Author Topic: CB77 - clutch rod oil seal  (Read 981 times)

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Offline Bodi

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CB77 - clutch rod oil seal
« on: April 18, 2019, 04:44:14 AM »
After the spring startup the bike started dumping its oil on the floor from the right cover. I removed that and started it to find the source. The clutch rod and its oil seal in the sprocket shaft slowly came out along with much oil, with the oil pressure pushing fairly hard on the rod.
I cleaned the seal and bore and reseated it. The rod still walks out when running, force increases with higher revs.
I can't remember that happening before, I have run these engines a fair bit with that cover off.
The manual has an oil flow diagram but it is not very detailed.
Now I'm leery of riding it. If the seal pops out again, oil would drain rather quickly and maybe destroy the engine before I crash from the lubricated tire.
I plan on replacing the seal, maybe use some loctute or whatever on it. Does anyone know it the oil pressure hitting the seal and rod is normal, or should I look for passage blockage or an oil pump relief valve problem?

Offline jack58

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Re: CB77 - clutch rod oil seal
« Reply #1 on: April 18, 2019, 07:27:13 PM »
you mite want to check your vent tube to make sure its not stopped up that can cause presser in the crank case just a thought

Offline jgger

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Re: CB77 - clutch rod oil seal
« Reply #2 on: April 18, 2019, 09:59:34 PM »
I burnt the motor on my CL72 (250 Scrambler-same set up) the center stand stopper would pinch the breather with the stand up. Check or replace the breather tube from the back of the head. If it is clear there should not be enough case pressure to pop that seal out. A little gasket sealer applied to the O.D. of the seal is almost a must.

You could remove the dip stick and blow some low pressure air in the oil fill tube and see if it escapes through the breather out let.

That or you have a serious blow by condition in the cylimders.
« Last Edit: April 18, 2019, 10:01:46 PM by jgger »
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Offline Bodi

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Re: CB77 - clutch rod oil seal
« Reply #3 on: April 19, 2019, 03:26:03 AM »
Same with fill cap open. It is oil pressure.

Offline bert96

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Re: CB77 - clutch rod oil seal
« Reply #4 on: June 08, 2019, 01:15:59 PM »
This is a well known problem for the cb77. You need this part.

http://www.cappellinimoto.it/catalog/motorbike/CB77/product/117A

Bert
QA50 1969,ST-90 1974,mb5 1982,rz350 1983,shadow 1100 1985,vf1000f 1985,BMW K1 1990,shadow tourer 1100 2001,vfr 750 1994,vtr250 199?