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Removal of Chaincase Side Bearing?

Sevey

TY 4 Stroke God
Joined
Feb 15, 2011
Messages
1,740
Location
Collingwood, ON
Website
www.ty4stroke.com
Country
Canada
Snowmobile
2018 Sidewinder RTX
Hey Guys,
I have never had the chaincase apart to remove the drive cogs.
Is the main bearing at the bottom of the chaincase assembley a sealed bearing or is it lubricated by the oil in the chaincase?

How many km's should you expect to get out of it?

Thanks
MS
 

Sealed bearing. Changed mine at about 24,000 kms, even though it was still good. Replaced it only because was swapping out the driveshaft for one with extrovert drivers. So I changed both driveshaft bearings since I had everything apart. However, the driveshaft bearing was done on the clutch side, and I greased that one every year by removing the seal on it.
 
So you got really good mileage from your bearing. I am just debating at what point they need to be done?
I have 11k on the sled so it should be fine for awhile.
Thanks
MS
 
I'm pretty sure the bearings in the chaincase are not sealed and they are lubed by the chaincase oil. There is a separate seal that presses into the chaincase housing and seals around the shaft. In any case, the chaincase bearings normally last longer than the left side bearings because they are not exposed to the elements and some people don't lube the left side bearings often enough. Typically the Speedo bearing will go but you can change that without removing the driveshaft. When the jackshaft bearing goes everything has to come apart so you might as well do all of them. See picture- red is seal and blue is bearing.

Edit: added image
 

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YammyRX1 is correct. Chaincase bearings are a mixed bag however. Some are open sided with no seals in the bearing itself, others have a seal on one side of the bearing. As long as the chaincase oil stays free of metal filings, and the driveshaft and jackshaft run true, the bearings in the chaincase should last for a very long time. That being said, if you have the chaincase apart, it might be good time to replace the bearings on the jackshaft and driveshaft. There are also bearings pressed into the outer chaincase housing which I did not replace as they felt good and I was not familiar on how to change those out. If you have reverse on your sled, you need to make sure that when you put the chaincase back together, that the tynes that engage the reverse gear must be on top, not from the bottom. You will see what I mean when you put it back together.
 
On mine, the upper is an open bearing and the lower is sealed. I purchased a tool from Ulmer to remove the top nut holding the gear on. $35. I'm replacing all 4 bearings since I am dropping a tooth on the top gear.

I'm also replacing the chaincase cover bearing. Mine was a bit rough. If you heat the cover it will tap out with a hammer.
 
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Does anyone know why the bottom bearing is sealed on one side only? I tried filling it with grease and using a shaft I made to fit the hole force it out with the grease but all that did was push the seal out, ended up making a puller quite simple to remove! Not a good idea to heat the chain case cover!
 
I replaced the complete chain case bearings and seals every 9000 km which was every 2nd year, Blind hole puller comes in real handy for bearing in the outer cover. Remember to always press or tap on the outer race only when installing bearings in the chain case halves. Freezing the bearings overnight helps a little also.
 
Does anyone know why the bottom bearing is sealed on one side only? I tried filling it with grease and using a shaft I made to fit the hole force it out with the grease but all that did was push the seal out, ended up making a puller quite simple to remove! Not a good idea to heat the chain case cover!
I have done this job quite a few times. The bearigs are sealed or only sealed on one side. They are lubricated by the chain case oil. Most of the time the new bearings you put in are all sealed some are open on one side. It doesnt really matter they all get lube one way or another.
 
I have done this job quite a few times. The bearigs are sealed or only sealed on one side. They are lubricated by the chain case oil. Most of the time the new bearings you put in are all sealed some are open on one side. It doesnt really matter they all get lube one way or another.
To get them out i just remove the outer seal and take a socket a little smaller than the bearing and bang the bearing out same when replacing
 


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