A: Oil Pipework Summer Bodge

Monkeypants

Monkeypants

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About a month ago I removed the Rapide heads to fit new inlet seals. Unfortunately, I did not renew the lower pushrod tube seals.
A couple of years ago I had the heads off to find a loud clattering noise that turned out to be coming from a loose exhaust valve guide.
That was the the first time the heads had been removed since 2004, about 60,000 miles back.
New lower seals went in then and they stayed dry for all that time.
After removing the pushrod tubes and re installing them 2 years ago, the seals on the rear cylinder tubes started to weep a bit.
I forgot to order new seals this time around and took a chance that the existing seals would somehow be ok, accepting that they might weep a bit. It is riding season, not wrenching season!

It turned out to be more than a bit. The whole back half of the bike was awash in oil after a ten mile ride. Bad move.
The pushrod seals were positively identified as the problem.
Not wanting to remove the heads again for a proper fix, I tried cleaning the area with brake clean and compressed air, then dripped some Loctite 290 wicking thread locker on the area.
The results are from the same ten mile ride each time. I might give it one more application as it only takes a minute. One leaker is now completely dry, the other almost there.

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Jez Nemeth

Jez Nemeth

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Had similar on my first build comet -used Tribond and stopped it dead, not been an issue since. Unfortunately everywhere else I used Tribond leaks like a sieve! There's got to be some goo out there that stops these leaks, super sticky fast setting oil resistant stuff that doesn't have the potential of blocking oilways if parts break off, so leaning on the unsetting side of life.
 
Monkeypants

Monkeypants

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The 290 is Anaerobic so it only sets in the absence of air, as in the tiny space between seal and pushrod tube.
Should any drip through it should dissolve into the oil.
I'm going with that theory anyway:)

Glen
 
Jez Nemeth

Jez Nemeth

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290 what?...that sounds exactly like the stuff I've been looking for Glen. Yup I'd be stuffing and flooding that stuff in there, should do it!
 
Monkeypants

Monkeypants

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It's intended as a thread locker for previously assembled fasteners, however it seems to have some good sealing properties as well.
This fellow used it to seal oil drums.

 
O

oexing

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290 is thread locker, yes, but only for very small gaps - and mainly for metallic components.Not my choice on rubber, silicone may do the trick or a few windings of teflon tape around the shroud stuffed into the rubber seal at the top. But the engine breathing has to be effective for having no pressurised crankcase.

Vic
 
Monkeypants

Monkeypants

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I wouldn't recommend Teflon tape or silicone in that area. It could get loose in the engine and end up where it shouldn't.
The green anaerobic stuff has done the job well enough for a summer of riding, maybe more.

Glen
 
O

oexing

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Are we talking lower pushrod seals or upper ? Anyway, I did not mean to stuff teflon tape down into lower seals that much to walk into the engine. Big question is about how much crush is on shrouds by the rubber seal. In doubt some teflon tape could be stuffed around the rubber seal into crankcase recess for improving rubber grip on shroud. That can be done on bike , no risk of tape getting into engine. Also teflon tape could be wrapped around shroud at the top end for "crush seal" compressed by top nut onto shroud collar and into threads.
My choice were adapters with o-rings for lower seals, no square cross section rubbers on top and lower ends, as alignment cannot be correct with variations of lengths in cylinders and all.

Vic
 
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