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Vincent Transmission - One, Two, Three, Four
 

Adjusting the Gearchange: There are two things to fiddle with to make a proper adjustment of a twin transmission, whether it be an original 4 speed, or an after market 5 speed.  The two being the G57 and the G61.  When the transmission is in neutral, and the shift lever is in a relaxed position, and the G70 spring is supporting the weight of the G66AS shifter arm, and the exterior foot shifter arm, the picture should be identical, i.e., the distance between the outer male shifter pawl and the inner female shifter pawl, both for the engaging side for low and the engaging side for second.  One other 'must do' thing is to insure G61 is pivoting on the shoulder of G40.  It's easy for G40 to slip away from it's shoulder on it's support bearing.

When engaging the male female shifter pawls, the engagement of the pressure flats of the pawl should be simultaneous with the contact of the relief's of G59AS and G43.  The adjustment of G61 pretty well takes care of the pressure flat adjustment, and G57 pretty much takes care of the relief of G59AS coming in contact with G43 prematurely.  I've found that when you play with one adjustment, more than likely you'll have to play with the other adjustment.  When it's right, you should be able to take the foot shift lever and visually observe the point, or apex, of G59AS, engage G43 in it's cleavage point, simultaneously with pressure contact point, and relief contact point.  The most common mistake in adjusting the shifter, is that the relief contact point is premature.  It's fairly easy to adjust a transmission to shift well, assuming that when in neutral the G40 has very little backlash movement.  If there is excessive backlash, proper shifting cannot be obtained.

A well shifting transmission has a lot to do with mass.  Each shift requires a mass from a dead stop to accelerate over a distance, and come to an abrupt stop.  The mass in a standard Vincent transmission, which is a four speed, that has to be started and stopped, is approximately 20% more than the after market five speed.  To get five speeds in a four speed gear box, obviously the gears will be thinner, thereby lighter.  There are two shifter forks in the four speed, and three shifter forks in the five speed.  The shifter forks are much lighter in the five speed than in the four speed, and much stronger, as they are made from steel.  There is less movement in the gear to make it shift in the five speed than in the four speed.  The large engaging dogs of the five speed, not only allow a better hold in angle cam grind (preventing jumping out of gear), it also is much better in design, which enables the mesh of the gear dogs to actually relieve the cam of the shifter fork from it's duties, and the force of the meshing dogs at this point actually turns the cam plate, not the shifter mechanism.  The five speed is a much better design than the four speed in this respect, as it allows slight roll off throttle shifts without clutch disengagement.

The four speed transmission, when raced, tries desperately to reduce shifting mass by lightening the G32/2 cam plate, and the G66AS shifter arm.   It's a good idea to lighten the G66AS when installing a five speed.  Max Lambky  4/5/10

Adjusting the Gearchange: The alloy block (G49) swings in an arc.  If you loosen the two bolts (327) and turn the eccentric hollow bolt (G57), you will find you are able to turn to high point and low point, the starting position would be the Middle of this travel, then tighten bolts. Once you have placed gear indicator shaft in Second gear,  you turn slightly the shaft to have equal gap either side of that segment by altering the position of the small plate (G61), some have " Ears " some not, this was a modification or to suit those gear changes which were hard to adjust.  The ears restrict travel to not over or under shoot the gear engagement... at times one may need to bend the ears slightly.  You must make allowances for any Play or Backlash .. or find another gear shaft with good segment, etc.   Once you have done this and satisfied, you select the best position in gearbox by turning rear wheel slightly, so you can Swipe through All the gears with gear  indicator lever from bottom to top.  It may take a bit of fine play to achieve.  Place in Second gear after with indicator.  The reason for this is so you can with Gear Change Lever select up or down in One clean movement.   The full travel of lever must hit the Stop in alloy block Both directions.  If it doesn't and the gear falls in or fails to engage,  then you alter slightly the position of alloy block to suit.  This takes longer to explain than do.  Mike White  5/1/09
Quaife 5 spd Gearbox:  http://www.quaife.co.uk/shop_image.cfm/image/681/product/Vincent%205-speed%20Quaife%20gearkit

Glad you could read the Issue 3 G/A drawing dated 27.03.03.  More info below:
If it's of any interest, here are the ratios of the Quaife / Surtees 5-speed Vincent box:

1st    1:2.46
2nd    1:1.61
3rd    1:1.34
4th    1:1.075
5th    1:1

...and the drive sequences (numbers refer to the two end digits of the Quaife part numbers on the G/A drawing):
1st    Selector 20 Leftward    28 -> 29 -> 13 -> 09 -> 18 -> 07
2nd    Selector 20 rightward    28 -> 06 -> 14 -> 13 -> 09 -> 18 -> 07
3rd    Selector 21 rightward    28 -> 06 -> 16 -> 18 -> 07
4th    Selector 22 leftward    28 -> 06 -> 03 -> 13 -> 09 -> 18 -> 07
5th    Selector 22 rightward    28 -> 06 -> 07

... and the small items' descriptions:
Item 2 (2 of): thrust washer (however, this part shown next to layshaft gear A-1E1-18 absent on my box, as that gear is a driven interference fit to layshaft spline tapers).
Item 172: needle roller bearing
Item 292: C-clip
Item 586: needle roller bearing
Item: 675: seal
A-1E1-04: thrust washer
A-1E1-05: plain bush
A-1E1-08: thrust washer
A-1E1-11: plain bush
A-1E1-12 (2 of): thrust washer
A-1E1-15: plain bush
A-1E1-17: plain bush

I guess A-1E1-18 wasn't manufactured as one with the layshaft as they couldn't have machined the dogs that way.   Box main parts shown at http://www.quaife.co.uk/shop_image.cfm/image/681/product/Vincent%205-speed%20Quaife%20gearkit

Phil Blakeny  6/9/08

Comet Trans:  Correct one is BAP.   The B52/CP/GB boxes are all the wrong sizes cases; shorter shafts and different gears/selectors from the pre and post-war Comets.  One can make expensive mistakes buying these boxes in the belief they are BAP ones.  Don't ask me how I know... Peter Barker  4/15/08

Burman Drawings:   http://vincenthrd.se/skisser.php

Various Grease/Oils for Burman Trans.:
*  Castrol Spheerol L-EPO Semi-fluid self-levelling grease suitable for centralised lubrication systems and grease filled gearboxes.
*  Penrite Semi-Fluid grease for Burman boxes.  It is best to do it on a warm day (or lace the container in a bowl of hot water) otherwise it takes an eternity to fill.    Do not try to run the bike for a few hours after filling as it takes a while for the grease to find its own level. Some people add about 50 ml of light oil too.
*  Millers of Brighouse sell a grease Delta  EP000 in 3 Kg  drums for a tenner.  See their website for depots.  Very liquid. 
Burman Gearbox Oil: It  can be a cause of  rapid bushing, etc. wear if the grease is too thick  and does not  flow readily.    The gears will tend to cut a track through it  after which it does not flow into them continously.   Also it will not enter tight bushing clearances.   I suggest a small quantity of  soft grease followed by   sufficient  90 wt. gear oil  to acheve the correct level.   This way the soft grease gets carried into any  leakage paths sealing them while the job of  real lubrication  is  delt  with by the gear oil .  This works  nicely  in our Meteor  and  if not overfilled  it  rarely shows any seepage.   Sid  6/18/07

 I have a Comet with a Commando gearbox. I fitted a main shaft seal from the Spares Company so that I could use automatic transmission fluid in the primary drive. I mounted the gearbox sufficiently to the left so that there was room behind the clutch for a plate carrying an oil seal. I was able to do this as I had mounted the gearbox in a fixed location and fitted a twin chain tensioner blade, suitably narrowed in  the primary chaincase. All the springs were removed from the Vincent ESA and the two halves welded together, the shock absorbtion being handled by the rubber inserts within the standard Norton clutch. This results in a rigid assembly and a very sweet transmission. There is absolutely no justification for fitting a triplex chain to a Comet, there's isn't enough torque there to require it.   Roy Cross
It is possible to get the gearbox out of the Comet without dismantling the whole machine though obviously the clutch will have to be removed. It all  depends on the two chain adjuster bolts that allow the gearbox to swivel backwards and forwards for primary chain adjustment. Ideally all you need to do is to unscrew these two bolts and remove the gearbox mounting bolts and with a lot of cursing and 'ackling' (wriggleing about) it will come out. Warning ! Unfortunately it is usually impossible to remove the chain adjuster bolts as in service the working ends that bear on the lower gearbox mounting bolt bell out. Any attempt to remove them will strip the threads in the gearbox casing. However I have managed to remove and replace several Comet gearboxes over the years with bolts that were belled out. It is a tedious process requiring much patience. What is needed is to keep adjusting the positions of the adjuster bolts relative to each other and by trial and error, so far, I have always found a position where I can wiggle the gearbox out. Tightening of the Gearbox is usually the drive side layshaft bearing. Heavy
grease never gets to it hence the advice to put in the odd spoonfull of  engine oil.  Hugo  3/10/07
Pre-war, the Burman BA- BAP traansmission was made with three sets of gears:
* HS, which is the set we know on the post-war Comets.

* LS, which appears to be Trials: only the constant mesh (4th.) gears differ from the HS.

* TT gears as fitted to competition models.

Post war, only the HS ratios seem to have been manufactured, and as we know, the Flash used the Albion box, for which a wide selection of gears were available.  I do not consider either the HS or TT gears were really the correct ratios for their respective uses. It would, of course, be possible to redesign each set, which would probably mean replacing virtually every gear in the box.  However, for road use, there is an interesting compromise based uniquely on pinions which once existed: to use the standard 1st. and 2nd. pairs which presumably exist in your present box, in reasonable condition, with the TT 4th. and 3rd. pairs of gear- that is, changing 4 pinions.  This would give ratios of 1:1, 1.16, 1.45 and 2.3, or 100, 86, 68 and 43%.
Bruce McNair  2/9/02

Pre-war Burman Transmission spares list:
  http://www.btinternet.com/~paul.wirdnam/sq4/1930/burman_frameset.htm
Synthetic oil is banned from being used with our kind of bearings, simply because the coefficient of friction is too low for the rollers and balls to rotate, causing them to skid, and wear with flats on them. Any one out there have any Long term usage with Synthetic, e.g. Mobil 1 ? And had a look at the results.
Trevor
A quick check for gear changing problems is to change gears with one hand - with the bike on the rear stand - whilst restraining the indicator lever G81's travel by holding the indicator with the other hand.  When the gear lever has reached the end of its travel carefully check to see if there is anymore movement of the indicator lever to fully engage the gear being selected by moving the indicator lever in the same direction it was travelling. If there is any more movement of the indicator lever required then the camplate G32 is not travelling far enough by gear lever operation.

If this symptom can not be cured by adjusting the selector mechanism then the cast alloy block G49 needs opening out with a file to allow more travel. Check that this is infact the problem by carefully adjusting G57 stoplate adjuster so that more movement of G81 is required to engage both 3rd and 4th gear.

This will prove the need for the block to be opened out - a fairly simple job with a file and G49 in a bench vice 'a little at a time' till you have the right amount of travel - being careful to remove the metal off the place on G49 that stops the travel of the gear lever or maybe a little off both stops with G57 in the centre of its travel ( to make allowance for future adjustment). G49 has a concave shape where the metal has to be removed - there is no need for this shape, a flat surface is all that is required to limit the travel of the gear lever.

I have had to carry out this job on at least 3 separate bikes after which the gear change has been transformed - having giving the gear lever just that little extra travel.

I have also discovered the importance of adjusting the battery carrier nuts E80 to compensate the load on the pivot bearing plate G50 when the foot rest hanger bolt is nice and tight for a really nice gear change.  If there is any stiffness in the gear change when the engine is hot - try slackening off the hanger bolt just to see if this is the adjustment needed.  If so, adjust the 2 E80 nuts outwards and pinch up the foot rest hanger bolt again and carry on riding.   Andrew Rackstraw   8/14/00


When you get a situation where the box jumps out of top gear as your try to grab a handful , the usual reason is that the detent did not go into its position on the camplate, this is the positive position.  On some later machines you can find that the detent Cannot even get that far. The G39 being stopped from rotating into position by the bevel stop pin. This can only be checked on assy. with the gearbox assembled and with the detent out, look into hole to see where the camplate is.  If you have had a problem with top gear jumping, this is the cause.  Trevor  8/14/00

Denny Delzer asks why his gearbox jumps out of second gear ? This means that the detent is not sitting in the camplate perfectly, this could be for two reasons.
1 On changing gear the gear pedal is depressed too lightly , allowing the gear to change but the detent does not sit in position.
2 The set up of the gearbox does not allow the detent to sit in position.

Even if you have as you say NOS parts or good condition parts in the box, this is not a reason to say there is nothing wrong.
So what you have to do to check out the set up, is to remove the detent and visually check if the camplate is in position, when the box is in second gear.  If it appears to be, replace the detent spring, and test ride.  If the problem still occurs you have a problem with the set up. The only way to check then,  is to use my checking fixture and sort out the problem.  I won`t begin to tell you what could be wrong. I`ve lost count.   Trevor  6/16/00

 Improvements to shift quality
       Many - even most of the Vincent motors we have dealt with in our work lack one small but extremely valuable Works up-grade dating back to the very early years.  A simple looking alteration first suggested by one of the fine road-testers active then, one Bob Brown.  Very keen and dissatisfied with the tendency to over-shift  present in too many units that he rode -Bob came up with the notion of adding restraining tabs or ears to both sides of the pawl carrier centralizer plate G 61. This became G 61 /1 with the addition of two projecting motion stops brazed one to each fore and aft edge.  So utterly simple it seems, yet properly positioned truly worth more than its weight in Gold.  Perhaps because it is not so drawn in our  B/C  Parts Books yet carries the corrected  part  number.  Few have picked up on it and the magic it performs.  My first exposure and explanation came to me way back in 1953 while shoping at the Works Spares counter where the modified piece was handed  me and called the Bob Brown Special.  Friendly chap behind the counter there confided that I'd surely want one of these as he dropped it into me waiting hand.

There is a subtle touch to getting it swung  just so in order to derive the best  results out of those metal stops that Ill try to convey to you my friends.  The aim is to snub off excess inertia / momentum imparted  to the spinning cam plate during a too spirited shift . This energy  tends to rotate the plate past its next notched position -- forcing excess rotation to drive the plate - lifting the indexing plunger up out of that desired notch and so allowing further rotation towards - or into the following ratio selection.  Over selection results . My experiance when fettling these pieces is to allow the ratchet to closely approach  - not enter fully - the up coming notch. Notice my word choice carefully . Closely approach only and Not fully enter the cam plate notch.  Thus the tab contacts and acts to slow/snub off  the excess speed,  to where the spring driven detent plunger can take over control and deliver sweetly  to the bottom of the notch, that unwanted  momentum already absorbed in the slight flexing of the arresting stop. Only the spring pressure remains to fully seat the plunger into it's homing notch. Barely any of  the shift lever thrust and rotational energy exists in the plate as it enters the edge of the notch slope.  Duplicated in both directions and  I've seen very  little  need to bend the stops much, and the shift becomes dead reliable and pleasing beyond words. Much of the ease and sweetness is dependant on full clutch release, and  I shall delve into that clouded subject  in my next effort , however let me say  that  after all these decades  I am still and ready to prove that the original Vincent  clutch can deliver better feel  and  function than a  multiplate conversion  for greater mileage and less parts wear than any  in my experiance.   S.M. Biberman    21 Mar 2000

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