Compression problem identified....need your expertise :-)

[Anonymous]

Recently I've found out that one of my cylindars was down to around 90..after a compression test. It should be in the 130-150 range. Originally, we thought it might be a stuck ring...the reasoning was that the other three cylidars were fine. But what we saw last night leads me to believe otherwise. When the bike was started, my uncle noticed bubbles of air coming out of the head gasket (in the very area of the troubled cyclindar). I bet a million bucks THAT is the reason for the low compression!

Any thoughts on this? Could a head gasket leak cause low compression?

:-)

Rudi

[daveo]

Re: Compression problem identified....need your expertise :

Any thoughts on this? Could a head gasket leak cause low compression?

:-)

Rudi

Shore as shootin' pard!!!

[Anonymous]

You definitely want to re-torque the head..
It may stop the leak. As for any damage caused to the head gasket by the leak.... well. I'd stay sort of close to home with the bike for a while just to see if it's going to hold.
You probably want to schedule replacing it but you might be able to hold off until the cold weather returns. All sort of depends on the outcome of re-torquing the head and how "adventurous" you feel.

[Anonymous]

You definitely want to re-torque the head..
It may stop the leak. As for any damage caused to the head gasket by the leak.... well. I'd stay sort of close to home with the bike for a while just to see if it's going to hold.
You probably want to schedule replacing it but you might be able to hold off until the cold weather returns. All sort of depends on the outcome of re-torquing the head and how "adventurous" you feel.

Pete,

Correct me if I'm wrong...but won't I have to take off the Valve Cover to get to those bolts that need re-torquing? If that was the case, shouldn't I just go ahead and replace the head gasket while I'm in there? Wondering what your take is...

Thanks!

Rudi

[KGB]

IF..big IF it is the head gasket, you may also want to verify that the deck and head are not warped.

Find a straight edge, preferably metal, and palce it across the head and deck, where the head will sit on the deck/block.
If either of them are warped I would plane BOTH to insure a tight seal.
It's not a lot of $$$, just time. Any good machine shop should be able to perform this.

What kind of gasket ? Fiber or copper?
I use copper on my 1000S.

[Anonymous]

You definitely want to re-torque the head..
It may stop the leak. As for any damage caused to the head gasket by the leak.... well. I'd stay sort of close to home with the bike for a while just to see if it's going to hold.
You probably want to schedule replacing it but you might be able to hold off until the cold weather returns. All sort of depends on the outcome of re-torquing the head and how "adventurous" you feel.

Pete,

Correct me if I'm wrong...but won't I have to take off the Valve Cover to get to those bolts that need re-torquing? If that was the case, shouldn't I just go ahead and replace the head gasket while I'm in there? Wondering what your take is...

Thanks!

Rudi

Yeah, the valve cover does need to come off to re-torque the head.
As for going ahead and changing the head gasket, yeah it should be done, but it's quite a bit more work than just the valve cover and I know I'd hate to be staring down at that bit of work with the riding season just starting. So if could be put off... so much the better, but certainly not if it's something that could lead to damage to the engine.

[Anonymous]

IF..big IF it is the head gasket, you may also want to verify that the deck and head are not warped.

Find a straight edge, preferably metal, and palce it across the head and deck, where the head will sit on the deck/block.
If either of them are warped I would plane BOTH to insure a tight seal.
It's not a lot of $$$, just time. Any good machine shop should be able to perform this.

What kind of gasket ? Fiber or copper?
I use copper on my 1000S.

I'm not sure...what kind of gasket is "best"?

[KGB]

I use the copper ones because they expand and contract with the base and head.
The fiber doesn't, it's a bunch of paper pressed together, so it doesn't expand.

Copper is more money, but I haven't replaced one in about 10 years and no leaks

[Dink]

Rudi try re-torqueing first as lifting the head also means you have to remove the block and repkace the orings at the botom of the block and the base gasket,and generally one thing leads to another. So I would try re-torqueing to see if that will repair it until winter when you can then fix it .
Dink

[cbxchris]

The new cometic spring steel fiber gaskets are good....much better than a few years ago. Personally I would use a stocker due to the oil galley leaking with copper. Its not uncommon for a GS 1100/1150 to be 3 or 4 thousandths off at the cam chain galley ....usually requiring a head and cylinder redecking. If you can find someone that grinds them instead of fly cutting on a mill thats the way to go. The finish is so much better. Be careful over torquing stock studs and nuts.

[Anonymous]

Can someone tell me what the product number is for a head-gasket and valve-cover gasket (for my 1980 GS1100E)? Thanks!

Rudi

[Anonymous]

I have been using www.bikebandit.com for most of my parts needs, I am sure there are others. that way I can sit on my couch, drink beer, and wait for it to come to me. They will have the part numbers

[Anonymous]

Rudi,

My opinion is that you should remove the valve covers and re-torque your head. Please refer to my recent post in the tips section under the proper way to re-torque your bolts. Note your break-away torque and look for discrepencies. If the break-away torque is not the same for all fasteners or is very low for all the fasteners, this will indicate a loosened fastener.

Re-check your compression and verify a proper seal. I would recheck compression every couple hundred miles until you're confident in the fix.

I would suspect that simply re-torquing the fasteners may not solve your problem as these types of leaks tend to damage the gasket. Also, a "loose" head would probably cause a compression loss in at least one adjoining cylinder as the gap would certainly not be limited to one specific area. My guess is that you blew a head gasket and a visual inspection and gasket replacement may be necessary anyway.

Try the quickest and easiest fix first and cross your fingers. Good luck.

[jpaul]

It should only take one weekend to replace the head gasket and the valve cover gasket. I would go ahead and order the parts and just do it. If you need pages from the factory manual copied, let me know. I work in Strongsville and Seven Hills isn't too much of a detour on my way home.