performance symptoms of a leaky crank seal?

ian van opijnen /

hello all!

e50 maxi

kstar 70cc piston port

20mm phbg

biturbo

over the past few weeks ive noticed an increase in oil mix coming out from my front sprocket area, today while changing sprockets i noticed that it looks like the seal's outer layer was completely gone, (or so it looked) i could see the little metal spring that wraps around the shaft on the inside of the seal. is that how its supposed to be? ive never looked before!

what would be the performance symptoms of a leaky seal? my bike does not like high rpms and almost makes no power higher in the rev range, low and mid power is excellent though.

worth it to get a new crank while im splitting the case?

Re: performance symptoms of a leaky crank seal?

Darrell Gabbard /

if the output shaft seal is starting to go then its a good indication to replace them all. If you get a new crank then you wont be waiting for a replacement when you do the tear down or any replacement part for that matter

Re: performance symptoms of a leaky crank seal?

Downhill Harvey (OFMC) /

That seal will have no effect on how it will run. The crank seals are different, when you see an oily/dirty mess behind the flywheel, they're bad. If it's all clean, then they're good.

Re: performance symptoms of a leaky crank seal?

ian van opijnen /

Ah yes, no residue on the inside of the flywheel and no smoke from tranny fluid getting in so I'd assume that's fine... I read somewhere that they can sometimes hold Pressure but not vaccume, or vise versa and figured maybe that's why I've been hitting an rpm wall since I've owned the bike( unless it's on a stand). And yeah I was looking at the output shaft seal. It leaks ... A lot. So with no crank seal leak, but a very leaky shaft seal.... Just go ahead and replace all? Or wait till somthing bad happens hah

Re: performance symptoms of a leaky crank seal?

don't run out of trans oil. that is how your right side crank bearing is lubed.

Re: performance symptoms of a leaky crank seal?

you can probably replace that output shaft seal without

taking the engine apart.

use a wood screw to pull it out

tap new seal in with a big socket and rubber mallet

what carb you running?

what pipe you running?

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