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Crank seal

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I think that the crank seal in my 1994 kx125 has gone bad. I constantly foul plugs and have excessive spooge. The jetting appears to be fine; no problems with it bogging down or anything. I have checked the float height and it appears to be fine. But my plugs come out black and wet and i have spooge dripping out of the govener boot and spitting out of the exhaust.

If it is the seal do I need to split the case to replace it, this diagram makes it look like I dont need to, the seal is #92049A i believe.

http://www.bikebandit.com/houseofmotorcycles/showschematic/m3806sch53854

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How much compression?

i dont think compression has much to do with the cranks seal. a leak down test yes, but compression?

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2 stroke always start with a compression test, takes a few minutes. Surging and excesive "white" smoke have been the tattle tale on my last 2 crank seals this year. Won't ever use Bikemaster seals again either. If he says "jetting is ok" and has spooge and wet plugs I'd definately see where the compression is at.

On a single ring piston it won't take much.

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I haven't payed to close attention to the tranny fluid it did seem a little low last timed I checked but I can't be certain, i will try to py more attention to it. The compression is on the lower side, around 130 last time I checked but still within the specs in the manual. There is some white smoke when giving it gas but none while idling.

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2 stroke always start with a compression test, takes a few minutes. Surging and excesive "white" smoke have been the tattle tale on my last 2 crank seals this year. Won't ever use Bikemaster seals again either. If he says "jetting is ok" and has spooge and wet plugs I'd definately see where the compression is at.

On a single ring piston it won't take much.

while i completely agree all i was saying is that a comp test wont tell you anything about the seals. although since they can show the same symptom, testing one could rule out the other. i havnt known bike master to be the best either.

zevens if the crank seal is leaking and causing the symptoms you describe then it would be burning tranny oil, which you may or may not notice depending on how bad it is leaking and how often you change the fluid. i would do a leak down test.

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