So I've had this slow oil leak between the crank case and the cylinder heads.
Finally got around to spraying it with some "Gunk" too see exactly what was going on.
Definitely oil, as the Motul 300V is neon green, and this is also.



How serious of an issue is this? I always check my oil before going anywhere and so far it hasn't moved (which is really saying something considering the drain bolt is stripped and held in with gasket sealant  )
Do these leaks tend to get worse? Or if I just keep an eye on it can I continue to ignore it. Really not even sure what's involved in having that fixed, but I can't imagine it'd be easy/cheap.

Thanks,
Wright

did you check the tachometer cable where it mounts into the engine to make sure that wasnt it?
Just asking because of the placement of where the oil was found because...

that is a very common leak (so I've heard)
Mine was slightly leaking and the oil would build up in those crevice's.

I actually just replaced the gasket for that last week too.

Its a pretty simple and cheap fix if that is indeed the problem.

(edit)
here is a link on it.
http://cgi.stanford.edu/~sanjayd/gs500/Restoration/TachometerCableLeak

Around the tach cable looks great, all dry and no signs of dripping. Definitely coming from where it looks like it is in the picture.

Another thing that just started happening for the first time today, there's like a tapping near the top of the engine? Really hollow sounding, like if you taped on a flower pot with a spoon. It only happens for a few seconds then goes away. And I've only really noticed it when coming to a stop, but that could just be it's the only time it's not being drowned out by something else.

-Wright.

The tapping is probably end play in the cam, but somebody else can go into more detail.

If the motor is designed like the GR650, there is a channel at the base of the cylinders to relieve pressure. It's only used when the crankcase breather tube is clogged - so check that first. Also, might want to torque down the headbolts (all 8 of them).

Quote from: Big Rich on July 05, 2011, 09:11:02 PM
The tapping is probably end play in the cam, but somebody else can go into more detail.

If the motor is designed like the GR650, there is a channel at the base of the cylinders to relieve pressure. It's only used when the crankcase breather tube is clogged - so check that first. Also, might want to torque down the headbolts (all 8 of them).

Well for the first month I had it, didn't even have a hose for the crank case.
But just this week I put on a hose and K&N breather...but the hose was short and to get it out of the gas tank it had to corner slightly, might have pinched?

The sound is actually the exact same shown in this video.
18 seconds is right around when it makes a quiet version of the hollow pot clanging noise mine's making.
http://www.youtube.com/watch?v=hl5byiFCNwk

Also I noticed some fresh neon green motul oil up by the top of the engine...Obviously I need to take that silver piece off and get a gasket or line it with some RTV. But is oil supposed to be getting up there regardless? 


-Wright

Holy crap that is a dirty head cover.

Your internal pressure is way too high. I thought it was from a clogged breather tube- but it looks like you have some piston blow-by. Do a compression test and report back here with the results.

I had done one earlier and I think it was something like 115-R and just over 100-L. 

Mmmm, Motul 300V synthetic in a very old air cooled mc engine, a 1990 you bought earlier this year so no way of telling actual milage on it.  You don't say what grade oil it is, 5W-40, 15W-50, or whatever.  I had an old high milage Honda CB750 that was starting to use a lot of oil about 25 years ago so I put synthetic oil in it thinking it might hold up better.  It began leaking from the cylinder base gasket like yours does as well as a couple engine side covers almost immediately when hot and I changed back to conventional oil and the new leaks stopped.  I'd change that Motul to a 15W-40 Shell Rotella T or equivelant heavy duty oil first and see how the leaking goes.   Enough said about oil, don't want to change this into another oil thread.   

Having put 80k miles on my 97 GS purchased new and having 87k miles now on my 02 GS purchased slightly used I am familiar with leaking valve cover gaskets like your last pic but not as bad.  I find they need replaced about every 30k miles, about same on both GSs.

Continued......

I think you have a camshaft knock but it's not very easy to hear on that video.  Knocks only when hot, only at idle, and goes away when you pick up engine speed to a fast idle?  If so it's probably the infamous cam knock which I first identified on this forum about 10 years ago.  You can check your camshaft end play when you take the valve cover off to replace the gasket to confirm knock source.  Have you checked valve clearances?

I have a little oil seepage from my 02 cylinder base gasket and had some on my 97 too.  Seems common enough with high milage GS engines but it's so little that cleaning off the engine at a magic wand type car wash makes it look good enough for me.  That reminds me, I'm a bit overdue for my annual bike wash so it looks pretty oily, dirty, and rusty right now but not as bad as your pics and it still runs like new.