Chain case bearing and seal

brethren

brethren

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Joined
Apr 6, 2012
Messages
164
Age
58
Location
Markham Ontario
Hi guys I decided to replace my track at the end of the season. After ripping into it I noticed a bunch of other parts that need replacing, so they are on order. I've been waiting so long for my parts, I'm not sure of a couple of things, and any help would be greatly appreciated.
The chain case bearings had one seal removed. If memory serves me correctly it was the side facing the back of the chain case?
The other question is how deep to push in the chain case seal, does it seat up against the chain case bearing?
I wish I had taken pictures 😢

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Maybe a few pictures will help spark a response
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seal goes inside and will be on backside of case. open side is inside. and yes you should see that seal flush against the back of case. 3:16x (yammie tony)
 
Thanks Yammigod I would have put the bearings in the wrong way. So I'll put the bearings in this way.

Here is a picture of my home made sprocket press for your entertainment.
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Too late, I drove it in yesterday seal side to the back of the case, open side to oil. I remembered it the other way around but looking at the jack shaft bearing on the cover, that one is wide open. I don't think it's the end of the world.

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it goes the way you did it. i just checked three i have. the two seals top and bottom go to the inside closest to the tunnel. this seals the case from anything for sure leaking. 3:16x (yammie tony)
 
YAMMIEGOD3:16 said:
it goes the way you did it. i just checked three i have. the two seals top and bottom go to the inside closest to the tunnel. this seals the case from anything for sure leaking. 3:16x (yammie tony)
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Not it that it matters as this has been a debate here for a while. As you I have tore down a million chain cases and everyone of them has seal towards the oil? Maybe the vipers, vmaxx's ive worked on are different then the SRX? From the factory seal towards oil. But run it how it is I think guys been running both ways without problems for a long time!
 
sorry bud. i disagree. i have three in my shop. two blow,in apart from grass racing off my 2000 srx i bought new. that seal goes on back side. INSIDE against tunnel but its summer so whatever. 3:16x (yammie tony)
 
Brethren,

Super has you on the right track. The pictures in post #6 looks correct to me. I posted the link again below. The chaincase metal will shorten bearing left if open to oil.
http://www.totallyamaha.net/forums/...nstallation?highlight=Chain+case+bearing+seal

Also Mr Viper has a good explanation from 2007.

mrviper700

by leaving both seals on the bearing it will fail sooner then later, the small amount of grease that comes in them wont make it as long. It will become hard and wad up between the bearings and then starve the bearing for lube, same exact way the idler wheels will do without any care given to them each season.The reason the seal is off on the inside is to allow the puddle of oil that will accumulate between the outside chaincase(closest to the jackshaft and driveshaft)seal and the space in betweeen to lube the bearing, there is a extra seal on the upper and lower shafts to shield the outside snow/dirt on back of chaincase. This is why both your jackshaft and driveshaft have a special spacer on them with a o-ring seal and this spacer resides in the inner seals both upper and lower. The seal on the chainside obviously keeps the large metal peices from chaincase from contaminating the bearing. If you spin a bearing in oil when its bone dry the rotation from the bearing will draw some oil thru past the seal, the small area in between the chaincase inner seal and the bearing width to chaincase side bearing seal is what will keep the bearing alive and lubed with chaincase lube.
 
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Two years ago I disassembled my Ventures chaincase to change my track and bearings too. My sled still had its original track and bearings at the time. To my surprise both my chaincase bearings seals on the track side where removed, and on the chain side the seals were still in place. It makes sense that it prevents all the metallic crap from contaminating the bearings. Though even after Mr viper explanation, i still can't see how oil reaches the bearings, but it clearly does.
 
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this post drove me nuts the more i read it. i blew two chaincase on my srx. one on ice and one on grass. now than i through a good used chaincases on my sled both times . both times the bearing were exposed to the fluid in case. now am i wrong, who the hell knows. i guess you go with what will work best . 3:16x (yammie tony)
 
Agreed^. Every Yamaha chaincase From 1992- 2002 I've worked on the bearings were exposed to chaincase oil. Seals on outside
 
Oh boy I didn't mean for this post to end up this way. Thanks for sharing both trains of thought, both have good points. I think it's upto the individual to come to their own conclusion. I'm pretty sure somewhere in Yami engineering department the same discussions have taken place. I kind of like the open to oil concept because, any nasties should get caught by the magnetic tip of the dip stick. Also yearly oil change should keep things clean.

Sled is back together and stored for the summer. Now is dirt bike season, but there is one part of me wishing for a snow storm. This will be my first track installed and I can't wait to see the difference on the trail from stock.

Thanks again for all the input, cheers.

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I did mine recently as well. I purchased an aftermarket bearing kit. It had seals on both sides. I left them both in place. When I removed the jack shaft I realized the bearing was bad. If memory serves me right. The seal was only on the gear side. Good thing I thought to myself, because the bearing would have sent a lot of metal through the chain case.
 
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