S3 Race Custom Modified EC250 Complete Rebuild
- Thread starter Jakobi
- Start date
GMP
Active member
What do you mean by "sealed bearings seemed to pass 2 stroke oil through them"? That sounds very odd to me. Sealed should be sealed. Honestly I never had one of these in my hand, what is the seal material? How hot did you get the bearing in the repeated case warmings?
I'm not a fan of these, they were born from preliminary research in DI and low oil mix ratios (emmissions). My '12 is supposed to have them as well. Funny though, since new my ignition side has the extra radial play that is indicative of the NJ roller bearing, feels like my '07. So, it was either not built to current spec and does use the open roller(fine with me) or is on the verge of going boom. Since it runs well with no excessive noise I suspect the former is true. '12s are a grab bag of leftover parts.
I'm not a fan of these, they were born from preliminary research in DI and low oil mix ratios (emmissions). My '12 is supposed to have them as well. Funny though, since new my ignition side has the extra radial play that is indicative of the NJ roller bearing, feels like my '07. So, it was either not built to current spec and does use the open roller(fine with me) or is on the verge of going boom. Since it runs well with no excessive noise I suspect the former is true. '12s are a grab bag of leftover parts.
Jakobi
Super Moderator
Well I assume the oil passed through. The mains are SKF 2RS. Rubber seal both side. Maybe the oil wasn't, but when using a small syringe and pushing some oil down through the case holes it flowed out both sides of the bearing space.
One of the bearings had a short stint in the oven at 100C which is a bit hotter than the bearings should be, and I was worried that it might have cooked the grease out but it appears to be ok. After that I made sure the mains were the last bearing to be put in the cases. They were one of the easier ones to drop in anyway. Of course this was the first bearing I attempted to drop in and sat sideways. I had to use the heat to get it to fall back out. No way I could pull it out by hand without it and no way I was going to force it in.
After the whole lot was done and cooled down and lubed, I used an awl and picked the inner lip up a bit just to check that there was still grease in there. All is well. I guess the seal might be enough to hold grease in, but not enough to stop oil entering. I guess the same way that water still manages to make its way into sealed bearings in wheels etc.
I know you're not a fan of these Glenn, and I'm not really either, but for me being my first time in here, and not knowing the front from the back it was just easier to purchase a complete bearing kit. One less thing to worry about. I also managed to get 260hrs out of these without any issue, so I consider that to be a postive thing. They've always had a little radial play as well when grabbing the flywheel. Not much, but a bit. It freaked me out after my last top end 110hrs ago. It hasn't got any worse and apparently the C3 bearings will have a little radial play to them as well.
One of the bearings had a short stint in the oven at 100C which is a bit hotter than the bearings should be, and I was worried that it might have cooked the grease out but it appears to be ok. After that I made sure the mains were the last bearing to be put in the cases. They were one of the easier ones to drop in anyway. Of course this was the first bearing I attempted to drop in and sat sideways. I had to use the heat to get it to fall back out. No way I could pull it out by hand without it and no way I was going to force it in.
After the whole lot was done and cooled down and lubed, I used an awl and picked the inner lip up a bit just to check that there was still grease in there. All is well. I guess the seal might be enough to hold grease in, but not enough to stop oil entering. I guess the same way that water still manages to make its way into sealed bearings in wheels etc.
I know you're not a fan of these Glenn, and I'm not really either, but for me being my first time in here, and not knowing the front from the back it was just easier to purchase a complete bearing kit. One less thing to worry about. I also managed to get 260hrs out of these without any issue, so I consider that to be a postive thing. They've always had a little radial play as well when grabbing the flywheel. Not much, but a bit. It freaked me out after my last top end 110hrs ago. It hasn't got any worse and apparently the C3 bearings will have a little radial play to them as well.
GMP
Active member
In most cases they have been fine. The few reported failures I have read about have been due to seal failure, and subsequent loss of grease due to being spun out by centrifugal force. An open main bearing is lubricated by separated oil dripping through the hole in the transfer port area of the cases. The presence of the seal, even if it is compromised, limits this.
Hope it works out. IMO, its just one more thing to fail that is not needed in a racing engine. My local supplier does a lot of hybrid ceramics, thats what I'll likely put in mine when its time.
Next time, use dry ice to freeze the bearings, they will drop in a lot easier. Your freezer does not give you a high enough temp differential for an easy shrink fit. If by chance you can get LN2, its a snap.
Hope it works out. IMO, its just one more thing to fail that is not needed in a racing engine. My local supplier does a lot of hybrid ceramics, thats what I'll likely put in mine when its time.
Next time, use dry ice to freeze the bearings, they will drop in a lot easier. Your freezer does not give you a high enough temp differential for an easy shrink fit. If by chance you can get LN2, its a snap.
Jakobi
Super Moderator
So I picked the seals out of the mains I pulled out, and there's no grease left in them at all. Do you think it would be wise of me to remove the inward facing seals? I can't get the outer ones unless if I pull the bearings out again.
Thoughts? Will I get enough splash lub from the crank side to keep them happy? Does this increase the risk of shagging my main bearings if my bike goes for a swim and takes on a heap of water?
Thoughts? Will I get enough splash lub from the crank side to keep them happy? Does this increase the risk of shagging my main bearings if my bike goes for a swim and takes on a heap of water?
GMP
Active member
Like I said, the bearings are lubed by the separated oil running down the holes in the cases. There it is trapped and picked up and slung through the bearings. Bad idea pulling inside seal off. Either commit to use as is or get rid of them and run open bearings.
No grease in old bearings should tell you something, shouldn't it?
No grease in old bearings should tell you something, shouldn't it?
When i rebuild mine, i take of both seals from main bearings. Clutchside bearing was with seal from factory
And fail badly...even broke a case. It going now 200hrs without any seals in main bearings and no freeplay when crab flywheel or clutchside either
Someone say it have to take both seals of, it makes sense because then bearing can breathe oil,gas air mixture all time.
Sorry my english...not perfect... I am finish
I think if seal fail grease go out but oil,gas,air mixture cant lubed it well because seals..even broken ones
I can post later today couple pics of cracked case and fail clutch side main...It was used bike so cant say hom much hrs but i guess not more than 200...it was 2 years old 2009 bike when i rebuild it.
Sent from Razr MAXX
Jakobi
Super Moderator
When i rebuild mine, i take of both seals from main bearings. Clutchside bearing was with seal from factory
And fail badly...even broke a case. It going now 200hrs without any seals in main bearings and no freeplay when crab flywheel or clutchside either
Someone say it have to take both seals of, it makes sense because then bearing can breathe oil,gas air mixture all time.
Sorry my english...not perfect... I am finish
Sent from Razr MAXX
It makes sense. Just kicking myself for not doing it sooner. Hopefully I'll be able to use a torch arond the mains and have them drop out without too much fuss.. otherwise.. back in the oven and probably have to do most of them again. You live and you learn. Better now than later.
GMP
Active member
Maybe not perfectly good English but perfectly good advice.
Jake, where your at now means that you cannot remove the bearings and reuse them without seals. Once you press a bearing out with force across the inner/outer races, its junk.
Just go get some new high quality open bearings from a supplier. You will pay less and get a better, proper part. Put it together right and not worry about it.
If mine lasts through this year, I'll pull it down and do the same. If it goes bang I'll just swap my trusty '07 engine in.
Jake, where your at now means that you cannot remove the bearings and reuse them without seals. Once you press a bearing out with force across the inner/outer races, its junk.
Just go get some new high quality open bearings from a supplier. You will pay less and get a better, proper part. Put it together right and not worry about it.
If mine lasts through this year, I'll pull it down and do the same. If it goes bang I'll just swap my trusty '07 engine in.
I don't know how tight the outboard face of the main bearing is to the case, but here's a thought.
Since you picked out the inboard seal, is it possible to get a small tool past the ball spacer and push the outer seal off the bearing? If there is a bit of room outboard of the main bearing, the seal could drop enough to be pulled out the bearing bore. Distorting the seal is no big deal since you are discarding it anyway.
Since you picked out the inboard seal, is it possible to get a small tool past the ball spacer and push the outer seal off the bearing? If there is a bit of room outboard of the main bearing, the seal could drop enough to be pulled out the bearing bore. Distorting the seal is no big deal since you are discarding it anyway.
GMP
Active member
That will not work, the bearing is pressed in tight to the cases. Two new bearings are cheap compared to the damage from a failed one, and all the time involved.
What pisses me off about this is there is absolutely no reason for it. Everyone knows what works and has worked for years. They simply introduced another possible failure mode with no positive returns. Component life tests should be limited to engineering prototypes in the factory, not in production machines. Whoever signed off on that change wouldn't last long in places I've worked, thats for sure.
What pisses me off about this is there is absolutely no reason for it. Everyone knows what works and has worked for years. They simply introduced another possible failure mode with no positive returns. Component life tests should be limited to engineering prototypes in the factory, not in production machines. Whoever signed off on that change wouldn't last long in places I've worked, thats for sure.
Jakobi
Super Moderator
Maybe not perfectly good English but perfectly good advice.
Jake, where your at now means that you cannot remove the bearings and reuse them without seals. Once you press a bearing out with force across the inner/outer races, its junk.
Just go get some new high quality open bearings from a supplier. You will pay less and get a better, proper part. Put it together right and not worry about it.
If mine lasts through this year, I'll pull it down and do the same. If it goes bang I'll just swap my trusty '07 engine in.
I didn't have to press on either of the races with the mains. With enough heat and cold bearings they dropped in by hand. I just reversed the proceedure and used the torch around the bearing. Flipped the case over and gave it a few whacks against a folded up towl and the came back out.
I picked the seals off. The flywheel side one is a little different than whats expected. Jilkoo. When you put them in without seals which way did you face this one? Note - its also a C4 rated bearing.
I didn't have to press on either of the races with the mains. With enough heat and cold bearings they dropped in by hand. I just reversed the proceedure and used the torch around the bearing. Flipped the case over and gave it a few whacks against a folded up towl and the came back out.
I picked the seals off. The flywheel side one is a little different than whats expected. Jilkoo. When you put them in without seals which way did you face this one? Note - its also a C4 rated bearing.
I cant remember i put just same way than older one's were in cracked case. I am not expert but i guess doesnt matter which way...i just put same way than factory was put them, because havent find that great forum yet..to ask someone
Sent from Razr MAXX
Jakobi
Super Moderator
I cant remember i put just same way than older one's were in cracked case. I am not expert but i guess doesnt matter which way...i just put same way than factory was put them, because havent find that great forum yet..to ask someone
Sent from Razr MAXX
Thanks. They were installed as per the top pic facing inwards towards the crank. I'm not sure about the flywheel side bearing at all. Looking at it it appears to use a plastic cage for the bearings and I'm not sure it would really allow as much splash lubing from the back side as it would from the front. I'm also sus about plastic?? Research kind of confirms that its likely a Plastic Retainer/Caged bearing too.
I see this turning into wasted $$ now. If I was to replace that one bearing, can I just get another quality ribbon caged bearing same as the other side, in the right size. Is it worth the $$ to drop both in with pricey ceramic jobbies? I think I'll put the whole thing on hold and go see someone in the bearing store when I pick up the crank on Wednesday.
Jakobi
Super Moderator
I've done some research and I'm going to use the bearings I have without the seals. As stated above, neither of these bearings have been pressed in or out. The just dropped in with heated cases, and came out with heat and smacking the case against some rags. The fit when back to temp was good and no chance of pulling them out.
The flywheel side bearing is an SKF Explorer series with Polyamide 6,6 cage.
From SKFs website: Solid polymer cages are characterized by a favourable combination of strength and elasticity. The good sliding properties of the polymer on lubricated steel surfaces and the smoothness of the cage surfaces in contact with the rolling elements produce just little friction so that heat generation and wear in the bearing are at a minimum. The low density of the material means that the inertia of the cage is small. The excellent running properties of polymer cages under lubricant starvation conditions permit continued operation of the bearing for some time without risk of seizure and secondary damage.
http://www.skf.com/group/products/b...or-rolling-bearings/cage-materials/index.html
http://www.skf.com/binary/12-36038/6270-EN.pdf
From that it sounds like it will be up to the job. Back on target after dealing with a mega mind bong.
The flywheel side bearing is an SKF Explorer series with Polyamide 6,6 cage.
From SKFs website: Solid polymer cages are characterized by a favourable combination of strength and elasticity. The good sliding properties of the polymer on lubricated steel surfaces and the smoothness of the cage surfaces in contact with the rolling elements produce just little friction so that heat generation and wear in the bearing are at a minimum. The low density of the material means that the inertia of the cage is small. The excellent running properties of polymer cages under lubricant starvation conditions permit continued operation of the bearing for some time without risk of seizure and secondary damage.
http://www.skf.com/group/products/b...or-rolling-bearings/cage-materials/index.html
http://www.skf.com/binary/12-36038/6270-EN.pdf
From that it sounds like it will be up to the job. Back on target after dealing with a mega mind bong.
