1992 YFM 350 Big Bear needs help
 

I inherited this machine and put a couple hundred bucks in fixing the seat and cosmetics. Because of its size it's great for deer hunting and I really like the low range lock 4WD. I rode it for a couple years and the left rear seal and bearing disintegrated and also ruined the splines on the axle. Shop says $1,200 to fix. Ouch. Too much for this old machine. It looks like the whole back end of this machine comes off with about six bolts. Frame, wheels, diff, axle, the whole works. I've tried to find a parts machine but not having much luck. How can i find out which other Yamaha models and years would have the same back end?

Yamaha are always changing rear axle and brake designs. The rear axle splines are the most common cause of the bikes being scrapped, so finding a good rear end is almost impossible. Because they changed the rear end so often nobody bothered making aftermarket axles either, so it was Yamaha parts at Yamaha prices. However a few years back someone came up with welding round the spline area and re-machining the splines on your axle. Then a CNC machine shop decided to make complete axles from bar, once they had the program for each axle, they just set the machine off and make one to order. It is in Salisbury UK, however I would think someone in the US would be doing it too. It was a Yam dealer who told us about the Salisbury one. The crown wheel needs to be in good order though. The machine shop got us to send it, so they could tweak the spline size to suit the wear on the crownwheel.

Thanks merryman. I was afraid of that. Just located same YFM 350 machine for sale that has some other issues. Needs battery, carb, ignition. Maybe I'll be able to buy it and use one machine for parts. I have no idea what these old machines are worth. Seller is asking $1,150. Would it be insulting to say I'm looking for a parts machine and offer $600?

No idea of US prices, but I wouldn't pay much over £450 for an early 90s non runner.

Check part numbers for what you need to switch over on partzilla . com first. And for the yfm 350 $500 for a running one is common price 2wd and slow does not sell. No idea where you are but check on fb marketplace or ebay you will find one. Just make sure you know the years of the machines that are compatable. I have 3 87 moto 4 350's and am able to swap out rear dif's but I think in 89 they switched axle diamiters. Do research and be patient