Fixing the infamous 'right above the exhaust' leak

If it's broken or just needs tweaked

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Postby Chris » Mon Jul 23, 2007 10:31 am

You've probably already looked into this, but I noticed a while back that when I'd lube my chain it liked to sling lube around inside the cover which then migrated out along the shifter shaft and anywhere else it could. It would even drip down onto the exhaust heat shield and cook. Also, it could be found all over the frame and foot peg. It was a terrible mess.

Since then I've replaced my chain with a new o-ring type and use 'chain wax' spray to lube it. I've had the cover off and cleaned it and there's no more 'leakage' near my left foot.

Chris: I'm glad to hear that you've chosen to keep your CB650 :) If we start planning and saving our dough now, maybe we could have a 'World CB650 Rally' in Pittsburg, PA around say... 2020 or later? :lol: I was driving East along I-86 yesterday and thought how much I'd love to share these roads with our friends in Europe. Not particularly THAT road, since it's way too bumpy for our bikes, but the scenery is awesome. However, the road has just recently gained its interstate status and by then it should be smoother. The interstate conversion of PA Rt. 15 out of Williamsport should be done by then as well. We could ride north on that, west on I-86, and south on I-79 back to Pitt. Hmm, I started this as a joke, but... :lol: :lol:
1980 CB650c

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Re: Chris

Postby ShadeScribe » Sat Apr 17, 2010 2:28 am

Thank you for mentioning the chain... I just adjusted my chain, lubricated it and took it for a ride, I came home only to find what looked like my shifter seal leaking all over my heat shield. So I came here planning on having to do a lot of dirty work to fix it only to find it was just the chain lubing.

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Re: Fixing the infamous 'right above the exhaust' leak

Postby CanCB650 » Fri Aug 25, 2017 3:52 pm

Volker_P wrote:Hey Chris, which reason to still care for CB650 engine leaks? :D

One should mention again that the seal itself is in the engine casing behind the sprocket cover.
I once had oil there from the oil pump cover (also behind sprocket cover). Then it comes out below the three fins of the sprocket cover. In the picture it would be at the level of the front bolt of the exhaust protection
So have a close look where it really comes from to avoid unnecessary work.
To the oil pump: The oil pump cover has a square cross section O-Ring but a slightly oversized circular O-Ring also does the job perfectly since a long time. The original (Phillips) bolts are hard to get out and should be replaced by something reasonable.


I keep seeing reference to the o-ring being 46x3mm. Do you happen to know if this is the ID/OD measurement? I can't seem to source an original honda part so I was looking into alternatives.


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Re: Fixing the infamous 'right above the exhaust' leak

Postby tario » Wed Aug 30, 2017 4:47 pm

I'd say 43 is the OD and 3 is the thickness. You'd need calipers to get the ID. I just went to the honda dealer and ordered one. That was a year or two ago but I'd bet they still have it.
1979 cb650
1980 cb650

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