Kachess
TY 4 Stroke Junkie
I replaced all my chaincase and drive bearings at 4000 miles, at the beginning of the year. I heard an odd vibration coming down the trail on my last ride so I pulled my chaincase dipstick and the oil wasn't clear like usual. I pulled apart the chaincase and all looks good except the outboard, upper, bearing was toast. Real sloppy and grindy. I've been running a synthetic gear oil. Bad bearing, bad alignment, wrong oil, any ideas?
Bob Miller
TY 4 Stroke Master
- Joined
- Apr 19, 2003
- Messages
- 1,322
- Reaction score
- 8
- Points
- 1,093
- Location
- New Milford CT
- Country
- USA
- Snowmobile
- Present Sled: 2011 Yamaha Apex 128
It sounds like the bearing had a defect or was damaged on the install 
RX1
Extreme
Make sure you have all of the shims on the jack shaft in place. There are TWO inner ones. My dealer lost the thin one and I had the exact same thing happen.
Kachess
TY 4 Stroke Junkie
I pulled a schematic off the internet and can't figure out which washers you are referring to. They must be outside the chaincase on the inboard side? I quess I ought to flush out the chaincase good to get rid of the metal filings. What do people suggest for a solvent?
Kachess
TY 4 Stroke Junkie
I lost the same bearing, again, after only anther 600 miles. The chaincase lower and upper inside bearings still feel fine (are tight). What's going on? The oil filled with fine filings (again) and the upper, outer, bearing is sloppy. The bearing is in the chaincase cover and I can't even imagine it is very heavily loaded. I am totally stumped.
RX1
Extreme
Sorry I did not see your last post. The schematic is difficult to read. It looks like the shim is on the wrong side until you see the line showing the proper relationship to the shaft. The shim I am referring to is just like a huge washer. It goes between the cir-clip on the shaft and the thick spacer. If it is not there, your whole alignment can be way off when the shaft is locked on the driven clutch side during assembly. Hope this helps.
