bluelightning
New member
hey all
you've all been very helpful to me in the past, and once again, i am in your need lol.
if you read my other thread, you know about the whole thing where i was getting a horrible clanking.banging out of the chain case. got the cover off today, and was greeted by the head of the bolt holding the bottom gear on falling right out. and i thought that was the noise...HA! sure enough, removed the bottom gear (hey, at least i didnt have to loosen it!) and a whole bunch of loose ball bearings decided to join the party!!! any ideas on what would cause this bearing failure? and given the fact that i am already in there...how hard will this be for me to tackle? anything else i should look for while i'm in here?
FYI, dont know if you remember, but when i first got the sled i was having speedo issues.....wondering if this contributed to that, or vice versa? the bearing on that side was fine.....
you've all been very helpful to me in the past, and once again, i am in your need lol.
if you read my other thread, you know about the whole thing where i was getting a horrible clanking.banging out of the chain case. got the cover off today, and was greeted by the head of the bolt holding the bottom gear on falling right out. and i thought that was the noise...HA! sure enough, removed the bottom gear (hey, at least i didnt have to loosen it!) and a whole bunch of loose ball bearings decided to join the party!!! any ideas on what would cause this bearing failure? and given the fact that i am already in there...how hard will this be for me to tackle? anything else i should look for while i'm in here?
FYI, dont know if you remember, but when i first got the sled i was having speedo issues.....wondering if this contributed to that, or vice versa? the bearing on that side was fine.....
800
New member
the bolt came out first, then ya lost the oil and waisted the bearings, did you pull the case out and see if the bearing spun in the case??? They usually don't survive, the only way this could make your speedo have a problem is if the lower bearing was completely gone and letting the shaft slide to the right, but thats reachin, otherwise no.
bluelightning
New member
haven't pulled the case out yet, was gettin late last night and i had homework to do, which should definately be my first priority at this point. looking at the shaft where the bolt head sheared off, it has shifted towards the back of the sled. i felt on the inside of the tunnel when reaching in to drain the oil out of it, and before draining, it was wet with fluid on the other side of that bearing...and it felt like there is a loose o-ring type thing. what do you mean by if the bearing spun in the case? sorry i'm kinda a weekend warrior i'm not gonna lie lol. and how to i go about removing the case itself? looks like i have to take out the 2 bolts holding the brake caliper on, and then just 2 bolts holding the case on? and how do i remove the nut holding the top gear on? it just spins the whole shaft when i turn it
you need to hold the brake on!! and pull hard on the nut, use good tools so you dont slip..
bluelightning said:
weight of the track will pull this back like you describe when the bearing has fallen apart.
bluelightning said:
The loose o-ring type thing is most likely the seal from the case. #4
bluelightning said:
When the bearing starts to get hot and break-down, it will sometimes lock up and force the outside 'race' to spin in the case, meaning steel spinning against aluminum.
bluelightning said:
Remove the top nut while holding the brake or using the e-brake. The brake rotor should come off with the chaincase, be carefull to keep track of the 'key' for the rotor. Its a good idea to rotate the jackshaft untill the keyway is pointed up, it's a little square notch you should be able to see from the airbox side of the rotor. Oh, there are three chaincase bolts, not two. I'm sure everyone here will agree that you should change all four bearings while you're in there, maybe even the one in the cover(two driveshaft and two jackshaft)
I would probably change bearings #3(2pcs), seal #4 on the bottom shaft, bearing #8 depending on how hot I thought it got with no oil or how it feels.
If you need one, look for a used chaincase on the forums.
Attachments
Yamaha Power to Satisfy
New member
When you change the bearings, remember to order the set screws as well as they do not come with the bearing. They are a seperate part number. I found out the hard way!! Just changed my jackshaft bearig a few weeks back and didn't get the set screws with the bearing. I was just like you bluelightning, a "weekend warrior" and once you get in there it's not to bad. Just print out the blueprints in case you can't remember what goes where. Plus everyone on this site is so helpful!! 
Sorry if some of you don't have all this info but we've been PM'ing back and forth. Thought I would post this public for some scrutinty.
I'm having a hard time guessing what happened first in your case. 1: Bottom bearing is coming out in pieces 2: Case still had oil in it 3: bolt was sheared off.
some clarification is needed.
1-how are the seals situated in the bearing
2-was the case full of oil according to the stick
3-are all large parts of the bolt accounted for(it's more common for the bolt to loosen off and back out to rub against the cover)
We need to know if the seal is still on the bearing on the inside of the case. If you do a search on chaincase bearings, you'll notice a wide variety of thoughts on this but here is how Yamaha builds them. The bottom bearing is capable of holding 2 rubber seals that keep contaminents out of the bearing/contain grease inside the bearing. Yamaha installs these bearings with one seal removed and the sealed side towards the oil, keeping the oil in the case but out of the bearing. Some people will reverse this so that the oil lubes the bearing as well. If someone rebuilt the case and installed the bearing open to the oil, than it's possible that the bolt shearing/loosening off contaminated the bearing causing it to fail.
I'm having a hard time guessing what happened first in your case. 1: Bottom bearing is coming out in pieces 2: Case still had oil in it 3: bolt was sheared off.
some clarification is needed.
1-how are the seals situated in the bearing
2-was the case full of oil according to the stick
3-are all large parts of the bolt accounted for(it's more common for the bolt to loosen off and back out to rub against the cover)
We need to know if the seal is still on the bearing on the inside of the case. If you do a search on chaincase bearings, you'll notice a wide variety of thoughts on this but here is how Yamaha builds them. The bottom bearing is capable of holding 2 rubber seals that keep contaminents out of the bearing/contain grease inside the bearing. Yamaha installs these bearings with one seal removed and the sealed side towards the oil, keeping the oil in the case but out of the bearing. Some people will reverse this so that the oil lubes the bearing as well. If someone rebuilt the case and installed the bearing open to the oil, than it's possible that the bolt shearing/loosening off contaminated the bearing causing it to fail.
bluelightning
New member
haha ok here we go.
only the head of the blot was sheared off, the bolt itself was still in the driveshaft, and the bottom gear was still there. i was able to twist the rest of the bolt out, after pulling the gear off. when i pulled the gear off, a ball bearing fell out along with it. the clip, #5, seems to be wedged in there sideways. the chain case was almost to the full line on the dipstick....it certainly was not empty. when i started hearing the noise on the trail, there was a red puddle in the snow underneath the sled. hard to judge how much, given the fact it was in snow. when i felt along the driveshaft on the inside of the tunnel, above the drain bolt, it felt like there was a loose o-ring or seal, and that is where the fluid was leaking out of. and your last question, all parts are accounted for. looks as if the bolt backed itself out and began rubbing against the cover, and combined with the bearing being bad causing a driveshaft wobble, caused the head to break off? does not appear as if the seal was facing the inside of the case, as i can see all the bearings that are still in the seal. thats all the questions i can answer for now, as i have class at 8 and dont have time to go rip some more apart right now, but i should tommorow. hope that clears a few things up.
only the head of the blot was sheared off, the bolt itself was still in the driveshaft, and the bottom gear was still there. i was able to twist the rest of the bolt out, after pulling the gear off. when i pulled the gear off, a ball bearing fell out along with it. the clip, #5, seems to be wedged in there sideways. the chain case was almost to the full line on the dipstick....it certainly was not empty. when i started hearing the noise on the trail, there was a red puddle in the snow underneath the sled. hard to judge how much, given the fact it was in snow. when i felt along the driveshaft on the inside of the tunnel, above the drain bolt, it felt like there was a loose o-ring or seal, and that is where the fluid was leaking out of. and your last question, all parts are accounted for. looks as if the bolt backed itself out and began rubbing against the cover, and combined with the bearing being bad causing a driveshaft wobble, caused the head to break off? does not appear as if the seal was facing the inside of the case, as i can see all the bearings that are still in the seal. thats all the questions i can answer for now, as i have class at 8 and dont have time to go rip some more apart right now, but i should tommorow. hope that clears a few things up.
bluelightning said:
This is interesting. How far out of the shaft was the rest of the bolt? Meaning, if you put the gear back on and 're-attached' the head of the bolt, would it be holding it tight or would it be backed off 1/4", 3/8", 1/2" ....? It's all really kind of a moot point, you need to change the bearing minimum and probably the seal behind it, just would be nice to know what happened first, the chicken or the egg. The snap-ring is still interesting. You'll have to make sure it didn't spin when you get it out, that's the only thing I can think of that could have popped it, and thats a bit of a stretch. Of course, it may have been installed wrong. Pics would be nice, everyone likes pics.
