CL009 CLUTCH

Why is my VMT gearbox stiff and reluctant to change gear ?
From first into second , second to third the lever requires much more pressure that I expect , sometimes it doesn't want to go at all from 1 to 2 .
Downward I have to be very positive and deliberate , and have difficulty finding neutral on the move .
I've had the box apart several times and checked the selector action with the gears out .. it's free and easy.
I've fitted new selector rods and indexing pawl, bearings are all good.
At rest the change goes through the box positively.
I recognise that the linkage gear change lacks leverage and is heavier operation that the standard lever, my clutch is not dragging ( I can hold the bike easily with the clutch in), nor is the clutch fouling the primary chaincase on full lift, primary chain isn't over tight.
I'm out of ideas any suggestions? Missing those slick , quick changes is spoiling the pleasure. - Alan Lawrence 23/4/2002

You've covered most factors, but I would be interested to know if you can go relatively easily into second, then third, and back whilst stationary (with the engine running, and possibly needing to move the bike a bit so the dogs can mesh). If not, then I do think the most likely cause is still clutch drag.
If you can change fairly easily when stationary, but not when riding then it's just possible that the gearlever or the operating arm on the outside of the gearbox is binding.
I once adjusted the gearlever's bush so there was none of the 'slop' that soon develops and feels wrong; and I made sure the arm on the end of the shaft was right up against the bush in the end-cover. I thought it would give me a more precise change, but it stiffened the change just as you describe, both upwards and downwards. It seems a bit of slop is needed.
We'll see if anyone else can suggest anything. - TW 23/4/2002

I've just come in from another ride around the lanes and am still having difficulty with upward and downward changes .... all the symptoms of clutch drag , it's as though I have to pull it in to gear without a clutch , even could not get out of 4th on one roundabout with the clutch lever full in . But at stand still with the lever in the clutch frees up nicely with the lever right in . To get into first I have to roll the bike forward a little and snick it in as the revs drop to minimum , otherwise it grates ... but all Velo's only go in at very low revs , upward changes are better than down ( there again you can do these without a clutch at all if you are careful) . The clutch is new ( bonded plates) . There are no grooves in the chainwheel to trap the plates I've shimmed or made new parts to take ALL the slop out of the gearchange , it operates freely in the case with no gears in the box and travels fully ( I did have a problem with the twisted metal link being initially being misaligned, and it jamming due to a previous owner repair changing the rivets for nuts and bolts , and the indexing pawl was not picking up 4 th correctly ) I changed the twisted metal for a link set up as the early 12 boxes . I tend to agree with you it has all the signs of clutch drag . Maybe I should back off the adjustment and live with a little slip until the plates bed in ? Alternatively maybe I haven't got the spring compression fully up tight so when I see slip it is basically inadequate pressure and not plate contact that's the cause. ... I'll have another play with it tomorrow. - Alan Lawrence 24/4/2002

I'm interested that you have taken all the slop out of the pedal mechanism. As I said, I did that and concluded that the remote gearchange actually needed some slop, plus the internal transfer mechanism does as well - e.g. the rod from front to back in the end-cover needs a bit too.
Perhaps as an experiment, back everything off so it is sloppy again.
If no difference, then... try pre-loading the cable/thrust bearing so there is a ridiculous amount of clutch movement, again just as a test - though if you have an adjuster under the tank you may need a push start, since the kickstarter will probably slip. - TW

I've re read all the clutch drag questions on the Q&A and gone through the adjustment drill again .
I've noted the following ; On the stand with the engine running and me standing beside the bike to change gear , it goes through the changes up and down , if a little stiffly ( probably due to leverage and my standing position .) If I take all the slack out of the clutch cable .. and then a few turns more to preload the clutch bearing , on the kickstart , the clutch lifts and the plates are really free...., better than before. With everything set , the clutch is just lifted free when the lever is against the grip. The spring holder is screwed fully home so pressure is OK. The handlebar lever pivot radius is 1 1/8" ( the old original lever I took off was much less ) so I have plenty of travel at the lever. There is movement in the clutch wheel / output shaft when the clutch is lifted , I can see the final drive shaft move ( flex) forward and back as the clutch is operated...... Sleeve gear bearing worn/lose ? ( it looked ok when I had the box apart but I didn't take out the bearing.... big mistake )
My conclusion ; I'm probably losing some operating movement on the clutch due to the worn bearing allowing the assembly to move , especially when things get hot and expand . There should not be this movement so I need to look at /change the bearing . If I open the box then I will put some slop back in the linkage .( can you get oil with slop included ? ) I will try on the road again after this mornings adjustments , then try with a 'reverse pedal ', then major surgery to remove the 'big lump' for dissection will be next . - Alan Lawrence 25/4/2002

You are certainly tackling the problem methodically.
Don't put any slop back into the internal linkage just yet if it means removing metal - all I meant to recommend at this stage would be loosening the two ends of the external mechanism on their shafts laterally (just by loosening the footrest nut and by moving the lever at the gearbox end out a fraction on its shaft so that no way could they be binding laterally, and check the gear lever was also nice and free to move up and down. In other words, no chance of stiffness outside the box. And if you have a reversed lever that would be an even better test. You also need to make sure that the end nuts that are the bearings for the fore-and-aft shaft in the end cover are not crimping the shaft. I do think if any of the above 'bind' it makes the gearchange stiff when moving.
It seems you have ample motion for operating the clutch, and if you can see the outer plate moving well over 1mm then that should be enough.....unless the backplate is also moving out at the same time.....which indicates sleeve gear nut or bearing problems. First though -
Some of your comments puzzle me, so let's explore them: (it sounds like you have the proper Velo clutch lever now)
>>>If I take all the slack out of the clutch cable .. and then a few turns more to preload the clutch bearing , on the kickstart , the clutch lifts and the plates are really free...., better than before. With everything set , the clutch is just lifted free when the lever is against the grip.
It sounds like you have borderline lift when the clutch is adjusted 'properly' - you really shouldn't have to come right back to the bar to get it feeling "really free". Do try riding with it quite preloaded, if you can start it, and if the change is now better, we know it is a drag problem.
>>>The spring holder is screwed fully home so pressure is OK.
I'm not sure what you mean by this - the spring holder just moves in and out to adjust the clutch - it never goes "fully home"?
>>>There is movement in the clutch wheel / output shaft when the clutch is lifted , I can see the final drive shaft move ( flex) forward and back as the clutch is operated...... Sleeve gear bearing worn/lose ? ( it looked ok when I had the box apart but I didn't take out the bearing.... big mistake )
The clutch wheel (assuming you mean the chainwheel) has to move - that's part of the design of the clutch - it's the fourth plate of a 9 plate clutch, so it moves 4/9ths of the total movement of the clutch. The output shaft (assuming you mean the mainshaft with the final drive sprocket on the end) shouldn't move, unless there is a problem with the bearing/circlip in the gearbox end-cover. If you mean you can see the sleeve gear nut moving in and out, then that does mean lost motion, and is usually because the sleeve gear bearing is worn out or, more likely, loose in its housing. More often it is the backplate that moves in and out a little because the sleeve gear nut isn't dead tight. Either of these must be fixed. However, the sleeve gear bearing is only a single-row ball bearing so a tiny wobble is unavoidable. But if you can move the whole clutch by hand in and out enough to notice it, and the sleeve gear nut is dead tight, then the sleeve gear bearing or its retaining ring needs attention.
Do keep on testing & report back. - TW

I've just come in from a test ride on the VMT after stripping and reassembling the clutch very carefully ,everything is now working as I expect and no drag or slip , gearchanges are smooth and easy once more ( even with the VMT linkage ). I think the problem has been the clutch .
To recap, in my rebuild I had changed the plates to the club friction plates , fitted new plain plates, the roller thrust bearing from the club and fitted a new clutch cable .
- When I stripped the clutch ( though I had only done about 60 miles) , the inner two friction plates show no 'dirt ' or 'discoloration' on the friction material , they were 'as new ' ,which I interpret as they have not been rubbing ( separating ) the outer one had obviously been functioning and doing the work . - There was some 'gold paint effect ' on the inner primary chain cover below the thrust bearing ( rubbing cage ). - The sleeve gear spacer was very tight on the sleeve gear ( I had to' tap it' in place when I assembled the clutch the first time .
When I reassembled everything I have checked for free operation of the mechanism from the handlebar lever at every step and made sure that;
The ' frying pan' is shimmed correctly on it's pivot ( it was ) It does not foul the sleeve gear retaining ring as it lifts , or on as much lift as I could generate by taking up the cable adjuster ( it can do if the bearing has been changed and the slots for the removal tool have burred the ring grooves) . The clutch chainwheel is free to slide on the back plate ( mine was tight so I 'polished ' the surfaces to remove any high spots ) That there were no burrs in the backplate, no matter how small, to prevent the friction plates sliding . I made sure that the clutch thrust bearing was free on the sleeve gear spacer and did not foul the frying pan causing misalignment in lifting ( this is where it had been rubbing to produce the 'gold paint ') That the Thrust bearing was free to centralise in the frying pan so that it presented a square face to the clutch back plate irrespective of the angle of the frying pan as it arcs in operation . For good measure I fitted some new thrust pins. I cleaned up the spacer intrernally with my dremmel and some fine wet and dry so that ot went home against the sleeve gear bearing more easily . After going through the clutch adjustment 'drill ' I took up all the slack from the cable until I could feel the thrust bearing just begin to be loaded . The clutch now frees at about half lever travel and does not slip or drag . ( I also fitted my lip seal instead of the felt while I was at it )
I suspect the clutch drag had been caused principally by the clutch plates not sepatrating correctly ( only the chainwheel and outer plate lifting ) , maybe aggravated by the possibility that the spacer was not tight back against the thrust bearing ( if this were so the system would need more lift to operate and this could give rise to the slight movement of the clutch in the fore and aft plane that I had observed , and finally a new cable taking up some lift through compression of the outer . - Alan Lawrence 3/5/2002