1998 R1100RS Head Gasket question

[CleanGene]

Have been noticing oily buildup on the rh side of the engine block and the source appears to be where I'd expect to find a cylinder base gasket. It's not leaking enough to leave anything on the floor or where I park it (yet), but I've yet to see a 'leak' get better without doing something about it.

I would suspect a cylinder base gasket (and maybe head gasket too) but the two online parts fiche I've seen don't list a cylinder base gasket. Head gaskets, yes. And I'd replace it as long as I was in the neighborhood. Chances are this is original equipment but just curious if there truly is or is not a cylinder base gasket and if there is, where is a good source?

This looks like a project that will probably wait until the end of the riding season up here in Wisconsin, which probably isn't that far away.

 

[robsryder]

A few years ago, while at the Ga Mtn Rally, I noticed an oily and grime covered accumulation on the lower right side of the engine of my 94 R1100RS. If this would have been an airhead, then I would have suspected pushrod seals. But no pushrod seals on the oilhead. I obtained a set of head gaskets - these have been improved since my R1100RS was new. It was pretty easy to remove the head and gain access to the head gasket. I decided to remove the cylinder "while I was there".

The cylinder base does not use a gasket. I used a three-bond sealer (e.g., hondabond, yamabond, etc.). I also removed the piston as it and the cylinder head needed to be decarboned. For decarboning I used a bit of carb cleaner and a nylon brush (on an electric drill).

The cam chain was secured with some wire. All surfaces were cleaned. ThreeBond sealer was lightly applied to the base of the engine and cylinder. The new head gasket and head were replaced. The manual gives a specific torque procedure. I was using my Snap-On torque wrench, following the procedure (the last steps use angle rather than torque). At about 80 of 90 degrees on the second angle tightening on the upper forward (right as viewing the cylinder) I heard a loud "BANG!". The stud attached to the engine case pulled loose - the aluminum threads sheared from the engine.

The head and cylinder were removed. I used a heli-coil to repair / restore the threads in the engine case. I used the cylinder as my guide for drilling out the hole for the heli-coil. (If one has ever made a similar repair to an airhead, this was easier as the oil port is not the same as the stud hole.) The stud was reinstalled to the same depth as the other three studs. The piston, cylinder, gasket, and head were replaced. All head bolts were torqued following BMW's procedure - no problems this time.

I then did the same procedure to the left side of the engine. No issues with retorquing the head bolts.

After riding for 500 miles, the head bolts were retorqued. This was a few years, and thousands of miles, ago. No more leaks.

 

[jrogers]

All of mine show a little seep type stain but nothing like a wet drip. I thought it was pretty much normal for these engines. It's an area where it's never been cleaned in 30,000 miles on four of the bikes and 45,000 on two. Not planning on doing anything about it. Do you use synthetic?

 

[CleanGene]

Thanks everyone for the replies.

I do use full synthetic, I have since I've owned the bike (about 5 years) and I believe I'm the third owner. Not much for maintenance records for the period before I took over.

It's not serious enough to call it a leak as it doesn't mark its spot when parked (like my vintage British Iron does from time to time) but there's some accumulation under the cylinder and onto the block. I thought I might tackle the problem this winter. I don't seem to be losing any appreciable amount of oil so it's not something that I need to tackle before the end of the season.

When I learned there was no cylinder base gasket, I was curious about what kind of sealer people use on that area

Thanks again

 

[gsaddict]

There is no base gasket.
Carefully apply Locktite Ultra Grey SWilicone Sealer or Yamabond Gasket Liquid Gasket
Care is to be taken around the oil passage holes. Do not apply excessive amounts.
Replace the 2 small rings on each side as well.