chain case bearing??

[jayman54]

in my 98 srx i did the bearings in the chaincase last year and and the top bearing was seal on one side and the seal was facing the inside leaving the back open on the outside... i figured this would be wrong and put the new one in with the open side facing the chain so it would get some lubrication(makes sence to me)...i was told later that the seal is supposto be on the outside...which is right?? doesnt make sence to have the open end on the outside where shit can get to it...and i cant remember if the bottom one was sealed on one side or both or which way i put it...the reason is i checked my fulid before i took it out yesterday and it was very gray and the magnet looked like a big catapillar....any ideas i'm gonna pull it appart again which is a pain in the *** at the moment

 

[greg]

This has been talked about many times with two different opinions.
The service manual states:

A. Make sure that the bearing seals face towards the
drive chain as shown.
B. Properly install the rubber seal onto the drive chain
housing, making sure that there are no gaps.

Hope this helps.

 

[jayman54]

i'm almost tempted to just run a double sealed bearing....i dont like the idea of running an open bearing with nothing to keep it lubed...has anyone had problems runningit with the seal facing out or running a double sealed bearing...

 

[daman]

As far as crap on the dip stick thats normal, your going to have that
on any sled, it's doing it's job and collecting the metal particals out
of the oil,if your oil looks gey it's ready for change.

 

[jaydaniels]

I always wondered this myself and I believe I may know the answer. If you look where the jackshaft goes into your chaincase, on the back side you will see a spacer that goes up against the inner side of the bearing. This spacer has a rubber seal on the inside to keep chaincase oil from escaping between it and the shaft. Having said that, I believe it is possible for the oil in you chaincase to pass between the bearing inner race and the drive shaft into the space between your driveshaft seal and the backside of the bearing. Since the seal is out of the bearing it is able to lubricate the bearing. The seal on the driveshaft keeps it from leaking out. The reason they keep the seal in on the chain side is to keep out metal pcs which collect form wear on your gears and chain. The metals pieces are too large to pass between the inner bearing race and the drive axle. It almost acts like a filter and allows the bearing to be lubricated from the back side. This is my theory anyway. Could be wrong but it is the only thing that makes sense to me.

 

[daman]

The reason they keep the seal in on the chain side is to keep out metal pcs which collect form wear on your gears and chain. The metals pieces are too large to pass between the inner bearing race and the drive axle. It almost acts like a filter and allows the bearing to be lubricated from the back side.

Good thought,, but thats what the dipstick is for...

 

[gild]

pack it

Like Jaydaniiels says, keep the metal filings from chain and gears away from brgs. Collar and outside seal keeps moisture out and if in doubt about lubricating brg , Pack it with grease.

 

[Ding]

Good thought,, but thats what the dipstick is for...

Every chaincase I have torn apart that had the bearing seals removed on the chain side had metal shavings in the bearings. The problem is that when the pieces fly off the chain, they do not know that they are supposed to go directly to the magnet on the dipstick. Instead they fly around for a bit, and only go to the magnet when they get to the bottom of the cases. It is simply a matter of lack of direction . . .



I have also torn a few apart that had both sides sealed. A couple of these were dried out and were also failing or already failed.



I tend to believe that the seal on the chain side only is the best approach.

 

[daman]

Every chaincase I have torn apart that had the bearing seals removed on the chain side had metal shavings in the bearings. The problem is that when the pieces fly off the chain, they do not know that they are supposed to go directly to the magnet on the dipstick. Instead they fly around for a bit, and only go to the magnet when they get to the bottom of the cases. It is simply a matter of lack of direction . . .



I have also torn a few apart that had both sides sealed. A couple of these were dried out and were also failing or already failed.



I tend to believe that the seal on the chain side only is the best approach.

Hmmm....i've never experienced that all mine even the oil iron with no D/S
or seals never has iron issues ,then again i change out evey two seasons
and thingsare very clean inside,almost waisting my time..

 

[Ding]

The chain throws off tiny little pieces of metal under normal use. You should look at your used chaincase oil under a microscope next time you change it. You just might be surprised. That discoloration that you see in the oil is actually small metal fragments.

It looks fine to the naked eye (except for what looks like discoloration).

Changing bearings every 2 seasons is one way to combat premature bearing wear.

 

[Old Thumper]

I believe that when a bearing only has 1 side closed it is call a sheild rather than a seal. A sheild is there to keep particles from getting into the bearing, but it will let oil pass through. In a chaincase there is a seperate seal that goes in behind the bearing. So the bearing is installed with the sheild toward the chain to keep metal particles out, but the chain case lube will go through the sheild into the bearing. The outer seal will keep the lube from leaking out.
Make sense?

 

[mrviper700]

post number 5 is exactly right, the seals on both the jackshaft and driveshaft mounted in the chaincase itself is what keeps the oil in there for the bearing, the seal or shield on the chaincase side is to prevent large metal peices from seizing the bearing, the oil will still draw thru the seal from rotation, the oil will be drawn in the bearing in the slight gaps between the seal and inner race. This was argued on here and I offered a simple test you can do at home to see what the fact is. Take a old chaincase bearing or any sealed bearing and completely dry it out with carb cleaner or whatever, and then mount it in a vise on outer race, place the seal side up towards the top, and unsealed side down. Now get some oil and a drill, find a drill that will bite into the center hole/race and begin to spin the bearing, now apply small drops of oil at the seal/center race, watch how the oil is drawn in and will lube the bearing, end of argument. I kinda always chuckle on this one because people always think they can out engineer yamaha and build a better sled, you dont think they have already thought of all this? Anyways, try the test, you will see for yourself.