Triumphrat

black&chrome

Hi all,

after rebuilding the gearbox and bottom end of my 1976 bonnie there is still one problem I can't seem to shake. The primary sprocket alignment.
it was out enough that the only way to get them true was with a big stack of shims on the front engine sprocket. just at the max that triumph allowed for. after the rebuild it seems even worse.

I have entered a post in the past about one of the bearings being proud in my main shaft - keeping the dogs from properly engaging and possibly pushing the clutch basket out - but even with this rectified no improvement.

So, I rationalized... maybe order of tightening could pull the mainshaft from one side to the other? I did do the rear sprocket up before the nut on the otherside of the gearbox. I also did the nut up for the crank pinion first which would pull in the opposite direction worsening the problem.... only that would imply huge crank float - which didn't seem to be the case at all.

could it be something this easily overlooked??

there was also one aluminium spacer in the gearbox which wasn't in the parts diagrams that i removed - may have been making up the difference on the layshaft to compensate for the proud bearing I suppose? Anybody else have a aluminium spacer anywhere in their 'box to their knowledge?

I also had a bad run with a few clutch centers being poorly machined - off centered tapers and I wonder if perhaps it's something as simple as perhaps it hasn't been machined deep enough - yet it's the same one that came off that was (with the shims) aligned.

please write if you have any suggestions which could see me riding again a little sooner

cheers

leif

Webby

Hi Leif,

I posted a reply a few hours ago, but it's disappeared! So here it is again!

I find it strange that you have an aluminium spacer in the box, I think that normally in a gearbox the spacers etc. would be steel or bronze.

Regarding the sprocket alignment, I have no idea! But did you replace the mainshaft bearing? Maybe it needs tapped in a little further, or is slightly thicker than the original. The other possibility could br the clutch centre, you could make sure it's a good fit by smearing a little valve grinding paste on the taper and turn the clutch centre a few times to make sure they fit together correctly. Or as you say possibly dodgy pattern parts.

This probably won't help, but good luck, hopefully someone out there will have the answer

Webby

black&chrome

i replaced the roller bearing the timing side - but not the primary side one as it was in perfect shape. was it seated completely? well there is no reason it should have moved from it's existing seat when dissassembling it right? good thing to watch for tho'.
thanks

thirdbike

Sounds like something isn't assembled correctly. You are sure that the clutch basket is properly seated?
The rest is hard to tell from your description. A couple of photos might help

jimmy bush

Was the new timing side roller bearing as wide as the old one?

black&chrome

Same bearing - and the cases went together without a problem. Just tried to shim it out to see exactly where it was at - and it isn't any different than it was. .155" of shims. It just looks rather far.

like the triumph book says .03" (up to four) and .01" (up to four) giving a total of .16" max. so I guess its acceptable.

that said - the 'aluminium' washer in the gearbox turned out to just look that way - stuck a magnet on it and, er, it stuck. Looks like it should be behind the kickstart spring after all... ****. since the kicker is still jamming up occasionally even with a new pawl, i may have to try and modify the leading tooth - with a grinder.

any one have success doing this - other cures???

thanks