WR400 Oil Leak

i have been having a little trouble with my wr400f and was hoping someone could help.

The oil seal behind the front sprocket was leaking oil. I replaced the seal and it was still leaking, and when the bike comes off tick over it seems to pump the oil out. i then checked all the breathers and put another seal, O-ring and spacer behind the front sprocket. This still did not cure the problem. I then put a new piston and rings in, i also had the barrel re-plated because the old one was worn. i then put in another new oil seal and this has not helped in any way the oil is still coming out. I have also checked the oil level and it is ok and all the oil lines and filters are clear.

Please Please Please Help

enus

How do you know that there is oil coming out of the seal? Some bikes have the breather hose for the cylinder head routed down and around the frame and it points close to the front sprocket. It always leaves a dribble on the floor after riding.

If this is not the case, then I would assume that something could be wrong with the shaft causing the seal to work improperly. How tight are you running your chain?

Hope this helps.

Hi thanks for the quick response. The chain is quite slack and the oil is definitely coming from the seal. The last time i put a seal in i started the bike with the front sprocket off and you could see the oil weeping out from between the shaft and the seal. and when you rev the bike it seems to pump the oil out.

I have no idea what could cause this and would appreciate any suggestions on what the fault could be.

What kind of shape is the sleeve in? Does it have a groove worn in it? If so replace the sleeve. Could you be damaging the new seal when installing it? Do you grease the new seal ID and the sleeve at install? Also check the shaft bearing. If it has excesive play that may be a problem.

After the first seal i put in was leaking I then replaced the o-ring, sleeve and i put another new oil seal in. i also have checked she shaft for play and there was not any. This did not fix the problem. i was then told it might be crankcase pressure due to worn piston, rings and sleeve these were all replaced along with another oil seal and it still leaks. I have no idea of what can be causing the oil to leak out and am extremely grateful for any advice.

Do you have it apart? I think some pictures will help in figuring this one out.

Are you sure you have the seal in the correct way? All the way seated?

Verify your installation process with the manual, and look at some on line micro fisches for diagrams.

What does the seal look like when you take it out? Are you putting a little grease on the inner lip where the shaft goes through?

Keep us posted

After the first seal i put in was leaking I then replaced the o-ring, sleeve and i put another new oil seal in. i also have checked she shaft for play and there was not any. This did not fix the problem. i was then told it might be crankcase pressure due to worn piston, rings and sleeve these were all replaced along with another oil seal and it still leaks. I have no idea of what can be causing the oil to leak out and am extremely grateful for any advice.

There should not be any crankcase pressure even with worn rings. The motor basically is open vented via the breather hose unless perhaps the hose is blocked?

Thank you for the response but unfortunately i have checked all these things already. I have checked the shaft for play and there is no movement. i have also checked to see if it is straight and it is. on the original seal i removed there was a little wear but on the second seal i fitted there was no apparent sign of wear but it had only been in for 5 minuets and now i am on the third seal. when they are fitted they are always greased and seated correctly. I have also checked the oil ways and the oil way from the shaft returns directly to the sump and is also clear.

Unfortunately i cannot post any pictures at the moment but i don't think they would help much as everything looks fine.

I really appreciate the help you are giving me and i hope someone out there has heard of a fault like this and has a solution.

You are checking the oil when the bike is warm right?

Double check your part numbers and also look at the part numbers for different years of bikes to see if they change. Was there / did you replace the bearing on the shaft by chance? Could it be that you installed the bearing backwards?

I would look up some info on line for you, but I am stuck here in dial up land until work in the morning.

Later

Given everything that you've done or looked at is the case maybe cracked? Ever thrown a chain or anything like that?

Thanks for all the replies. I do check the seal when the bike has had time to warm up. But I have no idea if the bearing is in the right way round as i Have not fitted it. The crank case is in great condition and no sign of a thrown chain. I would appreciate some more suggestions as i have no idea what can be causing this oil leak

picture time!!!

hi unfortunately i don't have a digital camera so i will have to see if i can borrow one from a mate. I can not see how a photo will help as everything looks fine apart from the oil coming out. I heard from a friend that the oil pressure could be to high and that is pushing the oil out is this possible?

when i can get a camera what sort of picture would help?

Thanks for all your Help

Pictures will let those with more experience help you figure out what your problem is. Maybe you are missing something and don't know it? I am at a loss though.

The oil pressure is only used to get the oil to the parts that need it, the transmission and bottem sump area are not presurrised.

One thought might be that if the bearing for the shaft was taken out, it might not be ligning up correctly with the oil hole in the shaft. Or seals might not be correct.

There is supposed to be a washer behind the bearing, then the bearing, then the seal, then the seal retainer. Just trying to clarify.

Hi thanks a lot for you help. I have another seal on order an plan to fit it when it arrives. What pictures do yo think would help? I was going to send one of the old seal in place and then one with it removed ready for the new one. will this be OK?

The bike is a wr400f 2000 model do you know what the part number should be for the oil seal so i can compare it with the number on the new seal when it arrives.

Also is there any way of checking that the bearing is in correctly with it in place or would i have to take it all apart?

Thank you very much for all your help this fault has me totally confused

27 O-RING (5GS5)

93210-22298-00

24 BEARING (5GS5)

93306-20593-00

25 OIL SEAL (5GS5)

93102-32480-00

Take a look here

http://images.powersportsnetwork.com/fiche/images/Yamaha/2000/Motorcycles/957_transmission.gif

Pictures:

Old seal in place, shaft with no seal, old seal side by side with new seal (front & back & side)

As for the bearing, I am not sure how it goes in, I guess I would assume it can only be removed when splitting the cases and removing the shaft.

Have you noticed anything strange when changing the oil filter?

Sorry I can't be more helpful. I am not sure as to what would be the cause. Another thing to consider is to look around your area for others that ride and see if they can help, maybe see a dealer?

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