Head Gasket Types & Recommendations

[jhall]

Only 1500 miles since re-torquing the head bolts, the left head gasket on my 95 R100RT is weeping again; not bad enough to start blowing in the wind like before, but enough to cause wetness. It's likely to only get worse, so I plan to replace the head gasket on that side, but have noticed the part number changed in 1992. From what I can tell, pre-92 had asbestos in them, and post-92 did not.

QUESTION: is there any difference in reliability between pre and post 1992 head gaskets? Looks like post-92 is most readily available. But if there's significant reliability issues, I will look harder for pre-92 NOS, asbestos.

QUESTION #2: Is there an aftermarket head gasket that's superior to OEM? I know there is for Harley EVOs, but not sure about Airhead. I plan to stay with OEM, unless someone here advises different.

Appreciate any and all feedback.

Thanks Much,
Joe H

 

[20774]

I would get OEM or maybe order from Tom Cutter on the east coast. Also from Tom, you'd get some pretty advice!

 

[jhall]

Excellent Advice

I would get OEM or maybe order from Tom Cutter on the east coast. Also from Tom, you'd get some pretty advice!

Your post was just the advice I needed. I called Tom, and he said no difference between pre and post head gaskets, they simply changed verbiage to satisfy some countries' requirements regarding asbestos.
Thanks Much,
Joe H

 

[stevenrankin]

Question

Joe, do you mind me asking are you talking about the head gaskets or valve cover gaskets?

I am sorry, I don't recall all the work you have done on the bike, did you have the heads off at some point or did the previous owner have them off? I assume if you had them off, you installed new head gaskets when you reassembled the heads to cylinders. If they are still leaking, even after re torquing the heads a couple of times, I kind of think something is amiss.

The BMW airhead head gaskets system if pretty easy no real way to bend, crimp or fold a new gasket by mistake. Hopefully there is not something serious preventing a good seal on your bike.

If you mean valve cover gaskets, I and my friends have noticed the latest BMW valve cover gaskets are a pain and do in fact leak. I used on my last install of new valve gaskets just a touch of sure grip gasket adhesive, very lightly applied and it worked fine to stop the problem. My friends all used various gasket sealer compounds.

One other thing I have found in the past with a couple of friend's bikes is the center valve cover gasket stud can strip out in the head and leak oil. Don't ask me how, but it does, and it tends to end up on the rider's boot. Fixing it with a heli coil solves the problem.


I am looking forward to your fix. St.

 

[jhall]

No Previous Engine Work

Hi Steve,
As far as I know no previous engine work was done. I bought the bike from 2nd owner, who got it from the estate of the (deceased) original owner. The original owner put 15,000 miles on it from 1995-2010; the 2nd owner put 10,000 on it from 2010-2020. I bought it last October, and pretty sure the valve covers had never been off of it, when I adjusted the valves after the ride home (I did not re-torque the heads then). I am nearing 10,000 miles on the bike, and after the first few thousand noticed both heads were weeping; later they began seeping enough to blow onto my pants leg and on the bike. So about 1500 miles ago I re-torqued all head bolts. The right side is still dry, but the left is weeping again.

So my plan it to install a new head gasket on the left side, and leave the right side alone since it is still dry.

This is my first experience with Airhead head gaskets leaking. I recall jug gaskets and pushrod tube seals leaking on prior Airheads, but not head gaskets. I thought maybe the 1992 and later head gaskets were possibly inferior since labeled 'asbestos free'. Nope, no difference says Tom Cutter. So I will be installing a head gasket soon on the right side. Not a major issue, but just trying to avoid any downtime later, as I plan to put some serious miles on this Airhead this summer.

The valve cover gaskets are both still OK (fingers crossed).

Thanks Much,
Joe H

P.S. When are you gonna get yours on the road? Good weather coming and Covid going, looks like it's gonna be a good time to ride!

 

[stevenrankin]

Hey Joe

Thanks for clearing up you are in fact talking about head gaskets. Well partner, there should be no reason for them to be leaking at 35K miles unless someone at the factory screwed something up and it is now biting you in the butt or, one of the POs had the engine apart for some reason. All the time I have been a fly on the wall at my local now closed dealer in the early 80's and 90's and now my independent airhead shop, I have never seen weeping or leaking head gaskets just starting to leak on their own at what is really break in mileage for a nikasail engine.

Sorry it happened to you. I think someone had the engine apart at one time who knows why. For your year bike, I very much it was done for a valve recession problem, That was solved sometime in 85. I don't know if you are in friendly contact with the second owner, maybe he could shed some light on the subject.

Anyway, you know what the problem is, and how to fix it so it should not be a problem, just an annoyance and cost you don't need. Good luck with the repair.

Well, despite dry road salt on the roads, I did get out for my first ride of the season. Not a long one, just a 100mile loop with a stop at the Beemer Barn for coffee and conversation. the BB is one of my hang outs, lol.

Bleeding health problems are kicking me right now and despite sunny days and dry roads, I am limited in riding almost grounded. Sucks sometimes getting old, at least, the problems have a good chance of being corrected, it just takes time and I am VERY impatient.

Maybe Saturday I will get a longer ride in, it depends on how I feel. Cheers, St.

 

[robsryder]

Something to check if head gaskets are leaking is that the head and cylinder mating surfaces are perfectly flat. On my 77 R100RS I had an issue with oil weeping from the 12 o'clock head stud. The issue was not cured by solely replacing the head gasket. I discovered that the head was very slightly warped.

I used a thick piece of plate glass with coarse sandpaper (80 grit initially) then going to finer grades, ending with 400 (or maybe 800) grit sandpaper. I wet the sandpaper with WD-40 and used a combination of "figure-8" and circular motions. At the outset there were some shiny (high) spots and some dull (low) spots. At the end the head surface was shiny all over. Prior to doing this the valves were removed. After de-warping the head it was washed in warm soapy water. A compressed air jet and some time in the sun were drying methods. The valves were re-installed and the head replaced (with yet another new head gasket.) No leaks. Head re-torqued at about 500 miles. No leaks since.

 

[k12lts]

If you are going to pull the head you might as well replace the pushrod tube seals too. If they are not leaking now they will be soon.