Jump to content

Crank Bearing And Seal

Recommended Posts

Hey guys. 

I seem to be having a problem with my wet side crank seal leaking. I get a really bad smell from my exhaust and keep getting ash build up on my spark plug. 

So I pulled the right side cover off and found out that the bearing got some play in it (left side is still good). When I wiggle it around I get some air bubbles where the seal meet the crank shaft so I think that's where it leaks.

I am having a race in 10 days and won't have time to split cases before that. Do you think I can just put a new seal in and it will hold tight for atleast a couple of hours or will it also leak you think? 

Share this post


Link to post
Share on other sites
2 minutes ago, P84ONE said:

Never know. I would pull rebuild. Could do it in three days once you have all the parts. 

My local shop quoted me 5hours of work so I am sure I can do it in about 10. But I was planing full rebuild with crank bearing, rod, trans bearing after this race and really sucks to have to split it twice in the same year :banghead:

 

Share this post


Link to post
Share on other sites
4 minutes ago, Christoffer Brandel said:

My local shop quoted me 5hours of work so I am sure I can do it in about 10. But I was planing full rebuild with crank bearing, rod, trans bearing after this race and really sucks to have to split it twice in the same year :banghead:

 

Then you need to make the assessment. "IS" the bearing so bad that it "could" last a couple hours of racing? 

I'm not you, engine is not in front of me, so you'll have to be the best judge.

Why twice? Just rebuild it completely now, and be done for a while.

Sorry man, good luck on what you decide. 

Share this post


Link to post
Share on other sites

I would feel  slightly more comfortable replacing that seal for one race( still somewhat nervous)  if after seal replacement you have the pressure test tools to pressure test the top and bottom engine. if it leaks you know it will not last an hour.

if the crank is flopping around you need an new motor anyway you just need to decide if you want to risk a case and a cylinder for one race?

  • Like 1

Share this post


Link to post
Share on other sites
14 minutes ago, P84ONE said:

Then you need to make the assessment. "IS" the bearing so bad that it "could" last a couple hours of racing? 

I'm not you, engine is not in front of me, so you'll have to be the best judge.

Why twice? Just rebuild it completely now, and be done for a while.

Sorry man, good luck on what you decide. 

I am not so afraid the bearing will go out on me. It got some play but it's not horribe and it's an enduro race so not alot of WOT. 

I know you right about the rebuild. Problem is I have to buy the parts before I split it or it won't arrive in time. And I can bet my rats ass that I'll have to change a gear or shiftfork to. But I don't know before I split her.

Guess I just came here wondering if a new seal would hold the oil for 2-3 hours or if they go bad right away if there is some play. 

Share this post


Link to post
Share on other sites
5 minutes ago, Christoffer Brandel said:

I am not so afraid the bearing will go out on me. It got some play but it's not horribe and it's an enduro race so not alot of WOT. 

I know you right about the rebuild. Problem is I have to buy the parts before I split it or it won't arrive in time. And I can bet my rats ass that I'll have to change a gear or shiftfork to. But I don't know before I split her.

Guess I just came here wondering if a new seal would hold the oil for 2-3 hours or if they go bad right away if there is some play. 

If the play only deforms the "lip" of the seal than you should be good for a moto. If it deforms past and gets to the spring tension inside the ring, FORGETIT!!!

  • Like 2

Share this post


Link to post
Share on other sites
1 hour ago, Christoffer Brandel said:

My local shop quoted me 5hours of work so I am sure I can do it in about 10. But I was planing full rebuild with crank bearing, rod, trans bearing after this race and really sucks to have to split it twice in the same year :banghead:

 

I'd do it in 4 :thumbsup: engine back in running :ride: that's if swingarm bolt come out easily lol

  • Like 3

Share this post


Link to post
Share on other sites
1 hour ago, GCannon said:

I would feel  slightly more comfortable replacing that seal for one race( still somewhat nervous)  if after seal replacement you have the pressure test tools to pressure test the top and bottom engine. if it leaks you know it will not last an hour.

if the crank is flopping around you need an new motor anyway you just need to decide if you want to risk a case and a cylinder for one race?

I actually bought a pressure tester before I took it apart, unfortunely the shipping is 3-4 weeks so won't arrive in time. Good tool to have in the future though. 

I know I'll have to replace it and it was my plan all along, felt left side when I did topend like 10 hours ago and it had zero play so just assumed right side was g2g, but apparently not. I'd guess wet side get more stress though since it has the primary drive. 

You make a good point though, will have to think this over.

53 minutes ago, P84ONE said:

If the play only deforms the "lip" of the seal than you should be good for a moto. If it deforms past and gets to the spring tension inside the ring, FORGETIT!!!

Thank you, just the answer I was looking for :thumbsup:. I'll re-evaluate tomorrow and try to post a short movie to get a 2nd opinion for you guys. 

Share this post


Link to post
Share on other sites
30 minutes ago, Motox367 said:

I'd do it in 4 :thumbsup: engine back in running :ride: that's if swingarm bolt come out easily lol

If you lived in Sweden I'd let you do it :thumbsup:

Edited by Christoffer Brandel
  • Like 1

Share this post


Link to post
Share on other sites
9 minutes ago, Christoffer Brandel said:

If you lived in Sweden I'd let you do it :thumbsup:

Lol dam... No I will say 4 hours with engine in bike could do and have but that just gets inside cleaned and put back together and correctly.  But better to not be rushed and clean outside of engine up give her some love. That's how I prefer them acutely engine only. But have done in pinch qiuck night before many times. Practice breaks them in :ride: it might be ok, it might not . that's your call. I'd definitely try to baby the engine but also don't lugg to bad

Edited by Motox367
  • Like 2

Share this post


Link to post
Share on other sites
7 minutes ago, Motox367 said:

Lol dam... No I will say 4 hours with engine in bike could do and have but that just gets inside cleaned and put back together and correctly.  But better to not be rushed and clean outside of engine up give her some love. That's how I prefer them acutely engine only. But have done in pinch qiuck night before many times. Practice breaks them in :ride: it might be ok, it might not . that's your call. I'd definitely try to baby the engine but also don't lugg to bad

Thats some speed! 

  • Like 2

Share this post


Link to post
Share on other sites
13 minutes ago, P84ONE said:

Thats some speed! 

Was tought but the best in my eyes.  And how to ride by a amazing man :thumbsup:

  • Like 1

Share this post


Link to post
Share on other sites
1 minute ago, Motox367 said:

Was tought but the best in my eyes.  And how to ride by a amazing man :thumbsup:

Do you call him Dad, Sir, Honor, King, or your excellence?

Edited by P84ONE

Share this post


Link to post
Share on other sites
10 minutes ago, P84ONE said:

Do you call him Dad, Sir, Honor, King, or your excellence?

No lol just a good buddy I met in my late teens racing.  Took me under his wing want racing every weekend all over for many many years.  He actually finished top 20 this year at Lorettas and hasn't been racing much this year . I was rough on 125s  Lol we did alot of engines and couple pro kids 65-125s . I just kept doing them as I do many more than him now but his ways I still use. still great freinds to this day

  • Like 2

Share this post


Link to post
Share on other sites

I am going to say you might get one moto, and you might not. That is .5-1.25mm of play and it could grenade during your moto, locking up the engine, throwing you into bodily pain. 

Sorry man, I caution on safety. 

Share this post


Link to post
Share on other sites
1 hour ago, P84ONE said:

I am going to say you might get one moto, and you might not. That is .5-1.25mm of play and it could grenade during your moto, locking up the engine, throwing you into bodily pain. 

Sorry man, I caution on safety. 

I'll have to agree with you. Going for the full rebuild. 

Thank you all for the inputs :thumbsup:

Share this post


Link to post
Share on other sites

I would go all OEM on bearings within the case. They are KOYO Japan and you can't get better quality. 

Seals, three seals have a shaft spinning constantly as the engine is running, OEM again is my prefered seal on these three. I have heard that ProX comes out of the same factory, but prefer OEM. 

All the other seals are there to keep the oil in and the shaft in them only moves back and forth. So, those particular seals can be SKF, ProX, or equal. Would not use anything with AllBalls on it. 

My .02, other opininons may very. 

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×