Need help with boxer motor

 

I have a (more or less) BMW R65 clone motor on the Dnepr. The other day
I over-revved it (by doing 51 mph) and now there's an oil leak. It seems
to be between the pushrod tubes and the motor block. The tubes terminate
in some kind of black plastic(?) boots which fit into machined recesses
in the block. The oil sprays out between these boots and the block.

Any help appreciated
TIA, Sean Q

'06 Zuk S40 / '85 Dnepr MT-11 / various bent bikes in triage

 


Please bear with me, as I'm thinking BMW not Dnepr.

The black rubber boots are humorously called pushrod "seals".

Most likely you got it hot and it began to leak.

If the rubber's gotten dry and brittle, the seals need replacement.
You can sometimes cobble up a fix by wrapping plumbing type
string between the seal and the metal flange on the pushrod
tube shich pushes on it.

If you do replace it, try a little Hylomar or equvalent on the
outside of the rubber. Get a parts diagram before you  open
it up so you can see what you're dealing with.

If you need to replace a cylinder base gasket or O ring(s), you'll
need to completely remove the cylinder. If not, you might be able
to just separate the cylinder from the block, slip the pushrod seals
in place and button it back up again.

http://www.google.com/search?hl=en&q=airhead+pushrod+seal+leaks&btnG=Search&aq=f&aql=&aqi=&oq=

Mostly they tell you to replace them.

I usually live with minor leaks until I can't stand them and
they're leaving drippings when I park. I've got a small one
now that I'll eventually have to deal with. If it's appreciable
amounts of oil on your boot or driveway, you might's well
fix it.

 

Rob Kleinschmidt wrote:


That seems to be fairly common with the older bikes.  My 1971 Honda
CB100's case has a minor seep between the crankcase halves, but to fix
would require a fairly complete teardown, which I don't fancy at the
moment.

OTOH, my 1987 Suzuki Savage doesn't drip.  Must be the wonders of modern
gasketless sealants.

--
HPT

 

| If you need to replace a cylinder base gasket or O ring(s), you'll
| need to completely remove the cylinder. If not, you might be able
| to just separate the cylinder from the block, slip the pushrod seals
| in place and button it back up again.

Yes - if you pull the cylinder off the piston you really should replace the
rings. Try to avoid that.
|
|
http://www.google.com/search?hl=en&q=airhead+pushrod+seal+leaks&btnG=Search&aq=f&aql=&aqi=&oq=
|
| Mostly they tell you to replace them.
|
| I usually live with minor leaks ....

"Live with"???  Hell, they waterproof your boots!

 


Piston rings ? Why ? Or did you mean O-rings ?