69 T100s Problem is jumping out of 2nd gear under hard acceleration and also 4th gear but less often. I took the gearset out expecting to find badly worn dogs and camplate but they are not really that bad. I've been playing with it all afternoon to try and figure out the cause but so far I've been unable to make a positive diagnosis. I'm lucky enough to have a 2nd gearset from a 70 model that I THOUGHT was in great shape but after comparing the 2 sets side by side I would say that the dogs on the 69 are in better shape than the 70. What I HAVE noticed so far... The engaging dogs on the layshaft that get pushed by the outer selector fork only push those dogs in about halfway into the 2nd gear on that layshaft. I swapped camplates and forks without helping any. If I push up on the 3rd gear that carries the 2nd gear dogs then engagement is full. Would this account for the problem? The 70 gearset seems to get much deeper engagement. What do I do to increase the engagement? Does this describe things very clearly?... Tough to describe such things!
Another issue I have is again with the layshaft. The 2nd and high gears come as an assembly. On the 70 set the high gear is a tight enough fit on its shaft that it does not move... But on the 69 set the high gear is loose enough that it slides just a little bit away from the 2nd gear. Between these 2 gears is a 2 piece shim. You shouldn't even know its there but on my 69 set, when the gear slides forward a bit, this shim falls out and is a bear to get back in place! Once the gearset is back in the bike I doubt if the gears would be able to move enough to allow this shim to fall but should I do anything to lock the gear better on the shaft anyways??
Final question for now... I ordered new springs for inside the gear box. The camplate plunger spring I received is 1/2 inch shorter than the stock one but seems a bit stiffer. Could this be the only issue with jumping out gear? A weak plunger spring? Is this shorter spring the recommended replacement? Like I said... Gear dogs dont look too bad. Camplate has some grooving along the edge but doesnt seem to have too much total wear. Selectors are not discoloured or too beat up looking. I hate to throw money at a problem without knowing the actual problem but dont mind spending money on something I KNOW is worn. Any 500 gearbox gurus out there to help me?? Colin
I suggest comparing the free length of the plunger spring against the factory spec and be suspicious if it doesn't match within an eighth of an inch or so. The proper plunger spring can be packed with a ball bearing of suitable diameter placed inside the plunger to increase the pressure.
Make sure that the right mainshaft bearing is tight in the case. This one can drift from wear and cause strange symptoms like the clutch lever free play changing while you ride once warmed up.
I had a jumping out of 2nd gear problem but packing the plunger spring along with a custom layshaft thrust washer that's thicker than original to tighten up the layshaft endfloat cured it. Also, I don't run gaskets between the cases. Gaskets aren't speced in the parts book and adding the inner one increases layshaft endfloat.
"Beer is proof that God loves us and wants us to be happy" - Benjamin Franklin
The fiting of a ball bearing under the plunger spring, is actually mentioned in Triumph tuning info. Gaskets are fitted to SOME 500 gear boxes, and in some of the 500 gearboxes I've taken apart, there have been shims on the layshaft. I've not been able to explain this up until now, so hh, you have probably given me some idea. I'll check with a vernier next time.
The camplate plunger spring I ordered was 57-0373 but the part I received was 57-4459. The package says "57-0373 Use 57-4459." I wonder with this shorter spring if I'm supposed to use some sort of spacer like you've metioned or leave it as-is? It does feel like a stiffer spring when I compare the old "longer one" with the new "shorter one". I rummaged around and found a suitable "spacer" for the layshaft that I will trial fit to see if I eliminate most of any free-play between the thrust washer and the inner gearbox cover.
Well I spent some time and now have a .010" shim for the Layshaft that brings end play down to about .015 - .020" (estimated) - It "feels" good now. I went through my parts basket and found ANOTHER camplate plunger spring - Off a 70 T100... Free length is the specified 2 1/2" but it has 25 coils compared to the 22 specified plus it seems to be a heavier gauge wire than the one I pulled out. Its stiffer than the original. I really see nothing wrong with the Camplate wear areas but will sleep on the decision to change it or not one more night. Otherwise, I think I will slap it back together tomorrow night. If its no better next spring, what the heck, I will do the job again. Pulling the clutch is the long part, the gearbox seems pretty easy now after doing R&R on it a few times to test things. Cheers.