Need some help on my 1984 big red flywheel keys shearing.

[Fourwheelhorse]

Hi guys,
This has been a struggle, I got this bike for a descent price.. I got it non running. Anyhow, I done all the normal things, checked spark, cleaned tank and carb, bought a new battery and then it would turn over, so I checked starter it was fine, checked all the normal things.. then I pulled the stator side of the engine off, and seen that the shaft that has is labeled “ starter reduction gear B” had the geared washer and the circlip out of place they were pushed all the way to to the front of the shaft. Anyhow, I replaced them and carefull reinstalled the side cover and it fired up like a champ, then it died. It sheared the flywheel key, so I pulled it back apart and was looking everything over and noticed the geared washer and circlip were pushed back up towards the middle of the shaft again. Anyhow, I removed the flywheel and the starter driven gear along with the needle bearing and noticed that behind that gear was two thick washers.. the book doesn’t mention those anywhere, so my question is this, would that be my cause for my shearing flywheel as it done it two times on me so far. Has anyone here had this issue? Any and all advice is welcome! I can’t download pictures for some reason or I would..

[Fourwheelhorse]

Update… I also noticed there are two large washers behind the starter gear that’s behind my flywheel. According to the manual, it should only have one and the chamfered face is directed toward the flywheel. Funny enough, there are no pictures in the diagram of the collar, as it’s called. It’s just mentioned one time in the manual. I removed to second washer and hopefully that will allow the flywheel to seat further back onto the crankshaft.

[MrConcdid]

I have seen this happen once before, double check your timing, if its off too much, it can run but will detonate and sheer keys. Yes 1 shim per the instructions, also its a half moon key, make sure the arched part is in the crank and its flat across the top when you slide on your flywheel, also I lube the crank and make sure the flywheel goes all the way on, if its not fully enguaged it could sheer keys.

Good luck, the 84 is a great machine.

MrC.

[Fourwheelhorse]

Thanks for the advice and reply! I still think you should do a YouTube video on the subject.. =

[JustEnough]

A racing engine builder told me to lap the flywheel to the shaft with valve grinding compound and that once they are matched from that, the key is hardly needed because the flywheel has so much grip on the shaft. It worked for me.