Head Oil Leak After Rebuild

1980 Cb 650 Custom. I recently paid a shop to install new rings/valve
stem seals/lapp valves. They charged me for a gasket kit. It leaked in
the valve body area before and also after the rebuild. I cleaned the
whole area the best I could and took it to another motorcyacle shop
and even they cant tell me really where it is leaking from.
Does anyone have any ideas as to what can be done to get this leak
fixed. I am going to take it back to the person that did the top end,
I wonder if he forgot to put in a few o-rings somewhere.
I have heard of coating the top with powder and see whare it leaks
etc, but maybe the best thing to do is to take the valve body off and
start again?
Advice appreciated.
Thanks.
Tim C.

 

Tim C,

Could be the a warped head. Just a WAG.

Ride safe,

Manjo 1500A9

 

It leaked in the valve body area before and also after the >rebuild. I
cleaned the whole area the best I could and took it to >another
motorcyacle shop and even they cant tell me really where it >is leaking
from.

In the case of a real leak, you will see where a stream of wet oil has
run down the front of the engine, usually. But weeping oil is a
unesthetic nuisance that doesn't really justify disassembly and repair,
just occasionally wiping the oily film off the engine...

Why did you take it to another shop? Didn't you get a warranty on the
work done in the first shop? Or did you let the warranty on parts and
labor expire?

You have a right to expect the work you paid for to be done thoroughly,
at least for the limited warranty, and getting a motorcycle back that
leaks fluids after being worked on indicates that the work was done
incorrectly...

I wonder if he forgot to put in a few o-rings somewhere.

I wouldn't tell the original mechanic that I had taken the motorcycle
somewhere else. He might claim that the other shop was at fault...

It is very possible that o-rings were lost or forgotten during the
disassembly and reassembly process. Mechanics are in a rush to get work
out of their shop so they can make money for as little time spent as
possible. I looked at the the drawings at www.partsfish.com, and I see
that the valve cover has three gaskets on top of it and a gasket
underneath it. They look like the rubber gaskets on my GSXR, which are
supposed to seat in a groove in the cover. If the mechanic doesn't glue
the gaskets to the covers, they can slip during assembly, and then they
will leak...

It's also a good idea to apply a thin film of silicone sealer to the
flat side of rubber gaskets like that, to prevent unesthetic oil
weeping...

Also, the tachometer drive assembly has an oil seal and rubber o-rings.
I had the oil seal leak on my GS-1100, and it wore a groove on the
shaft that drives the tach cable, so I had to polish the groove out
before it destroyed another oil seal and leaked again...

Blowing talcum powder (like after shower talc) out of a plastic bottle
onto an area where there's an oil leak sounds like a really good trick.
You should spray gunk all over the area where the leak is
at, hose the engine off with water and let it dry good before applying
the talcum powder and starting the engine. The worst thing that could
happen with talcum powder is that it blows away when you ride the
motorbike...

But, I wouldn't recommend having the shop remove the cylinder head
until you've checked out those gaskets, oil seals, and o-rings in the
valve cover, the valve adjustment covers, the oil/air separator, and
the tach drive...

If the leak is lower, down around the head gasket, maybe just
retorquing the cylinder head will stop the leak. The original shop will
probably do that anyway, before committing their time to removing the
cylinder head a second time...

So, if they tell you that's what they did, ride the bike right away to
see if it leaks when it's warmed up. Don't let your parts and labor
warranty run out before it's fixed...