So I thought I had a crank seal leak??

bbeers

New Member
Feb 21, 2008
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I replaced the crank seal on the flywheel side because I thought I had a oil leak there. I didn't completely put it back together and when I went out tonight it looks like there was a little bit of oil sitting in the bottom of the case. I'm thinking where can this be coming from? I took the two stator screws loose and removed the stator and it looks like the oil is coming from around the bottom screw of where the stator mounts. Is this common?
 
i dont quite understand were you think its coming in from but most likely if its not coming through the crank seal(asuming you installed it corectly) then you have a bad seal between the 2 case halfs and its coming in through there. worst case senario would be a crack/hole down there but its probably just the seal between the 2 case halfs. that would require splitting the cases, cleaning the seals up nicely and while your in there, replace bearings, especialy main bearings(crank) depending on hours from the last rebuild.
 
If you think that you might have a air like on the flywheel side then remove the cover. Start the engine and use carb clean to spray around the seal; if you have a leak then the engine will rev up; like having the choke on
If you have questions PM me; I know most of the people on here are young and I went through all the same things. I started working on engines when I was 8 and now I am 34. Just keep working through the problems and you will learn. I learned from my mistakes more from anything.
Good luck
 
This is where the oil is coming from. The bottom hole that the stator mounts to.

30j5p1v.jpg
 
weird place to get an oil leak. can you tell if it's mix or oil?
stand the bike up on it's grab bar and see if you can see any visible damage to the underside of the motor.
really the best thing to do is to split the cases so you can see if there's some kinda damage in the crank area, but if you just want a bandaid, just wrap some teflon tape around the bolt (clockwise so it won't unwind when you intall the bolt) to seal it and ride!
make sure to keep an eye on it.
 
that there is premix!!! that screw holds the crank case part of the engine together and on a 2stroke the fuel mixture is sucked throught the crank housing before its forced into the cylinder. 89 custom is correct, the seal between case halves is leaking. you can either A-put some silicon on the screw and put it back in and hope it srops or B- split the cases and slap so new yamabond on the case halfs. doesnt seem like it would affect performance much, because the halfs should almost seal by themselves.maybe u smashed the front of the case on something?
 
remember to keep any eye on it......if it keeps leaking, you might start suckin dirt and crap into your chamber. then you'll have no choice but to split the cases.