chaincase bearing

[Gibby]

I am trying to change my jackshaft bearing and lower shaft bearing after i pulled it apart I noticed that the lower bearing in the chaincase was also bad (it was falling apart)My question is the bearing had one side sealed and the other open, the part that struck me as odd was that the sealed side of the bearing was on the side that faces the oil and the open side of the bearing was facing the back seal of the chaincase, is this right? To me it seems like it would be the other way so the oil could enter the bearing, or should both sides be sealed?

Thank you

Gibby

 

[Snorover]

How meny miles and what machine???

 

[Gibby]

2005 warrior with 4400 miles

gibby

 

[doc 4 stroke]

the seal is on the chain side to help prevent larger debris cauased by chain, sprockets and reverse gears from entering the bearing surface area, causing premature failure. be sure to pack this area with high quality lubricant when replacing the bearing as it it takes time for the chain case lube to find its way through the seal

doc

 

[RobX-1]

Gibby, I noticed this too when changing all of my bearing and doing the jack shaft update last season. What I did was go to my local Napa store and cross-referenced the bearings with Napa brand ones. I read on this forum of others cross-referencing the bearings and getting them from someone other than Yamaha to save some money but if I recall, the cost savings wasn't that much. Most of the bearings had the same number of seals (e.g. on both sides, on one side, or none at all) but were basically the same bearing. Since it makes sense to have the seal on the chain case side to prevent metal shavings from getting into the bearings, it also makes sense to have a seal on the other side since it is exposed to the snow elements. I'll look this weekend for the actual bearings I used but the one I ended up replacing for the lower shaft bearing had seals on both sides.

 

[Honk]

Mine was only open on the inside. The bearing that replaced it was not open. asked dealer whats up? They said it wouldn't really matter, if it bugged me just take off the dust cover and then it would be open. My bearings were fine at 6 thousand miles, so it must have been getting plenty of lube.

 

[Sled Dog]

Personally I would put the open side to the oil and use a full synthetic oil. Every time I have changed oil in the chaincase there have been no large pieces of metal but only very fine minute metal dust particles that float in the oil. I am willing to bet that bearing would last as long or longer than leaving it to the elements makes no sense really.

 

[Gibby]

It is not at the elements because of the rear seal which holds the oil in the chain case which is around shaft on the inner side (bulkhead or frame side) of the bearing

Thank you

Gibby

This bearing was in the worst shape of all the bearings it had actually come apart, the jackshaft bearing and the bearing below that were pretty gummed up but still could have been rode further
(I will be replacing them all as long as it was apart)

 

[Sled Dog]

I see but like I said I am going to oil bath that bearing when I do mine. With no grease nipple it is the only way to go. That way I believe they will be the last bearing to go especially if you change your oil as soon as it starts to get dirty. I may opt to put a few holes in the seal as well or just take it right out so as to get the oil into the bearing. I have worked with chaincases all my working life on the oil rigs and all of the bearings are bathed in the oil lubricating the chain. The bearings always out last the chain and cogs.

 

[Gibby]

i was thinking the same thing to just remove both seals, do these chain cases have magents in them I know that my SRX had one on the end of the dipstick if i remember correctly and this does not, I have not looked for a magnet yet so I was just wondering

gibby

 

[Sled Dog]

One should be able to get a magnetic drain plug.

 

[RX1-er-2005]

Just drill very small holes in seal on the oil side, like 3 on a even pattern like top, bottom left and right...it doesn't take a large partical to scr!#-up a bearing and once you do it'll HEAT up real fast...

The other thing use a good quality oil Syn. or Mineral and change frequently...not that once a YEAR thing.I usaully try changing it every 1000kms/600 milles, just think what it cost for peace of mind, you've got a lot of power concentrated in 1 area that only holds 250ml...

Just my .02

 

[Sled Dog]

I only change my oil once a year and I do use synthetic. I have yet to see a large chunk of anything in all my chaincases with all brands. All that ever comes out is a grey oil. Grey because of the powdered dust metal that ends up in all chain cases and is suspended by the oil.