CG125 persistent oil leak

[scotto75]

Hi all.

I have a CG125 Brazil model (‘88) that is leaking oil from the left side. It doesn’t have a centre stand, so after every trip a little oil leaks out. It looks like it comes from the crankshaft oil seal. I have replaced the oil seal and o-ring twice but it still comes back. I have used cheapo oil seals off eBay, as CMSNL doesn’t stock any NOS ones anyway. The last time I changed it was a month ago and it is now leaking quite a bit again.

I would like to know if it is possible to use a sealant when installing the seal?

How can I tell if it’s the crankshaft out of alignment that’s causing the issue?

Could it be something else i’m Missing?

Any help would be great thanks!

[Chris45]

Brazil built CG's were utter trash m8. Build quality was exceptionally poor, even by Jap standards. If you've replaced the seal the case is probably distorted. Get rid asap.
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Honda CG125>Suzuki GT185>Honda CB 250N>Suzuki GSX400>Honda CX500B>Kawasaki GPZ305> Kawasaki GPZ550>Kawasaki GPZ500S+BMW 650GS

[neptune8]

It is possible that the crankshaft bearing is worn. Try moving the crankshaft end within the bearing. Having said that, a worn bearing would probably make a rumbling noise, so you would know. Local bearing specialists often stock quality seals, but take the old seal along as a pattern. If the leak is between the crankcase and the seal, you could apply a little sealant to the outer edge before fitting it, having first thoroughly cleaned the hole into which it fits. give it a try, what have you got to lose?
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Enjoy yourself, its later than you think

[scotto75]

I’ve had the bike a couple of years now and done over 3000 miles on it commuting every day without a hitch, but this oil leak started last year and I haven’t got a clue how it started. There was a judder from the bottom end once, but no unusual noise, or vibration in the footrest, and when I first replaced the oil seal I couldn’t notice any play in the shaft either.

Thanks for the advice Neptune. I’m currently getting a CB250 up together for an MOT, at which point the plan’s to take the CG off the road and rebuild the engine as a learning exercise, so for now trying another seal with some sealant may be a temporary fix to stop the little pools of oil every time I rest the bike up.

Just to clarify, which way should a seal be fitted, with the spring side facing outwards or in towards the engine?

[bikenut]

Lip seal riding on crank to stop engine oil from leaking into oil free "outer chamber" where the flywheel is, usually spring to oil side, is breather blocked ??
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