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R100RT 1990 oil leak from pushrod tube

Bob 1642

New member
The oil leak from the left hand pushrod tubes is getting worse and I don,t want to fix it untill winter. Is there any thing I can do in the interm I find if I use the center stand the drip is less. Were is the best place to buy a exhaust nut wrench as I will need one to do the repair?
 
I just put my top end together, and I think my LHS seals didn't catch right, so I've been thinking about this:

There are only 4 nuts holding the cylinder on (one for each stud, on top of the rocker arm shoulders), and if the pistons are at the bottom of the stroke and you pull them with the cylinders, I think you can pull the cylinder off far enough with piston in place to either adjust or maybe even replace those rubber bits without pulling the piston out or upsetting the ring seating (which turns into a much bigger job with the head coming off, and so a head gasket, and honing to get the rings to set).

The rubber bits are only a few bucks at a BMW shop, OEM, and they slide right on/off (esp. with some WD40 or other spray lubricant).
After putting the cylinder back on, it's just tightening the four nuts to spec (my 1980 is 35-38 ft lbs) and adjusting your valves back to spec.

But again, this is all theoretical, because I haven't done it yet. YMMV.
 
It works:)

Done it several times, no issues. You CAN do the above replace the rubber seals without disturbing the rings/pistons and even the head gaskets are not compromised. AND, if the bike sits at all, not being used a short week or so, the seals love to start leaking. The tool for tapping them back in place is easy to make from pipe or even plastic heavy PVC. Tapping these seals takes all of 30seconds, all4 of'em and usually makes the leak stop and riding the bike every day will prevent the seals getting lazy and cold and leaking. I carry my home made tool in the bike tool box. Randy
 
I dont think the tapping down of the ring applies to the later bikes. Once you disturb the base o-rings you will have leaks, not a good idea. Wait until winter and do it right!
 
Where did you get the 35-38 ft lbs to torque the cylinders? that seems very high.
I have always been told not over 25 ft lbs.

Ed
 
Sure glad I posted my torque. Indeed, I got my units backwards. Looks like I'm the engineer that crashed the Mars lander.

In other news, I did get the rubber seals off and on for one side using the method I posted above. The one thing I didn't mention see: the exhaust/carbs come off too. It's easy as pie after that.
 
Crisco....

I've used crisco sparingly when installing my pushrod tube seals, slides right in no pinching. No leaks even years later and many miles. Running a R60/6. Go figure, I learned that from an old airplane engineer that used to work on Hamilton Standard props. The Mrs.. doesn't like it when Im rummaging about the kitchen looking for stuff.....she stays out of the garage, I stay out of the kitchen:fight.
 
leak from the left hand pushrod tubes is getting worse and I don,t want to fix it untill winter.
====================================================================
Lean bike over substantially onto something to the right side
Clean area around the leaking rubber parts thoroughly with spray brake cleaner
Apply 2 or three layers of product Hondabond or similar to cover rubber and area on block
about 1/2 inch outward from the leaking rubber - build up a big mess of this product in layers
looks like hell but sometimes will last for quite a long time/mileage

Purists on the forum please forgive me
 
Since it takes about 30 minutes for a complete fix, why waste time with a temporary fix?

agreed. sometimes, those "big jobs" in our heads that have to wait for winter are not really so "big" after all.
unless you have some truly major undertaking that also is going to be done at the same time.. take an afternoon, do it right, be done with the annoyance, and save winter for sampling new beers.
 
leak from the left hand pushrod tubes is getting worse and I don,t want to fix it untill winter.
====================================================================
Lean bike over substantially onto something to the right side
Clean area around the leaking rubber parts thoroughly with spray brake cleaner
Apply 2 or three layers of product Hondabond or similar to cover rubber and area on block
about 1/2 inch outward from the leaking rubber - build up a big mess of this product in layers
looks like hell but sometimes will last for quite a long time/mileage

Purists on the forum please forgive me

while nolt the best fix, I am sad to say, things like that work.
One of my previous bikes, the p.o. had a pushrod seal begin to leak bad while he was on a long road trip, he took JB weld and covered the seal and mating surfaces. his intent was to fix it correctly when he got home. He did not, and when I pointed it out on a pre-purchace inpsection, he said oh yep, that happend years ago. I let it go for the rest of that summer

so sad silly tricks like hondabond, yammabond, or jb weld will work
but my preference, if you got a a day and th emoney for the parts, , just do it right and forget it
 
One of the easiest . . .

Of all the projects on bringing my '93 R100RT back into shape, tube seals were the easiest. Maybe a 4 hour job.
Campbell Tellman II
:thumb
 
Push Rod Tub gasket

There is no need to pull the pistons out of the cylenders. Pull the heads up to the point you can remove the wrist pins. Then pull the cylenders off with the pistons still in them.
 
I dont think the tapping down of the ring applies to the later bikes. Once you disturb the base o-rings you will have leaks, not a good idea. Wait until winter and do it right!

That's correct, tapping doesn't apply to anything from the 1980s on.

And yes, if you have an o-ring sealing the cylinder to the block, you'll want to replace it. This applies for sure to the original poster's bike and for all bikes since maybe 1978 or so. You may want to search for hylomar with respect to this, too.
 
Rubber push rod tube seals.

question: A thin smear of gasket seal on the rubber tubes at assembly? Or would that cause the tubes to pull free of the heads as the temps change? I am getting ready to do the same job on two bikes.
 
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