Oil Seal Help

[Psalm31.24]

I've got an 02 YZ 250.

I determined that the right side crankcase was leaking transmission oil into the engine and cause the plug to foul (read the "deeply confused" thread in this forum for how I determined this).

I replaced the oil seal & fired up the bike and the exact same thing happened -- fired up perfectly on the first kick, then fouled the plug once it was in gear.

Here's what I did . . .
I wiggled the gear shaft and there was no play. When I installed the new plug, it was such a tight fit I had to use a mallet to pound it in. I stretched the lining of the seal in process as the seal went in at an angle (could this be enough for the seal to lose it's ability to seal?) I seated the seal so it was flush with the brim of where the seal goes.

Did I do something wrong? or Did I misdiagnose?

thanks.

 

[Gibby]

Psalm31.24.......then fouled the plug once it was in gear.

Here's what I did . . .
When I installed the new plug, it was such a tight fit I had to use a mallet to pound it in.

:yikes: Hopefully not the spark plug! :rotfl:

 

[Psalm31.24]

Gibby, thanks for catching that typo. No I didn't pound the plug, I mean to write pound the seal.

Anyone out there can help me?

 

[nickyd]

did you coat the inside of the seal with a bit of grease? how did you stretch the seal? the collar that fits in it went in crooked? did you put the seal in and then slide the collar inside? I'm not getting a visual of this.

 

[nickyd]

wait - your subject says "tranmission - oil seal"...you did replace the right hand CRANKSHAFT seal right? just making sure.

 

[Psalm31.24]

yeah it was the right side crankcase seal. I talked it over with a guy at the shop and discovered the probable problem.

When I inserted the seal, it went in cockeyed, this probably ovalized the seal, hence the leak. I found something with the right diameter to press it in perfectly straight this time. Hope it works.

 

[billtx]

I went through this also on my YZ. Make sure you don't go to far in on the seal or it blocks the oil hole for the crank bearing. Also, you may have a collar that goes between the crank and the seal. That may need to be replaced also if it is grooved.

 

[nickyd]

isn't there a collar on that seal? that's why I was curious that you said it may have ovalized during installation - the inside lip is what you have to be more careful of. if there is a collar put the seal in and then the collar - a little grease on the inner lip of the seal will help too.