Im getting a popping/grinding sound during take off. Upon inspection I noticed that the transmission sprocket seemed to be a bit loose. I removed the clutches and tightend the nut and it seems that there is still some play in the sprocket and main drive gear. I noticed no play in the shaft, only in the sprocket nut and gear assembly.

I suspect that the needle bearings between the trans housing and themain drive gear are worn. Does anybody know if this area should have play? And if not, Could these bearings be responsible for this noise?

The bike seems to shift well and the noise only happens during intial take off.

thanks,

 

If this went on for awhile forth gear splines might be beat up Time to replace forth gear and sprocket

 

Unless your running an open primary it sounds like you tightened down the Hub nut and that won't tighten the sprocket as it has it's own nut behind the inner primary, if the main shaft doesn't have any noticable play (sise to side and up and down) you may still have to tighten the sprocket nut. Only way I've found to do this is to pull the primary off completely due to the resess on the inner case that almost covers the sprocket nut completely, unless someone knows a better way that is. It's a pain to have to disassemble and reassemble so be prepared to replace any and all seals and gaskets while it's apart (might as well as it's apart and all), you may want to put a new sprocket on as well cause it's probibly gonna have more wear than you may be able to see till it's exposed. A tip on keeping that nut tight is to install a deadman in the sprocket, if the sprocket doesn't allready have threaded holes in it for a puller you'd have to drill and tap to make this happen. My sprocket has three holes allready, I was having the same problem (as well as other's) so while the primary was on the floor I scratched my head for hours for a semi perminant cure to the problem, so far it's worked out well. I used a 1/4" 20 x 1/2" cap screw in one of the holes that lined up on a flat of the nut, I had to grind the head of the cap screw (Allen head in case that's what you don't refer to these as) just alittle to allow it to be installed, put some lite loc-tite on it (not the nut) then backed the nut off till it hit the screw; it didn't take much.
I know it sounds like a lot of work but if done right it'll be worth it.

 

Allmost forgot the more important part, check to make shure you didn't pick up any water from that nut lossening up (don't laugh it can happen). I would recommend cangeing out the tranny oil anyway, you can see if there are any excess shavings in the oil which can indicate bigger problems. After finding the nut loose on mine and doing every thing to stop it from happening again I didn't bother chacking the oil, nothing was leaking so it should be good right? OOP's, started having problems with the push rod adjustment constantly changeing. Thought I must have screwed something up when reassembleing. Went through everything again, couldn't find anything obvious so I concluded the rod must have been weakened over the years and just couldn't handle the pressure any more. Pulled the kicker cover off to replace it and found the tranny full of water, no oil at all. Couldn't for the life of me figure out how this happened till I came to the realization that it must have entered via the tranny main seal due to the nut being loose allowing fourth gear to drift into the tranny (along with the spacer). So, hind sight being 20/20, do yourself a favor and change the oil out. The thing I was/am amazed with is it shifted fine, no clunking or grinding or wining, just had to constantly adjust the clutch. No shavings on the drain plug (magnetic tipped) so I don't know whether I want to flush/refill and run or pull the tranny and rebuild. My guts tell me to pull it but my *** tells me to run it, I don't generally listen to a-holes so I'm gonna pull it. Might see ya on the road this season.