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Vincent Transmission - One, Two, Three, Four

    Transmission Restoration, V Twin

All B, C, and D twin transmissions were basically the same.  However, from 1946 to 1955, minor weak points in the original concept were discovered. The right hand crankcase casting was modified in the transmission area, in that additional meat was added for greater support of the shifter cam spindle and the shifter shaft support area.  The cam plate shifter quadrant received a support band around the shifter shaft coupler tongs.  The shifter pawl adjusting plate received over shift stop gears.  The Lightnings, if ordered, had a higher low gear ratio than the standard pedestrian twins, G9/1 had 21 teeth, G11/3 had 27 teeth, that would be the double gear.  The Shadow and Lightning shifter cam plate can be identified by a series of quarter inch lightening holes.  The transmission counter shaft sprockets can be identified in the following manner.  A road model sprocket is solid, except some Shadows, not all, were drilled for lightening, and had 21 teeth, giving an overall delivered gear ratio of 3.50 to 1.  Lightnings were thinner, to accept the 520 chain drilled for lightening, and had 22 teeth.  Most Lightnings left the factory with an overall gear ratio of 3.27 to 1.  During the Korean war, some metals weren't available.  Transmission gears suffered during this era, with low grade gears.  These gears can be identified by their number, 352.  Vincent transmission gears that are identified by designation number such as EN36 are of better quality, much stronger.  

If the motorcycle is in running order, it's a good idea to take it around the block a couple of times prior to tear down and restoration, to determine the preliminary condition of the transmission.  Finding out how it shifts, and finding any obvious defects, like jumping out of gear, or excessive noise emanating from the transmission area, could be helpful later on. 

Start your tear down by swinging the rear brake pedal assembly out of the way of the primary.  Place the bike on the rear stand.  Swing the front stands into position to achieve a four point support for the machine.  Remove the clutch derby.  Place a drain pan under the transmission area.  Remove the drain plug from the primary chain cavity.  Now go to the right side and remove the transmission drain plug, found forward of the transmission shift cover in the right hand crankcase side.  The drain pan should have a capacity of four quarts.  Now remove the clutch assembly.  Inspect the area directly below the now visible primary cover seal. If dry and free from excessive oil, the replacement of the seal probably won't be necessary.  When there's no drip from the primary drain plug, you can remove the primary chain cover.  Inspect the primary seal again.  It should be soft and flexible to the touch, with no hardness and no visible cracks to the rubber seal portion.  If the seal appears suspect in any way, replace it. 

You can now remove the primary chain clutch sprocket and the crankshaft sprocket.  Inspect the retaining bolts of the transmission door.  They should be drilled and safety wired.  Often they're not.  The reason for the safety wire necessity is the fact that the door receives a twisting torque caused by the lay shaft gear cluster trying to climb the main shaft cluster during acceleration and deceleration.  The visible hex head cam plate indent plunger and spring assembly must be safety wired as well.  The twisting torque has a tendency to loosen the retaining bolts, and loosen the aligning dowel in the bottom circumference of the transmission door.  Next inspect the transmission's main shaft end clearance.  This is easily done by taking the exposed main shaft and moving it athortship back and forth.  The end clearance shouldn't exceed .007.  If .007 is exceeded, write down in your tear down reference notes, the amount of shimming required to achieve a .005 to .007 end float.   

You can now go to the right side and remove the exhaust pipes.  Remove the adjusting screw on the transmission shifter cover.  Remove the clutch cable access cover.  Unhook the clutch cable from the clutch release arm.  Remove the clutch cable from it's clutch cable housing stop bore.  Place cable out of the way.  Shift transmission into neutral.  Remove shift lever, kick start lever, and transmission gear indicator arm.

As the transmission shifter cam plate spindle is under the battery tray, it's necessary to remove items in order to gain access.  Remove battery, battery strap, and the battery tray support bolt.  You can now swing the battery tray up and out of the way.  Swing the right hand foot peg assembly up and out of the way. 

Place a pair of vise grips on the shaft of the gear selector positioning pointer.  Feel for any slack or backlash between the shifter cam plate bevel gear and the bevel tooth quadrant.  You're testing for excessive gear wear, and improper fitting of parts.  The proper mesh of the bevel gear and cam gear is important for a nicely shifting transmission.  Often the shaft alignment through the transmission cover is out of align, causing friction between the shaft and the outer cover, which every time causes an ill shifting transmission.  This is especially true when using a cover from another engine, or a reproduction cover.   

You can now remove outer transmission shifter cover.  Remove kicker quadrant, inner shifter arm, and shifter pawl assembly.  Leave the adjustable stop tab in place.  Before removal of the adjustable pivot for the inner shifter arm, scribe it's adjusted position around the two washers. The pot metal slotted pivot pin support scribes easily.  When the transmission is reassembled, this gives you a good starting point for shifter adjustment.  Now you can remove the pot metal slotted support pivot pin piece.  Next remove the circlip from the transmission main shaft, and remove the kicker ratchet assembly.  Remove the clutch rod assembly.  The very first clutch rods were of one piece.  The one piece assembly caused excessive wear to the throw out arm.  The multi piece throw out rods reduced wear drastically, but didn't eliminate it totally. 

After accomplishing all of the above, you will have total access to remove the transmission shifter mechanism dust shield.  This pops out easily with a screwdriver in the slot provided.  The felt seal is now exposed and can be removed.  More than likely it'll be reusable. 

Next remove the counter shaft sprocket nut.  You'll find the nut is staked, probably in more than one place near the trailing edge of the nut thread in relation to the transmission sprocket spline.  Probably the nut will have chisel marks from previous removal, due to the fact that most home tool boxes don't contain a large enough socket.  When this is encountered, renew the nut.  Getting rid of the ugly always makes you feel better.  After the nut and the female dust cup are removed, you can check the counter shaft sprocket's splines.  If the spline mating surfaces are too loose, it will cause a hammering action, which in time will eliminate the sprocket spline altogether.  Not a good thing.      Max Lambky  11/5/10

Transmission Restoration V Twin (2)

Remove the safety wire bolts, securing the transmission bore to the left hand engine crankcase.  Remove the shifter cam plate indent plunger assembly from the transmission door.  With a heavy duty stubbie screwdriver, remove the shifter cam plate spindle screw.  It's located at the top of the transmission in the right hand engine case, near the mating surfaces of the two cases.  The spindle is usually staked.  More often than not the spindle is easily removed without much trouble, but sometimes you need a scribe to catch the threads for removal. 

You are now ready to remove the transmission gears and shafts from the transmission cavity.  With a rawhide or rubber mallet, from the right hand side of the motorcycle, hit the mainshaft on the end, driving the transmission door from it's mating support bore in the engine's left hand case.  Remove from the left hand side, the transmission door and mainshaft.  Most of the time the layshaft will come out from the door, along with some gears.  The rest of the transmission parts will find their way into the bottom of the transmission cavity.  Don't worry about this.  Even with no manual of any kind, the transmission will only go together one way.  The only parts that now remain together are the layshaft bearings in the transmission door, the right hand engine case, and the two bearings of the mainshaft, one in the transmission door, the other in the right hand engine case.  These bearings rarely need replacement.  The two layshaft bearings usually require heat from a torch to remove.  The layshaft transmission door bearing is the easiest, due to the mass of the door.  The layshaft bearing in the right hand engine case rests in a blind bore.  This is the hardest bearing to remove.  The best tool to remove the bearing is a valve seat removing tool.  It will fit quite nicely within the radius of the inner race nearest the engine case, when the lip is expanded.  You can then use the knocker, and with minor heat on the case, the bearing can easily be removed.  The mainshaft bearings can be removed with a half inch drift, tapping in a circular motion around the inner race.  On the right hand case bearing, sometimes it's a good idea to, with a dremmel tool and a small rotary file, relieve the stake overlap.  The transmission door main shaft bearing is the thrust bearing of the transmission.  The bearing is captured with a lock ring nut on one side and the door housing bore shoulder on the other.  This bearing is the aligning bearing of the whole transmission assembly to the engine cases.  The lock ring nut must be made tight to insure proper positioning of the thrust bearing.  The lock ring nut is keyed into position with a split pin, or for the US guys, a cotter pin.  Drill the split pin hole accordingly to achieve this.

Install the shifter cam spindle, insuring that the spindle reaches it's shouldered stop.  Place the shifter cam in the palm of your left hand.  Note the indents on the outer edge of the cam plate.  There are five indents, four of which are for positioning each gear of the four speed transmission.  The fifth indent is for neutral.  If not marked with an end. It's the second indent, turning the cam plate in the direction of rotation.  Place the neutral indent towards your body.  Slide the cam plate into the transmission cavity, and marry the spindle pin to the female bore of the cam plate.  Push upward.  The bevel teeth of the cam plate should mesh with the bevel tooth shifter quadrant with zero backlash, before the top of the bevel gear on the cam plate hits the shoulder of the transmission cam spindle.  If you can't achieve zero backlash by doing this, you must place a small shim under the spindle before screwing it home, or with a grinder, move the shoulder of the pin closer to the threaded end.  Remove the cam plate and inspect the beveled gear.  If excessive wear is noted, the gear should be replaced. 

Next, inspect the shifter forks.  One fork is female and one fork is male.  First check for the straightness of the fork.  This can easily be done on the table of a mill.  Place the fork flat with the cam pin between the T nut slots.  Check for a 90o angle of the male shifting fork with a machinists' square.  Turn a biscuit in the lathe from wood, metal, plastic, or anything that just fits in the female portion of the female shifter fork.  With a second biscuit, 1/2" thick and a smaller diameter, you can now check the female shifting fork the same way. 

Check the shifting fork pins for wear.  Often you'll find worn flats 180o from each other on the pin.  If you find this to be the case, the pins will have to be replaced.  Sometimes you're able to remove the pin with a drift punch, turn the pin around, and insert, using locktight.  Insure that you don't push the pin in too far.  Strive to maintain it's original proud position. 

There are two reasons a restorer or mechanic gives attention to the transmission.  The restorer often is only giving the transmission a thorough look-see, trying to ascertain whether all of the parts are serviceable, and will operate in an 'as new' condition.  The mechanic is usually fixing a malfunction of some sort.  More than likely the problem will be a broken gear, or a transmission that won't stay in gear, or a transmission that doesn't shift properly.  Transmission gears should be inspected for missing teeth and meshing teeth. 

The Vincent transmission has what is referred to as a 'straight cut gear'.  If the shafts of a straight cut gear mesh are straight, there should be no thrust of the gears, assuming that the meshing teeth are in good condition.  When the meshing engaging teeth of a Vincent transmission become worn and lose the tooth's cam chamfer, which holds the gear in mesh, the transmission gear pops out.  The thrust created by the worn tooth becomes greater than the force of the shifter cam spring loaded indent plunger.      

If the transmission tear down was for a restoration, inspect all of the gears and the four bushings for excessive wear and condition.  If the transmission was torn down for repair, a more thorough inspection of all transmission parts will be necessary.  If for instance, the transmission was popping out of second gear, more than likely the meshing teeth are beyond repair and the two meshing gears will have to be replaced.  When the transmission is restored or repaired, always replace the right hand engine case seal.  This particular seal receives the most abuse, and wears more quickly than any other.

One other most IMPORTANT tidbit--when performing a crankshaft out restoration, where the engine cases are split, insure that the transmission bevel gear shifter quadrant is installed along with it's stop positioning spring. 

It may be more convenient, and provide more access, to remove the rear carburetor assembly and place out of the way.  The early B's, had the larger diameter generator, which may need to be removed for access to the cam plate shifter spindle.   Max Lambky  11/5/10

Transmission Restoration V Twin (3)

If you've gone through the previous steps religiously, and all parts have been thoroughly cleaned, inspected, and repaired as necessary, you are ready to reassemble the transmission and replace it in it's home. 

On the workbench, assemble all of the transmission shafts, gears, spacers, shifter forks, and shifter cam plate.  The transmission will only go together one way.  Place the transmission door in a vise, clamping at the bottom where the aligning dowel pin hole is.  Allow enough clearance so that the transmission gear assembly can be inserted into the transmission door.  When the transmission is assembled in it's cluster, you can easily wrap your hands around the cluster and insert it into the transmission door.  When the mainshaft and the layshaft are lined up and started in their bearings, you can take a rubber mallet and gently tap home.  Turn the shifter cam plate, engaging low gear.  Insert the indent plunger assembly into the transmission door, and turn hex approximately two turns, engaging two threads.  The indent plunger and the shifter cam plate indent should now be in line.  Insert from the right side, the shifter shaft into the shifter quadrant.  It's a good idea not to depend on the shifter quadrant gear spring to hold in place during assembly of the cam plate bevel gear in proper mesh with the quadrant gear teeth.  THIS IS CRITICAL.  If the mesh is one tooth off, the forth gear shift will not be achievable.  Place a pair of visegrips on the shifter shaft so that the weight of the visegrip handle provides additional help to hold the quadrant in place while assembling.  Permatex the door area on the left hand engine case, using non-hardening Permatex.  You can now remove the transmission cluster and transmission door from the vise, and insert it gently through the opening, which requires an up and down manipulation, so none of the gears or cam plate is disturbed during this operation.  There is a 'feel' when the mainshaft assembly enters the right hand side engine case bearing.  Next, you will 'feel' the shifter fork shaft engage in it's bore, and lastly the layshaft entering it's bearing bore.  You can now, with a rubber mallet, tap on the transmission door lightly.  Do not tap on the protruding transmission mainshaft, as this will move the gears and rotate the cam plate, which is a no-no for proper tooth engagement of the cam plate bevel gear and the shifter quadrant bevel gear. 

Install two bolts in the transmission door, 180o apart, and tighten.  Now insert the cam plate spindle.  If the spindle does not fall home to it's threaded end, the cam plate bore is not in align.  Remove the cam spindle, and with a scribe, feel, and line up the cam plate.  The cam plate will shift into aligning position easily.  Reinsert the cam plate spindle pin.  It should align and fall into it's threaded end.  Screw the cam plate spindle home, and tighten.  Do not stake the spindle at this time.  Spindle staking is done after you're satisfied that the transmission shifts properly.

Tighten the plunger indent assembly.  It's now time to check and see if the transmission shifts.  While turning the transmission main shaft in the direction of rotation, go through the four gears and neutral, by turning the shifter shaft with the visegrips.  If all's well you'll hear the spring loaded pawl plunger clicking into the cam plate indent.  You should 'feel' when the indent is engaged, except for neutral, and if all's well, you should 'feel' a geared power transmission from the left hand mainshaft to the right hand counter sprocket spline shaft. 

You can now finish bolting everything together.  Use your Vincent Owners Handbook for transmission shifting adjustments.   Max Lambky  11/5/10

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:

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

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:

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:

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.

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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