stocks V2's so at the first hiccup on this stocker, will not hesitate to order another.    Peter  6/16/09
Sealing the Clutch Splines: This  is easily  done and  none of  the sealant  is  forced  towards the chainwheel.   Been doing  it  this way  for 5 decades.   After  cleaning off the splines on the protruding shaft and in the bore of the shoe carrier -  I  use contact spray cleaner - the  Permatex 300  is applied to the inner splines  Only in the shoe carrier,  none to the shaft, using the applicator brush provided, an even coverage but  not being excessive.  One  reaches down into and within a  quarter inch of  the recess where the C18 seal will be located.   The sealent  is brushed along the inner and outer lands right on up and out,  near to the end  of  the  carrier bore .   It  is allowed a few minutes to set up,  growing  firmer.  A  light smear of  soft grease is applied  to  the outer polished  extended  portion which will  slide into the bushings and O-ring  located within the chain wheel,  this to help it enter and slide home,  protecting  the O-ring as it enters,  and also lubricate the  surface the twin bushes operate against.  Now and carefully the shoe carrier assembly is lined up with the splines and pushed into the chainwheel - going fully home.   That's all the sealant required to prevent oil  migrating down the shaft.   I  use it on the drum screw threads too.   No seepage or ever coming loose, yet allows  removal when needed.  Permatex 300 - now  produced  I  believe by Loctite Corp comes in  a small white plastic tub.  It dries to the consistancy of  tar,  not   really hard,  so endures well in this location and will allow  removal later on.  It's  extremely good at resisting lubricants and fuel thus is perfect on fuel taps screwed into  gas tanks, and does perfectly on all joints and covers - requiring only a light coat.   And it  stays  put  unlike RTV products which have destroyed so many motors. Sid    6/16/09
The Works method for testing general
clutch function is simple and most know it.  djust the clutch cable to close limits by the book.  With the bikeon it's center stand select 4th gear and  fully lift the clutch lever.  With the free hand one spins the rear wheel.   It should spin quite freely - nearly as if in neutral.  Sometimes it will need being rocked back and  forth to free off the bits - but that's the test for the centralizer plungers correct function,  i.e.  they retract the shoes off the drums face.  The accepted gap between the highest spots on the shoe segments and the drums rubbing surface is .025 - .028".   Might well be a  bit more with high mileage components.  This serves to permit  the natural drum wobble at idle and during  shifts, eliminating  contact with the shoes.  Keep in mind that even at it's best there will be lapses in consistancy due to a buildup of  dust,  high heat and dry joints.   But it can still be amazingly competent and satisfying,  very durable and able to  transmit  impressive torque.   Far better than any other British clutch offered during  it's manufacture.   Sid   6/16/09

Oil Leaks: Both the splines on the shaft and inside the shoe carrier must be clean and oil free before applying  the sealant - and  I've  used  Permatex AC Super 300 for decades with good results.  Oil  must pass along this shaft toeven reach the metal /rubber seal  ring.  Sid  6/15/09

Years ago Charlie Taylor showed me a trick. Since the clutch seal (C18/1) on a Vin is close to worthless, he'd take the unit apart,  clean the end real good and then squirt some silicon seal around the end of the carrier C-3 and C20 (where the seal is suppose to be). Reassemble the clutch, tighten everything up and let it sit (or set) for 24 hours.  I've done this on two Vins and it worked fine.  Somer  6/14/09

Clutch: Oil on the shoe segments is devilish to completely remove due to their porus nature.  Upon  reheating  and being spun round at speed the slippery stuff  gets flung outward onto the surface to once again cause slippage.  Reseal the shaft splines and replace the center seal,  also a bit of  Permatex on the drum screw  threads a wise idea.   Oil entry cannot  be tolerated.   Be  sure  to maintain the chaincase oil  level - never allowed to rise above above this. Overtighting the centralizer springs affects shoe engagement,  and is critical only on a drag racer where it assists high rev shifts, actually  needing  only  to be a firm  thumb squeeze giving  a  nice deep travel of the plungers on a street bike.  More can be a  problem..   Condition of  the springs is important as is the fit of the thimbels in their bore.  Nice and  free yet not wobbly like a drunk.  If  firm contact pressure with the pin is in doubt  this must be dealt with.   If  ones outer plate springs are old and sacked out, the  lever pull  feeling extremely soft - this Will cause slippage beginning above 50 mph when the throttle is rolled on.  Replace with fresh springs,  and as a temp fix until you do - drop a  washer maybe two into each of  the cups {these washers ground to fit } so to compress the springs a bit. Guard against their becoming coilbound  though  Sid  6/12/09
Balance Shoes: To help release the clutch at high RPM - balance the shoes about the pivot pin. This can mean drillings on the long side and adding weight to the short side. Made a big difference to the original clutch in the Woolly which had a hard time disengaging  when shifting first to second at anything past about 40 mph.  Robert  Watson 3/7/09
Grabby Clutch:  You can rough up the Lightning-style friction disk, and flatten and scratch up the clutch plates and still have a grabby clutch.  You can make sure the plungers are situated correctly relative to the pins, i.e. touching them when fully released, and still have a grabby clutch.  Sometimes you can feel two distinct phases to the clutch engaging.  First you can feel the plate part of the clutch engaging, then as you let the lever out a little more, you get the snapping-on effect as the leading shoe engages abruptly.  You can also notice that sometimes after hard acceleration in first, the clutch doesn't seem to want to disengage for that quick shift into second.  I've concluded that there are only three more deficiencies that could cause this.  First, looseness between the pins on the clutch shoe carrier and the holes in the shoes.  Second, bad, broken, or too loosely adjusted plunger springs .  Third, worn bushing in the clutch plate carrier.  In my case, it could be all three, but most likely the springs.  You can try flattening and roughing up the plates and disk first, since you don't have to take the clutch completely apart to do so.  You can also try to slip a thin screwdriver blade between the plunger and the pin on the plate carrier, and try to divine whether or not there is enough spring in the plunger springs.  You can make sure the 9 clutch springs all are equally springy, and the plate lifts cleanly (there are only about 43000 possible arrangements for the springs).  A special Bewley-made top-hat thingy for the end of the clutch rod(s) helps tremendously.  If all that doesn't work, you'll have break that oil seal between the shaft, carrier, and nut that you've miraculously managed to establish all those many years ago, take the clutch completely apart, and fix things.  After fixing, you can start stuffing RTV, chopped up old rubber bands, condoms, cigar butts, along with a C18, back into the shaft, shoe carrier, and nut, and hope you can reestablish that oil-proof seal.  Then, you can realize that sometimes the inner and outer plunger springs bind up as they are tightened and break, at which point you can take it all apart again.  It goes without saying, that you've made sure the shoes are installed the right way around.  Tom  3/7/09
I had a lot of trouble with the clutch on my Shadow, slipping. I tried boiling the shoes in detergent but that did not help.  Finally diagnosed to the need for new shoe linings, which were unobtainable at the time, so I obtained a multi-plate clutch from Russel Kemp.  Very nice unit. I had to relieve the splines a bit to get it to slide on easily, and got 3 stronger springs for a bit more feed-back at the lever.  The big problem was its grabbyness. You could really kangaroo with it. Sanding and oiling the plates were giving only temporary remedy. Tht works by reducing the  friction content of the cluster.  So my solution, which has been tested on The Lap Of The IOM and up and down the country 2 up with luggage, is to swap a pair of adjacent plates in the cluster. This has the same effect as removing them, without reducing the spring compression.  Ernie Lowinger  7/23/08
V3 Clutch:  We use one in the Vincati and after some trial and error have it now behaving perfectly,  the equal of any modern machines.   As suggested  we originally  fitted the dome with a level / filler plug and a drain plug ---  but  didn't use it.   This just had the plates edges  dipping into the fluid.   Now it runs in the   Mobil  1 Synth ATF I use in the  primary case, connected  via a single  drilled  hole { thus easily tapped and plugged off  if need be }  located at the normal operating case level, ie -  inline with the existing level  hole.  This comes through behind the  plates.   When I fill the case I tip the bike slightly to the left to fill the dome to its shallow depth, then tip the bike back upright again and bring the maincase level  back up to normal .    This seems all the clutch needs, damp but not  drenched and able to spin the fluid off  while  running  fast to eliminate any slippage,   while at idle and slow speeds she re-wets and cools.   No wear seen or signs of heat.  We do suck out this fluid and replenish once in a while to keep it fresher in  the main case  using a suction  pump.  Note that our left side  mainshaft has a double lip seal  between the bearings to eliminate  transfer of fluids.  A  light oil  rather than the ATF should eliminate this need .   In fact  I was advised  recently   by  Neal Videan ,  maker of these clutches,  that  Mobil 10 w / 40  would be better suited for this situation.   I intend to change over to this myself  --  tho the ATF  gives  lovely  release and  clean  noiseless shifts.  The oil might be better for the chain  etc .   I use the complete Videan  primary  kit  in this motor as offered in  MPH  -  to full satisfaction.  Very quiet running mechanically.   Sid   12/11/07

V3:  About a year ago you told me about running on just three springs and I tried it on the Prince. It was very nearly there but I found that hard acceleration would produce clutch slip. I contacted Neil Videan and he supplied me with three sets of 20 pound springs. With six of these fitted I had a very light clutch but again, it was possible to induce slip with a heavy right hand, so I compromised with three heavy and three light springs and that works pefectly.  I don't have a mainshaft oil seal so I've still got engine oil in the primary. Because of this I use ATF in the clutch housing only and check it fairly frequently.  I'm running a modified G93 as has been discussed here recently which means that the hardened end of my pushrod is contained within the gearshaft and not subject to any side loads. I take a piece of ordinary 1/4 inch diameter alloy rod, what used to be HE30, now 6082 TF. I can't put my hand on the book that tells me the American equivalent spec. but it's not critical anyway. I drill and ream one end 5/32 inch diam. by about 5/16" deep. I don't cut it to length at this stage. I then put a piece of 1/4inch diam. silver steel in the lathe, face it off and break the sharp corner. About 1/8 inch back I plunge in with a 1/4 inch wide parting tool to produce a spigot to be a press fit in my reamed hole. At this point I leave it on the bar and take it out of the lathe. The reason for making this part seemingly the wrong way round is because whilst it's still attached to the length of rod it makes it easy to heat it to cherry red and quench it to give a hardened surface, but more to the point once I've cleaned the surface I can put a flame on the rod and watch the colours travel up to temper the spigot to blue. It can now be cut off and pressed into the end of the alloy rod. I can then offer it up to the bike together with the 1/4 inch roller and trim it to length before radiusing the end to fit Neil's thrust race. All three of my twins have this setup. Incidently, it pays to ensure that the outer plate of the clutch spins true with the clutch lever pulled in.  I've often found small variations between clutch springs, from all sources, not just Neils. If you get the odd spring that comes from a different batch there can be small differences in the heat treatment  and you might need to swap the positions of a couple of the springs to get the best result. Should you encounter this it can be interesting to place two seemingly identical springs end to end between the vice jaws and watch how they close up under pressure. Roy Cross  5/26/07
My Vincent has a
Neil Videan V3 clutch. It's essential to have a lever that is 1 1/8 inch from pivot to cable or you won't get enough cable movement. I run my clutch in ATF and I have an alloy pushrod with a hardened insert at one end. This avoids loss of movement with a hot engine. I found the clutch a little heavy in traffic with the original 35 pound springs and Neil kindly supplied me with some 20 pound springs. I now run with three of each very satisfactorily.  It is important to have only minimum end float in the gearbox mainshaft as you can't afford to lose clutch movment. It's also helpful to pull the clutch in and blip the engine to free the plates before selecting first. A bit more clutch movement would be nice, but not at the expense of a heavier clutch operation.  Roy Cross  5/16/07
Increasing clutch lift for multiplate clutches:  The kickstart cover's clutch arm (G91) adjusting screw has a ball at the end where it contacts the G91, the fulcrum point of the G91 lever.  Moving this fulcrum point further away from the pushrod increases the travel at the pushrod.  This is accomplished by removing the cover and replacing the adjusting screw with a short, solid, flat faced dowel pressed into the bore of the cover formerly occupied by the adjusting screw.  This bore is non threaded and larger than the 3/8" adjusting screw, I can't remember the exact size, I turned mine up to fit tightly.  The G91 will now contact the dowel at it's lowermost point (you may have to relieve the G91 a touch so it hits in this spot) instead of in the center of the cover's bore where the ball of the adjuster screw previously made contact with the G91.  Also necessary is to trim the dowel to length such that the G91 is perpendicular to the pushrod  at their contact point when the G91 is at half travel as adjustment at the cover is now eliminated.

An alternative suggestion was to simply use a flat faced screw in place of the standard adjuster.  I too thought of this but decided against it for several reasons: the leverage increase would not be as much as with the larger dowel inside, you would be putting a side thrust on the threads in the cover and the screw's threads would deform in use where they contact the G91 making removal impossible without stripping the cover.  I also thought of using a screw to push on the back of the dowel for adjustment but this takes the dowel off it's firm seating in the cover bore and would cause rocking of the short dowel.

Hope this better describes it.  Again this was not my idea but it sure works for me.  I found with my multiplate clutches the standard lift was not enough to make clean, crunch free gear engagements.   It does increase effort at the handle bar slightly, up to about half that of a Commando.  The nice part about this is no Vincent parts are harmed.  Easily reversed by replacing the dowel with the standard adjuster.    Paul Zell  5/16/07

Patent information for the Vincent Clutch:

It was Vincent's idea but Irving made it work. The first clutches were run wet, but the supplier of  oil impervious lining ceased production of the material. The  clutch cover was modified to hold the seal and the nut on the trany shaft, C20, was made in 3 pieces. They were prone to coming loose as it only had a 1/2" dia thread on it. The three springs were increased to 6 as the clutch lever was to light. The early B had a different clutch cover, C20 Nut, and a G3 shaft. It also shifted poorly so  later got a modified G32 cam plate. Dan. 1/28/07

Clutch Operation: The things that need looking at are:

Adjustment: Adjust the clutch cable when the handlebar lever is fully pulled so that the top end of G91 hits the abutment G94. Then adjust the clutch actuating pushrod with C42/1 and/or ET27/1AS so that there’s 1/4” play in the cable.

Oil leaks: The clutch needs to be completely dry. If it’s oily, check chaincase seal PD26, clutch sprocket seal PD25, clutch carrier seal C18 and make sure there’s plenty of gasket cement on the splines of clutch shaft G3.

Plates, drum and linings: obviously all need to be true and good.

Smooth lift of plate: make sure that there aren’t any notches worn on sleeves C15. Check that the springs C29 aren’t binding in their cups C30.

Even lift of plate: Check the spring forces under load – for example using a set of bathroom scales and a drill press, measure the force needed to press each spring just into its cup. If they aren’t matched, arrange them in order around the clutch, for example, strongest, weakest, strongest but one, weakest but one, strongest but two, weakest but two.

Shoes pivots: If the shoe pivots C5/1 are worn, they can be replaced, and if the holes in the shoes are worn, they can be bushed, but care needs to be taken to maintain alignment and the bush needs to be thin so that the shoe does not break through.

Shoe centralisation: the plungers C11/1, when both at their outer limits, should just hold the shoes symmetrical without any play. If not, you’ll need to tinker until they do.

Plunger travel: The screws C12 should be adjusted to allow travels of 0.235” plus or minus 25 thou for the plunger in shoe C7/1 and 0.295” plus or minus 25 thou for the plunger in shoe C7.

Shoe clearance: You need at least 25 thou clearance between the shoe linings and the drum. If less, remove lining material.    Ken  12/28/06

Clutch photo:
Clutch Parts:

Centralizing plungers: Check to see if your Plunger springs are broken, partially the inner, they often brake with worn plunger holes. They should be counter wound to each other. There was a lot, years back, that weren't. The maximum travel of the Plungers is adjusted with the C12 screw. For the C7 shoe it's .295" and for C7/1 it's .235".Use a damp finger of oil on the C17 bushing. Dave Hartner  1/30/06
Centralizing Plungers:The correct spring determines the tension. How do you know the springs are 'correct'?.  lbf = pound force ,C7 14 to 16 lbf ,
C7/1 18 to 20 lbf. David Jones  1/30/06
Centralizing plungers: I have never  measured the actual pressure at the plunger .  In truth for a hot bike we adjusted the springs while set up to spin the shoe assembly  inside it's drum all mounted on a dummy shaft in a lathe so that actual release speed can be observed as it spins up.   However,  it became clear that a man's firm hand thumb squeeze inwards, and this with the springs still allowing  full plunger travel  for both  shoes, seemed to work well.  When stationary and assembled on the shaft inside the fitted drum, the plunger should butt firmly (without a gap) against it's intended pin. The springs delivering the plunger tip across the gap.  If a gap exists then corrective measures are needed to eliminate it.  Mill out the well further or a longer plunger must be turned up. Only then does the spring  pressure fully withdraw the linings away from the drums face giving freedom from drag and clean shifts.  There should  be a gap of  around 25  thou. between any close  proximity of  lining to drum,  run a feeler gauge around the gap between the shoes and the drum surface to check this.  It is necessary to have this spacing because  of drum wobble allowed by the inner sprocket bushes running  fit /clearance as the drum rotates around the shoe assembly. If the drum rubs against the shoes this will  result also in drag. If all tolerances are kept snug the results will always be clutch drag, only with a  rather  loose " kinda  worn " condition will  the desired   sweet release be acheved.  S.M. Biberman  4/25/05

Clutch Centralizing Preload: The limit of plunger travel should be adjusted using the large screws via a hole drilled in the shoe.  The correct spring determines the tension. Looking at the assembled clutch with both plungers pointing upwards (C7 shoe on left and C&/1 on right) adjust the plunger travel as follows:
Left hand plunger should have 0.295” + or minus 0.025” of travel
Right hand plunger should have 0.235” + or minus 0.025” of travel     Bill   1/20/05
I was discussing
Vincent clutch anomalies with John Macdougal and Dan Smith at a Rally. They explained an interesting mod. C21 and C23 are converted to friction plates by bonding on suitable material. C24 is remade in thicker section. The assembly distorts less when hot because the dished plates are now somewhat insulated and C24 is stiffer.  Steve 10/22/02

Suzuki Clutch: According to the instructions that come with the Outlander kit, you can use anything from a GS650 to a
GS1000 4-cylinder Suzuki clutch.  I am using a clutch from a 4-valve GS750 because it has a metal band around the clutch housing.  I got if for nothing from a local Suzuki shop.  I just had to remove it from a wreck in their bone yard. John Mead  5/8/02
Discussion by Neal Videan about his V3 clutches:   I have read  the discussion about clutches and which of the ones on offer members should buy. The V3 product  I manufacture has several differences to the others on offer so I thought by explaining here it would get to the broad base of owners.

I developed my unit after looking at modern bikes and tried to incorporate as many of their features into mine as possible. I drew the entire unit up on AutoCAD to make sure it would work and fit in properly before a single part was made. What I didn't allow for at that time was variations in clutch cover castings that have be reproduced as spare parts since the original factory spares ran out. Different internal depths on these where the depth was less than that of an original I found my units
fouled by up to 2 mm on the inside of the cover, a minor modification allowed me to reduce the overall width of my unit to allow for some cover variations. But, as on any of the  multiplate products or standard clutches if the outer cover is so thick and shallow on the inside they all can foul.

The major difference with my unit is that it uses 8 bonded friction plates and 7 intermediate steel plates, this gives a much
greater surface friction area, hence, the greater the gripping area the less spring pressure required resulting in a lighter lever action than others with less plates. It is also worth noting that the plates I use are standard Kawasaki readily available either genuine or aftermarket. The clutch pack (8 plates) is what is used in their most modern superbikes putting out over 120

The outer pressure plate is made of pressure injected aluminium with recessed design, this allowed me to be able to get so many plates in. It also has a sealed ball race in it that the pushrod button rotates in. This button is radiused to locate the outer ball end of the pushrod, this accomplishes two things, a) It ensures the pushrod always lifts centrally, b) it eliminates pushrod wear as the button spins in the ball race and not against the button as Vincent ones do wearing the pushrod and adjuster away.

Wet or dry running, - In my bikes I have one wet and one dry, I haven't noticed any difference to their operation. Some customers have asked me is it ok to use chaincase oil in the clutch, I recommend to keep the two compartments separate and use different oils but they will be ok if a 10W/40 is used in both but I do not recommend using AFT in both, only in the clutch compartment. If you use the 10W/40 in both the large chainwheel seal can be removed but 3 or 4 x  6mm holes need to be  drilled through the chaincase at the chaincase oil level in the clutch compartment to allow the oil to self level. In my instructions I say to drill  and tap a hole in the back of the chaincase for the oil level/filler plug if run with separate oil, this hole can be in the rear of outer cover if you don't want to drill another hole in your chaincase.

As I know what it is like to buy a product and then find you need more than what's included I supply the gasket for the outer cover including one for a spare, the C20 mainshaft nut, a pre radiused new pushrod and the 6 High Tensile Socket Head clutch drum screws that I also make.

My ESA adaptor, this increases the effect of the adsorption by 100%, if anyone has ever seen the standard ESA in operation on an engine dyno with a strobe light you can see under high load or quick intermittent loads such as happens changing gears the standard unit becomes fully ramped up on the facecam, when it is in this position it isn't giving any cushioning effect at all. On series D the factory tried to improve on this design inadequacy by increasing from 18 to 22 spring holes, for it to really function adequately however a minimum of 32 of the standard pressure spring sets is required, mine takes 36 sets to ensure it does work adequate. This mod was a proven thing when Alec Corner won our Bathurst races on the Frank Sinclair outfit several years running in the sixties.

The PD9R rubberised tensioner blade I developed for the RTV engine, this is a new standard spring steel blade with a vulcanised Nitrile rubber pad on it. This reduces the clatter of the primary chain hitting up and down against the bare steel blade. I give these free when both a Clutch and ESA are purchased.    Neal Videan   4/10/02

Vincent clutch plunger travel:  About 30 years ago I came across a works drawing for the clutch and noticed that there was some information not mentioned in any other document.  The spring loaded plunger C11 is fitted to both C7 and C7/1 shoes and the drawing I have shows that the adjusting screw C12 should be adjusted for travel and then locked in place. I presume the spring tension is not important and that the travel is.

The two springs inside each plunger are found in other places on the bike. One of the springs is from the engine shock absorber (ESA) - PD27 - and the other, that happens to be counter wound and fits up inside the PD27 spring, is from the oil relief valve in the timing chest OP11. The drawing shows that the adjuster in shoe C7/1 should be adjusted for 0.235" (tolerance + - 0.025") travel, and C7 should be adjusted for 0.295" (tolerance - 0.025") of travel.  The words 'Check only' are given alongside each of these adjustments. The shoes have their numbers cast into their sides.

I had my friendly draughtsman - an ex employee draughtsman of the BSA motorcycle factory - redraw the factory drawing
for me and I in turn took a pile of said drawings to the San Francisco international.  I thought that they would look
nice on the workshop wall.  I only managed to sell two or three and handed the rest to the VOC publishing company
people to sell.

My friend Bill has a very nice Black Prince that had a problem with 'grabbing clutch'. We had tried all the usual remedies so he had a local Black Shadow owner with a machine shop make him an adjuster C42/1 with a built in guide for the pushrod G96. This modified adjuster now keeps the clutch plate C23 square to the rod as it is lifted - no more problems. It is a tube extended down over the push rod - simple as that!   Andrew Rackstraw  1/03/02

Clutch Drag: As the springs are compressed to equal lengths, as dictated by the length of C15, even lifting of the outer plate depends on equal spring  characteristics for each pair situated across from each other.  A while back I had uneven lifting, even with brand new springs whose free lengths matched within a few thousandths.  When tested under fixed  deflection (using a lever and a bathroom scale), though, the actual tension produced varied between springs by up to 10%.  After matching the springs on this criterion, the clutch plate lifted evenly.  Smoother engagement  resulted, and no drag.  Dave Hartner 8/7/01
Just a note to report the results of my attempt to
eliminate the clutch drag experienced on my Shadow with a hot engine.  I made two modifications to fix the problem (a bit unscientific, as it's usually wise to change only one thing at a time), and they appear to have succeeded:

 - I noticed indications of contact between the clutch shoes and the inner clutch plate C21.  Per KTB, I slipped an ET98/1 thrust washer over each pin, beneath the plate, to create clearance.

 - As noted earlier, the clutch springs were not allowing the plate to lift evenly - despite having been measured and matched so that equal length springs were opposite each other (length difference was only in the .010" range anyway).  I rigged up a lever arrangement with a bathroom scale, and found up to a 10% force variance between springs when compressed a fixed
distance.  Armed with these new numbers, I arranged the springs so that equal-force units were opposite each other.  The moral of the story seems to be that even with springs from the same source, length is not a reliable indication of pressure when compressed.

I'm happy to report that these mods have fixed the clutch drag problem, and also created a broader range of engagement making smooth starts easier. One area I didn't address, but which is probably worthwhile, is ensuring that the C11 plungers abut their pins without any clearance.  This idea comes from the excellent treatise Big Sid sent out a while back, which is
available at               Cheers, Dave Hartner  10/20/00

If the clutch plate is dragging on the shoes. Put nine 5/16" washers on the C14s to give some working space down there. The C20 nut shouldn't have much more than ten thousands clearance max.   Have fun, John  6/26/00

Minor correction - to keep you out of trouble on that clutch - 6 washers are in order. One on each of the outside posts of each tripple set. A washer on the middle post will overlap the others  and you won't get a flat support for the inside plate.  Mike Hebb 6/26/00

John`s  Correct about the inner plate touching the top of the shoe pivot pins, usually because the things are so old now the plate has deformed with use , and needs flattening , you will probably find the plate dished and a little pressure under the press , suitably supported will do the job. Then surface the plate flat with a light rubbing on a sheet of abrasive.  The washers will cure the touching but not the deformed plate. As john says there needs to be about 10 thou end float. Do not go less than this as you will not be able to change gear when the engine gets hot. 10 -15 is fine.   Trevor  6/26/00

From: , Date: April 7, 2000.

The Clutch - Part One:   To begin with, one common bitch which has bedeviled Vincent twins since the early Series  B 's has been to suffer from a violently abrupt take-up on initial engagement .   The engagement span seemed to cover one quarter inch or less and that near full extension of my fingers. The all too simple fault is the lack of frictional bite or co-efficient of friction between the surfaces on the outer plate clutches rubbing faces.  Both sides of the inserted segment plate and the inner faces of the two flat steel contact plates  in too many cases needed there to be full and firm marrying together to transmit enough torque to move and set the servo links into the leading edge jam mode between shoe segments and drum face .  By that point ones fingers were all but fully extended and beyond any delicate control  ability. Their load was shot . What was needed to restore that lost control over the frictional modulation too soon spent ?

More and different surface bite / textural characteristics proved the answer and the cure .  The flat steel faces were ground truly flat to each other so ensuring full working area with no cupping or bowing of any area . The inserted plate is best replaced by its racing Ferodo brother if available and it, or the inserted plate,  is surfaced both sides on medium emery sheet laid over flat plate glass.   Next, go back to the steel plates and similarly rub them on the emery in a figure eight  pattern .  Blow clean , ensure all is grease free . Reassemble cleanly with a fresh set of matched springs if available.  Re-adjust  as per Riders Handbook and test ride .  If the remainder of the clutch  mechanism  is  up to snuff then you will be rewarded by having a  sweet broad release span, this now taking up with ones fingers nearer to ones palm, and leaving lots of  modulation travel .   All of this due to a sharper bite and better keying - in  engagement action . Only a light kissing surface lay-on is needed to force those links out - and all the remainder of the lever / plate travel becomes playable like a volume control.  Try it and be amazed!     S.M. Biberman

The Clutch - Part two:   With the outer plate mechanism fully  removed right down to the protruding nine pins  (C 14), observe with a strong  light that both  faces of the centralizing  plungers are indeed butting their respective pins (C11/1 against its C14) .    The springs within those plungers must shove them firmly against the pins, not nearly or close-to , but
against them .  If such is not clearly the case it must be  made to be so .  Fully intact springs will  do this unless the  inner counter-bore in  each shoe casting be too shallow to allow  it  - or the  plunger be too short to protrude far enough .  Which ever be the case -it must be corrected.  Deeper counter-sink or make up longer plungers .   This relationship is what retracts the lining segments off the drum surface (C/1) every time you lift the clutch lever.

To counter the drum wobble always seen, this the result of the necessary operating radial clearance between
those two bronze bushes within the large rear chain-wheel and the shoe carrier shaft,  there needs be no less than 20 to  25 thou . gap  between any shoe segment at the closest proximity of the inner drum rubbing surface .  This to prevent any momentary kissing between shoe segment  and the drum as the drum does its dance around the shoe carrier assembly. There must be clearance always when those plungers do their thing.  Not sometimes - always !

A light cut off the drum face to improve roundness and  surface grip is suggested, and  paired segments need near identical thickness for best grip .  Note that none of this alters in any way the original design concept only seeks to Blue-print and secure normal relationship and inter-action somehow lost over 50 years of swapping pieces about .   Observe that friction / lack of that tiny necessary lash at the big central nut (C -20) interferes with this entire important motion .  A  nice firm full stroke against ones thumb seems to satisfy the plungers needs, neither too hard nor too soft.  More later on high -rev shifting .   S.M. Biberman

"Clutch Thy Beast" by Leslie Goode (Originally appeared in NorCalVOC's "The Vincent Clatter" - newsletter edited by someone called Bill Easter)

Dedicated to the Vincent Engineers who designed this clutch - they were brilliant.  Also for my daughter, Jacqueline, for putting all this together for me.  Thanks to Dave Malloy for helping me to prove my point, and to all the other Vincent owners who encouraged me to write this article - Les

In the early days I have read of and experienced "clutch problems".  Mainly oil seal C18/1 would leak profusely, also oil would pass seal PD25.  Other malfunctions showed up over the years, clutch slip and clutch binding, necessitating pulling in the clutch lever and counting to five before engaging gear, and shifting into neutral before coming to a stop.  All of these problems, some of which are caused by improper parts, can be eliminated by paying careful attention to detail.  Unfortunately, no publication that I have read has mentioned all of these details.  In the late 60's, I replaced C18/1 with a Bosche distributor "O" ring which is actually "D" sectioned.  It has not leaked since.

I had replaced seal PD25 many times before I realized that the scroll on bush PD24 was facing the rotational directional direction, causing oil to be pumped into the bush against a seal that was not doing the job it was supposed to do, i.e. "seal the oil".  Again I replaced seal PD25 stock Vincent part from Conway Motors (London).  I "soldered up" the scroll - no more leaking.

Some years later I purchased a new PD24.  I inspected the scroll and lo and behold I was not the only person to know about the scroll, and probably not the first.  Some engineer had redesigned the scroll to face away from the directional rotation, causing a scavenging effect on the oil.  Since then I have purchased two more PD24's with scavenging effect scrolls.

Last year (1997), during periodic maintenance, I noticed the clutch carrier felt loose.  I duly ordered one new PD24 and one new PD22.  I also ordered a new C3 and springs from of our main parts suppliers.  Great surprise!  The scroll had been replaced with a more generous groove cut into the bush facing the rotational direction.  Since I had purchased a new clutch shoe carrier (C3), I reused a serviceable old PD24 (with reverse scroll) and a new seal.  I installed the new PD22.  I boxed everything up and went for a ride.  At first everything was fine.  The clutch disengaged instantly and was very smooth on the take off.  I had ridden about 210 miles by the time I got home.  While the machine was still hot, I dismantled the clutch.  PD22 was binding.  I reordered a new PD22 and PD24 from another well-known parts supplier.  While waiting for these parts to arrive, I sacrificed my old PD22 to make an "in-situ" extractor, as I did not want to take the primary drive apart again.  I then removed PD22 and on inspection and comparison with old bushes, the new PD22 was not self-lubricating and had fried.  A few days later my new bushes arrived.  They were identical to the previous bushes I had bought - same manufacturer ?

I went to a bearing supply store and purchased a large, flanged self-lubricating bush (several actually) and machined it to the correct size.  I installed it in time to ride to Dave Malloy's meet in Colfax.  No more problems.  I checked my spare plate carrier bushes (C17) and they are not self-lubricating.  They will never be used in my Vincent.

As written in the Instruction Sheets, "There is often a slight oil leakage past the best of seals, particularly when they are new.  In fact, a slight weep is necessary to keep the lip lubricated."  This may have been true at the time it was written, but it is unacceptable today.  Modern seal design and materials are far superior and may well work fine with a "grooved" PD24.  But with my past experience, I am reluctant to try it.  To check if bush is self-lubricating, gently apply heat to bush flange - lubricant should rise to the surface.  Or using a small sharp wood chisel, pry up edge of flange.  A small piece of flange should chip off easily.  Inspect the color of material where it chipped.  It should be brown in color, like dark rust.

In this article, wherever it states "paint", it means using dark gray primer which dries black and is quick drying.  The reason for painting is so that any unwanted contact from moving parts is readily visible.  Yellow gloss latex is recommended for "location identification" of clutch parts which should all line up with one of the pivot nuts.  Multi colors are required for clutch springs and spring cups.  "Lube" means hi-temp moly paste.  EMGS1 is a holding tool as described in "Know Thy Beast", third edition, page 119, line 9.  It is easily made using the inner clutch plate as a pattern.  Please refer to the following publications for additional information on this subject:
* Rider's Handbook
* Vincent Instruction Sheets
* Vincent Motorcycles
* Know Thy Beast
* Spare Parts List

It should be remembered that the clutch plate carrier and the shoes, also the plungers, move every time upon acceleration and deceleration.  Also the clutch springs tend to settle down at different rates.  Therefore periodic maintenance is recommended at 10-20,000 miles, depending upon riding conditions and/or habits.  The dynamo must not be sealed at dynamo housing.  This is where the primary case breathes, that is why an oil thrower (PD28) is there to separate the oil.  Oil will get past the oil thrower only if the oil level is high (half a cup will do it) and/or too much crankcase pressure is present.

Shoe Carrier: Remove clutch. Pay attention while dismantling for any obvious problems, binding or oil leaks.  Should there be any signs of oil leakage, try and determine where, before taking clutch completely apart.  If you are 110% sure that oil bushes PD24 and PD22 and seal PD25 are in "A1" condition, you can skip taking the primary drive apart.  but if you are only 99% sure, then dismantle it.  This is where a good operating clutch begins.

Remove primary cover and primary drive.  Clean all parts.  Paint primary housing, inside clutch cover, clutch housing, and inside clutch cover.  Inspect carefully the clutch shoe carrier bearing surface.  Check bushes for galling and excess wear, especially PD22, which tends to wear quicker than PD24.  This is probably because the weight of the whole clutch is offset from the bearing surface.  Excess wear of these bushes allows sprocket PD20 to move upwards and forward on acceleration, bringing dynamo sprocket into deeper mesh - hence "the mysterious whine".

If oil has leaked through PD22, then PD24, must be removed to replace seal PD25.  If removed, ensure PD24 was not damaged in extraction.  Try the fit on shoe carrier before reinstalling with Loctite.  If replacing PD22, ensure it is self-lubricating.  Assemble PD20 and clutch shoe carrier and tighten nut to 70# using tool EMGS1.  The PD20 should rotate freely and some end float must be present.  You should be able to wobble PD20 slightly if the minimum required 0.001" clearance is present at the bushes.  If all is well, remove PD20.  Reinstall primary drive and cover after replacing seal PD26.  Paint non-contacting areas of clutch drum and clutch shoe carrier.  Install and fasten nut to 70#.

With gear engaged, rotate rear wheel while observing the movement of clutch drum (wobble).  This can be seen more easily be attaching a small pointer to the clutch cover mounting hole by the kick start shaft plug.  Make a note of how much movement exists.  There are six splines so carrier can be tried in each position.  Finally locate carrier to give the least movement.  Once you are satisfied the drum moves as little as possible, mark one pivot nut with yellow paint and also the mating splines closest to the painted nut.  This procedure compensates for machining tolerances of shoe carrier and shaft (G3).

Shoes: Check pivot holes for wear.  If badly worn, they can be machined and bushed.  Wear on outside of plunger housing is covered later.  If plunger housing bore is worn, it can be reamed out to accept a thin walled brass tubing insert, available at hobby stores, cut to correct length and installed with Loctite.  The brass may wear more quickly than aluminum, but as the tube wall is only about 0.015", it can be easily collapsed with a small screwdriver and replaced.  Renew plunger springs at this time and install without lube.  Also carefully inspect shoes for cracks, especially in the area where center rib joins the toggle boss.  Some replacement shoes have been made with a little less material in this critical area, and they have cracked.  I think the chamfer on the lining at this area should not exceed 3/8" and the whole power of the engine may be applied to a weakly supported area, which could cause the shoe to crack.  The bore for the toggle link pin should be counter-bored (drilled) to allow pin to be recessed slightly from the shoe surface.  Re-drill split-pin hole 90 degrees from original, and trim off excess pin.  Obviously, if linings are worn or oil soaked, they should be replaced.  Molded linings are again available.  A little oil will cause linings to stick (bind) to drum.  A lot of oil will cause slippage.

Clutch Plate Carrier:  Check nut (C20) and bush (C17) for binding or wear.  Replace if required.  Again, beware of bush that is not self-lubricating.  If shoes show wear on outside of plunger housing do not remove any metal from the shoes.  There is precious little there to start with.  Using a small die grinder, carefully remove metal from inside the plate carrier flange between the pin clusters tapering towards the pins on each side.  Trim halfway through the thickness, beveling halfway through through the width of the flange.  Repeat process on all three areas to retain balance.  It is preferred to remove pins prior to grinding.  Polish off any grinding scratches and paint.  I use s/s paint on this item.

Install shoes to plate carrier.  Split pins are not required at this time.  Install onto clutch shoe carrier.  Install nut (C20) but do not fully tighten.  With shoes in a relaxed position, check clearance of bush (C17) to nut (C20).  A clearance exceeding 0.010" will waste valuable clutch pushrod movement.  Adjust thickness of thrust washer (C19) as required.  Also, with the shoes in a relaxed position, there must be zero clearance between plungers and pins.  If clearance exists, the shoes will chatter at idle speed and may even drag on the drum if the linings are still thick.

Replacement plungers may help, or, measure and record clearance between plunger and pin.  Remove shoes.  With calipers, measure length of protruding plunger from a "marked position" on plunger housing, i.e. 0.040" between plunger and pin and 0.336" plunger protruding.  Remove spring and plunger and using a 3/8" pilot pointed drill bit in a hand-held chuck, remove 0.040" from plunger seat in shoe.  With plunger placed back in shoe, the protruding plunger should measure 0.376" (0.040+0.336").  Recheck clearance and adjust as required.  A few thousandths pre-load may be a good idea.  Clean shoes and paint non-contacting areas.  Lube and install plungers and springs, keeping lube off threads.  Tighten spring thimble until it just bottoms out, then back off two complete turns.

Assemble shoes back to clutch carrier, again no split pins.  Do not fully tighten nut.  With gear engaged and rear wheel locked, use EMGS1 to move plate carrier counter-clockwise to bring shoes into contact with drum.  The plunger adjustment will be correct if it can be depressed as additional 3mm, which allows for lining wear.  Turn plate carrier clockwise to check other plunger. Adjust spring thimbles as required to obtain this measurement.  Then back out spring thimbles exactly 1/4 turn.  Apply one drop of Loctite to threads and refasten exactly 1/4 turn.

Install shoes back to plate carrier.  This time lube toggle links, install link pins and two split pins.  Lube the pivot nuts and install plate carrier to clutch carrier.  Install two pivot nut circlips.  Ensure mating splines match.  Install new C18/1 or whatever seal your machine uses.  Install nut (C20) and thrust washer.  Fully tighten nut to 70#.  Put a dab of yellow paint on shoe next to painted pivot nut.

Primary Clutch:  Paint non-contacting areas of inner and outer clutch plates.  Install inner plate.  Paint yellow mark on plate closest to painted pivot nut.  Ensure all nine pin sleeves are exactly the same length.  Polish off any burrs ar scratches from sleeves and install over pins.  Install C27 and nine screws and fasten.  With gear engaged, rotate rear wheel and observe "run out" of plate - it should be zero.  Mark low area of plate (towards gearbox), add a 0.001" shim cut to fit over three pins closest to the low area.  Place shim between plate carrier and inner plate.  Reassemble and check again.  You may have to add or subtract a little to get the plate to run true. (my clutch has 0.0015").  Mark position of shim on plate carrier.  Install lock spring (C45).  Shim compensates for machining tolerances of plate carrier/carrier bush/nut.

Install clutch disc, outer clutch plate, and spring cups with six new springs.  Do not use C27, instead use nine 5mm x 16mm washers with screws and fully fasten.  Pull in clutch lever and insert a tapered drift in lever.  Rotate rear wheel.  The outer clutch plate may wobble.  If so, locate low area (toward gearbox) and slacken one or maybe two screws until plate runs true.  Adjust tapered drift in clutch lever to give about 0.010" clearance at clutch plate.  The screw(s) you loosened are the heavy spring(s).

Sometimes a heavy spring can be lightened by compressing it in a vice until it becomes coil bound.  A spare set of springs could save a bunch of time.  If necessary, line up all your old springs on the bench and try some of the longest ones.  This part of clutch adjustment may be long and tedious.  It is , however, most important that the outer clutch plate is as square as possible at point of contact with clutch disc if a really smooth take off is to be obtained.  The springs can be considered correct when you lift the clutch disc underneath and it drops with a clink.

Mark springs and spring cups and their position on outer clutch plate with paint, either six different colors or three colors 1 dot (x3) 2 dots (x3), also a yellow paint mark to line up with painted pivot nut.  Install C27 with screws.  Install clutch cover.  Reset clutch cable and operating lever in the normal manor while paying attention to detail....That's another article.

Note: A self-lubricating C17 can be shortened to become a PD22, but check flange dimension.  The oversized bush I machined is available from bearing supply stores, part #EF 2024-16 Bunting, $2.16 each.

Return to 

  ont color="#ffff99">Sometimes a heavy spring can be lightened by compressing it in a vice until it becomes coil bound.  A spare set of springs could save a bunch of time.  If necessary, line up all your old springs on the bench and try some of the longest ones.  This part of clutch adjustment may be long and tedious.  It is , however, most important that the outer clutch plate is as square as possible at point of contact with clutch disc if a really smooth take off is to be obtained.  The springs can be considered correct when you lift the clutch disc underneath and it drops with a clink.

Mark springs and spring cups and their position on outer clutch plate with paint, either six different colors or three colors 1 dot (x3) 2 dots (x3), also a yellow paint mark to line up with painted pivot nut.  Install C27 with screws.  Install clutch cover.  Reset clutch cable and operating lever in the normal manor while paying attention to detail....That's another article.

Note: A self-lubricating C17 can be shortened to become a PD22, but check flange dimension.  The oversized bush I machined is available from bearing supply stores, part #EF 2024-16 Bunting, $2.16 each.

Return to