Heartbreak of head warpage

[nhmaf]

I decided to get out in the garage and do some tuneup work on the the "new" 1978 R100/7 that I bought last November, but which I had done little on except buying an underseat toolbox and toolkit for it since then.  It was hard starting and wouldn't idle well, AND from the plugs' appearance and smell of the exhaust was running WAY too rich.  Obviously the PO didn't know what he was doing with it, and his claim of having MAX BMW going through the bike from front to back the previous year was now very suspect.   Great...

I pulled the valve covers off to check the valve clearances - left side was .004 intake/.006 exhaust, and the valve cover was upside down, .ie. it was the right side valve cover (RECHT).  The right side valve clearances were actually 0/0 - YIKES, no wonder it wouldn't run well!  Of course, the valve cover was also upside down/opposite side (LINKS).  I had a set of new valve cover gaskets - the old ones were out of position and munged up.  

I reset the valve clearances (.004/.008) and triple checked both sides.   I went to put the covers back on the proper sides with new gaskets and discovered that the wouldn't seat/draw tight enough to close the gap and compress the gasket on the bottom side. I could tell visually that it would  leak.  Flipping the covers back to the INCORRECT sides seemed to close the gap and may seal properly.  So, it seems that maybe the heads are warped and the covers were swapped intentionally as they happened to seal better that way. Argh.

It became too late and chilly tonight to persevere, so I'm going to give up for now and resume the project on Tuesday - starting with retorquing the heads and readjusting the valves - not likely that this will solve the problem, but at least I'll know the baseline is correct and will pray that I don't pull a stud while retorquing the heads.    I'm also going to order a set of those thicker gaskets from realgaskets.com and plan to go that route for the short term.

I suspect that I may be pulling the heads for valve work in a year or two -will have to watch the valve clearances as I go.. Iwill plan to have the surfaces milled true at that time, I guess.

[Rob Valdez 79 R65]

Wow - when I read the title I thought you meant that the head-to-cylinder surface was warped!  Much more serious.

Too bad about the guy lying to you about the MAX BMW thing.  Did he have receipts?  It's hard to believe they would have installed the covers backward intentionally without at least making note of it on the service receipt.

I recommend Bob Grauer in the SF Bay area.  He does great work, as do a few others.  I plan to have the heads of my latest engine done by him either this next winter or the next, depending on how my employment pans out.  I don't know that they need it, but since it is a '81 engine, I suspect it will.

[Barry]

.... and will pray that I don't pull a stud while re torquing the heads.  

That's one job guaranteed to create fear in the gut. I hate doing it.

Is it me or do those nuts seem to turn for ages before the torque wrench finally clicks as I creep very cautiously up to 25ft/lbs.

[nhmaf]

.... and will pray that I don't pull a stud while re torquing the heads.  

That's one job guaranteed to create fear in the gut. I hate doing it.

Is it me or do those nuts seem to turn for ages before the torque wrench finally clicks as I creep very cautiously up to 25ft/lbs.

I aim for ~23 ft pounds and stop there.  Though this reminds me to get another torque wrench, too.  I've tended to favor a beam torque wrench as they have few parts to gowrong, but there are times when it isn't easy to see/read one while tightening things down, and a clicker wrench is the ticket for that.  Leastways, with (2) wrenches I could do a "sanity" check with the other - though what do I do if they disagree ?  Hmmm... maybe I need THREE torque wrenches....

[Justin B.]

Your head might not necessarily be warped, could be the cover.  Pull the studs out of it and see if it will lay flat on a piece of glass.  If it doesn't you can put down some sandpaper and "lap" it back true...

[nhmaf]

It is possible that the cover(s) may be warped, but for the near term I've decided to just order a set of those silicone gasket sets from realgasket - I'm hoping that they are thick and squishy enough to do the job with the left and right covers back in their proper location.. after this, I've got to find out why there is a leak from the oil cover - I'm expecting/hoping that it was improper use (or lack of) the shim, gasket, and o-ring thing... (fingers crossed)

[Justin B.]

Two of the bikes I've gotten over the past several years had leaky filter covers and both were fixed by removing the paper gasket.

[Rob Valdez 79 R65]

Two of the bikes I've gotten over the past several years had leaky filter covers and both were fixed by removing the paper gasket.

And replacing with silicone gaskets?

I've successfully used two OEM gaskets before, doubled up.

After my heads came back from being rebuilt, they didn't leak at all!  I asked Bob Grauer if he had done anything, and he said no.
Although he did helicoil both center stud threads gratis.  

[Justin B.]

Rob - "...leaky filter covers..."

[Rob Valdez 79 R65]

Rob - "...leaky filter covers..."

Oh yeah  

I had the same experience/results.  But that was before I discovered the method of measuring the canister depth.

[marcmax]

I have been using the silicone gaskets for a couple of years now. I can tell you it doesn't matter if you put the valve covers on left/right, right/left, upside down or inside out. The silicone is thick enough and soft enough to fill the gaps and not leak. I was kind of hoping they would eventually wear out so I could replace the red ones (they were all initially red silicone) with a black or gray set so they are not so prominent but after about a dozen removals they are still as soft and pliable as the day I installed them.

[nhmaf]

Yay, the new gaskets are here!  And, I ordered Black ones !  Hopefully they are just as thick and squishy as the red ones - I think I'm gonna need it..

[Teo]

After noting mysterious oil stains/burns on the right header and smelling burned oil over a long period of time I finally discovered the right valve cover was leaking on the forward upper side.  The gasket had shrunk in.  A new gasket solved the leak but there is a vague misting there still.  

That section of the cover was apparently not pressing hard enough on the gasket which shrank over time.  I unscrewed the studs and lapped it on 320 sandpaper laid out on a sheet of glass.  Now it seals fine.

Teo