Contamination around cams / valve buckets (pics) - what is this crap?

[BSwem72]

Friends,

I recently pulled the head and cylinder block off of my bike (1982 GS1100 2v) to fix a leak at the front center of the crank case to cylinders (crappy paper gasket).

I'd like to share with you all two of the issues I found for your comments and guidance.

1) Contamination in the head / cam area. What is this stuff? Looks like there's fine dirt in there. I've smudged it with my finger right on the opposite side of that valve bucket:




2) I just replaced the little black cap on the cam chain guide. This is 200 miles of wear. Also note that black smudge stuff isn't in these two cam/bucket interfaces, unlike in the above picture:



So I have crap in the head by the valve buckets (but only some of them) and a worn chain guide after only a few miles.

What's causing the mess? Any theories? Bad valve guide seal? Worn out / miss-set chain tension? Close? Way off?

Trying to keep the old girl on the road - I appreciate your help in advance.

Brian

[5150/gs]

Looks like dust from the worn chain guide, nothing alarming I don't think.

[Nessism]

Something wrong with the cam chain if the guide is worn that much. You might want to check the chain for stretch, and verify the tensioner is working properly.

[GSEScraze]

is it as dry as it looks I see oil all but in that bucket ? if so the oil may be washing the same out of the other buckets

[JTGS850GL]

That is way too much wear for 200 miles. It explains the black stuff, but not how the cam chain guide got that way.

[BSwem72]

Exhaust side only

Looking again at the contamination, two points:

1) A lot of the oil is out of there already from pulling the head and moving it around. When I pulled the valve cover the levels were pretty even over each valve bucket.

2) The contamination is mainly on the exhaust side only. Anything to this, or is that where it would end up based on the direction the cam chain rotates?

Thanks for the help.

[Chris G]

Not sure which is left/right from the pic, do you leave the bike on its side stand? Could explain why most of the mess is at one end.

[JTGS850GL]

Personally I'd be less concerned about where the mess is and more concerned about how it got there.

[BSwem72]

To Chris G above: Bike sits on center stand. While this picture is one end of the exhaust cam, all the exhaust cam journals look like this one (same crud in them). Intake side is clean and looks normal.

Time to post another pic of what the crap might be:



Yes, that's what happens when you place that square rubber o-ring on the head gasket because you haven't found another place for it. NO idea what I was thinking when I put this together (it must have been late). 200 miles later, I have a base gasket oil leak, so I pull the head to find this.

Think all that contamination could be that burnt crap riding up the cam chain into the head?

[BSwem72]

Next step is to check the head for warp as soon as I get home from work. Fingers crossed it's still reasonably straight.

[BSwem72]

Head and cylinder block are verified straight (thank the GS Gods), and new OEM base gasket arriving this evening.

Any advice on reinstalling the cylinder block? How does eveyone keep their pistons straight in order to drop the block on without damaging the rings?

[Steve]

Any advice on reinstalling the cylinder block? How does eveyone keep their pistons straight in order to drop the block on without damaging the rings?

My Clymer manual shows how to make a block to hold the piston. A piece of wood that is cut narrow enough to go between the cylinder studs and has a slot to straddle the connecting rod. Sort of like a wooden tuning fork without a handle.

You only need two of them. Start with #2 and #3 pistons up, slide the blocks under them. Drop the cylinders down, work the rings into the tapers on the bottom of the liners. When the cylinders are fully over the rings on 2 and 3, move the crank a bit to give enough clearance to pull the blocks out, then turn the crank slowly to lower the cylinders over 1 and 4.

.

[uk gs nut]

The wear on the chain guide could be that its mounted upside down. Check its up the right way up by looking at your old one, it will have witness marks on it from the chain.

[BSwem72]

The wear on the chain guide could be that its mounted upside down. Check its up the right way up by looking at your old one, it will have witness marks on it from the chain.

Much appreciated - I will check this when I get home.

[BSwem72]

Head is back on. I used a VERY light application of permatex copper around an oem base gasket (light coat top and bottom), also a non-OEM head gasket, but one with metal crush washers around the cylinders, so my fingers are crossed.

There's a hairline bead of permitex showing front and center of the base gasket, so hopefully that'll take care of my leaking problem that led to this whole tear down.

Waiting on new exhaust fasteners and chain guide triangle (not sure what that little plastic part is called) before further assembly. I'll keep you posted.