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Hi All,

I'm in the process of restoring an 81 r100 and have just got the engine running. When I got the bike fired up there is a major oil leak from both cylinder heads, it was so bad it was dripping from there. Definitely the head gaskets and not the rocker covers or anywhere else. I machined the heads on my Bridgeport milling machine and used brand new head gaskets. I've pulled it apart to check, the gaskets were in the correct way and both the head and cylinder appear flat from checking with a precision bar and feeler gauges (the cylinders are still on the bike so was hard to check with the studs in the way).

The only thing i can think of is the head gaskets are junk. They were an old stock set made from asbestos (I can't remember what brand they were). What I did notice is neither the oil feed stud holes or the pushrod tube holes are o-ringed like in a lot of other gaskets brands. Anyone else come across this before? Any ideas of what it could be other than those seals?

(Aftermarket r90 gasket on the left, the troublesome r100 gasket on the right)

I have always used OEM head gaskets with no problem. Make sure the base O-rings are renewed also.

I've never seen a gasket without sealing rings for the pr tube and engine studs?

ME 109 wrote:I've never seen a gasket without sealing rings for the pr tube and engine studs?

99% of the gaskets I saw had those sealing rings too, that's why I thought it's the only thing it could be causing the leaking.

PAS wrote:I have always used OEM head gaskets with no problem. Make sure the base O-rings are renewed also.

I assume oem gaskets have the sealing rings? I picked this gasket set up a while ago all the other gaskets and seals looked really good. It was an old aftermaket set, back from when they used asbestos. Yep used new bmw push rod tube seals

You know, there are a couple of short tubes pressed into the head where the push rods go through headed for the long push rod tubes mounted in the cylinders. These have been known to leak and make it appear the leak is from the head gasket. I would think that gaskets without sealing rings would just weep not drip. Also make sure that your crankcase vent is doing its job. Sounds like you may have excess pressure there.

George Ryals wrote:You know, there are a couple of short tubes pressed into the head where the push rods go through headed for the long push rod tubes mounted in the cylinders. These have been known to leak and make it appear the leak is from the head gasket. I would think that gaskets without sealing rings would just weep not drip. Also make sure that your crankcase vent is doing its job. Sounds like you may have excess pressure there.

It's definitely coming from the head gasket. I could see it getting wet the whole way around the head gasket, so probably just coming from where the oil feeds go through the gasket. The engine had just been painted so it was really obvious where oil had ran. I think excess crank case pressure would cause oil to come from every other seal and gasket before it pushed through the head gasket. It certainly wasn't leaking coming from any other seals.

I finally replaced the gaskets with genuine ones and fired it up. No more leaking! It goes to show not all gaskets are created equal!