2004 crf 250r How to test the Center Case Gasket

While I enjoy spending time with my son working on his dirtbike I think it should run for more then  day before we need to fix it again.  He had an oil migration problem trans to engine.  We replaced both the crank and the balance seal.  It wouldn't start after we got the engine timed.  checked the valves rechecked the timing and finally did a leak down test.  Didn't hold worth a darn.  Took it apart and looked it over and put a new head gasket in and it started first time.  So he's off on his trip with his buddies and texts me saying the bike is running great.  Better then ever "Thanks Dad!"  Next day he tells me the oil migrated again.  As far as I can tell there are only two possible problems the crankcase seal or the center gasket.  Ordered a new seal.  This time I went with the '06 and going to install it when he gets back but wondering if there is a test for the center case gasket.  I can't find an oil flow diagram in the Clymer manual but that would be helpful.  Is there one available anywhere?  

 

I can't see how a leakdown test would tell me if the crankcase center gasket was broken but I guess that is a possibility.  

 

Any ideas or help would be appreciated

I had an oil migration issue with mine when I bought it, 04 250f. The oil was going from the engine to the trans because the vent hose was pinched completely off. You should change the balancer seal and probably bearings too assuming its going the same way. The good news is you dont have to split the cases to fix it and the gasket between the two has nothing to do with it.

 

Let us know which way the oil is migrating and someone will be able to give you more details on what you need to change and what may be causing it. That is what worked for me but if its going from engine to trans I beleive it a different seal, I could be wrong though.

I have posted in this forum my fix for tranny to engine oil migration but I'll recap

 

I have an 05 and use the clymer manual for 02 to 05. IMO make sure you are getting the correct OEM parts for the 04 AND the correct VIN # of your bike. I use RMATV to get my OEM part #'s and their OEM mirco fiche for both left/right/water pump/balancer to help dis-assembly/re-assembly. there is no specific topic in the clymer and you need to look at multiple chapters for the fix

 

IMO - If your still getting tranny to engine side, this will be the right side outer crank seal or left side balancer seal. You need to pull both outer cases.

 

I'm going from memory so......

 

Drain engine and tranny oil and pull both outer covers

 

Do the right side first...

New Outer case gasket.

Do the water pump seals and bearings while the outer case is off.

Right side crank seal is a different OEM # then the left. make sure you put the seal in the correct way.

Make sure you follow the manual for removing/re-installing the clutch, kick start, aligning gears, water pump, etc correctly.

Check clutch components for wear

 

Left side..

new outer case gasket

Clean oil screen.

Replace balancer seals and bearings.

Replace relief valve.

You need to remove the cam chain to do the left side outer crank seal. I did not do this.

 

When I did mine the first time i only did the right side outer crank seal. Left the engine oil drain bolt out and as soon as I put in tranny fluid, it poured out of the engine oil drain bolt. Had to pull the right side outer case, then left side outer case and did the balancer seal.

 

The parts were about $200 and not that hard if you have the right tools, are some what mechanically inclined read through the sections in the clymer.

 

I might have a list of the oem part numbers I ordered if you want them but double check againest the 04

I have posted in this forum my fix for tranny to engine oil migration but I'll recap

I have an 05 and use the clymer manual for 02 to 05. IMO make sure you are getting the correct OEM parts for the 04 AND the correct VIN # of your bike. I use RMATV to get my OEM part #'s and their OEM mirco fiche for both left/right/water pump/balancer to help dis-assembly/re-assembly. there is no specific topic in the clymer and you need to look at multiple chapters for the fix

IMO - If your still getting tranny to engine side, this will be the right side outer crank seal or left side balancer seal. You need to pull both outer cases.

I'm going from memory so......

Drain engine and tranny oil and pull both outer covers

Do the right side first...

New Outer case gasket.

Do the water pump seals and bearings while the outer case is off.

Right side crank seal is a different OEM # then the left. make sure you put the seal in the correct way.

Make sure you follow the manual for removing/re-installing the clutch, kick start, aligning gears, water pump, etc correctly.

Check clutch components for wear

Left side..

new outer case gasket

Clean oil screen.

Replace balancer seals and bearings.

Replace relief valve.

You need to remove the cam chain to do the left side outer crank seal. I did not do this.

When I did mine the first time i only did the right side outer crank seal. Left the engine oil drain bolt out and as soon as I put in tranny fluid, it poured out of the engine oil drain bolt. Had to pull the right side outer case, then left side outer case and did the balancer seal.

The parts were about $200 and not that hard if you have the right tools, are some what mechanically inclined read through the sections in the clymer.

I might have a list of the oem part numbers I ordered if you want them but double check againest the 04

so you can replace both crank seals without splitting the bottom end??

so you can replace both crank seals without splitting the bottom end??

Correct.  Ive replaced both seals on my 2005.  Its pretty simple, you will need to take the cam chain and flywheel off though but that's not a hard task.  Can do them all with the motor still installed in the bike

Correct. Ive replaced both seals on my 2005. Its pretty simple, you will need to take the cam chain and flywheel off though but that's not a hard task. Can do them all with the motor still installed in the bike

Thank you

I already have my flywheel off I just need to remove the cam chain

Thanks for the reply

At 210 hours

My hotrod crank seal on the left has popped out on angle and is rubbing on my camchain. .. you can see all silver where it is been rubbing :(

Hopefully the bearing didn't cause it but I guess I'll find out when I remove the camchain tensioner and see if I have any movement. .. the bike still rode good it just had some noise and metal shavings (magnetic )

so you can replace both crank seals without splitting the bottom end??

You got the correct reply. I did not do the left side crank seal on my bike cus I didn't want to have to deal with removing the cam chanin.

 

I'm since put the list of 2005 CRF250R OEM parts numbers for this (with out the left side crank seal and its is a different part number and size than the right side crank seal) in Excel if this helps anyone.

 

Clipboard01_zpslhkzcxdc.jpg

You got the correct reply. I did not do the left side crank seal on my bike cus I didn't want to have to deal with removing the cam chanin.

I'm since put the list of 2005 CRF250R OEM parts numbers for this (with out the left side crank seal and its is a different part number and size than the right side crank seal) in Excel if this helps anyone.

Clipboard01_zpslhkzcxdc.jpg

mine is a 450x so part numbers are different but it sure will help a lot of others

Create an account or sign in to comment

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

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now