Horizons Unlimited - The HUBB

Horizons Unlimited - The HUBB (http://www.horizonsunlimited.com/hubb/)
-   BMW Tech (http://www.horizonsunlimited.com/hubb/bmw-tech/)
-   -   Leaky R80GS pushrod seals (http://www.horizonsunlimited.com/hubb/bmw-tech/leaky-r80gs-pushrod-seals-7660)

Sean Kelly 25 Jan 2001 00:10

Leaky R80GS pushrod seals
 
Hi

My R80GS pushrod seals are weeping slightly and I'm wondering if anyone knows any tricks for getting them to seat without removing the heads.

Can I expect the slight weep to quickly turn into an ecological disaster or should I just forget about it?

------------------
Sean

Grant Johnson 25 Jan 2001 02:12

Sean,

The seals won't turn into an ecological disaster anytime soon.

When the bike warms up, the cylinders/heads move and expand slighty, which, when the seals are new and soft is easily dealt with and there are no leaks. As they age and harden, they are no longer able to seal properly, as they're just too hard to flex enough to maintain the seal.

They will weep for many thousands of miles, very gradually getting worse. Weeping for 10,000, even 20,000 kilometres is no surprise.

They are easy to replace when it comes time. And if someone suggests banging on the collar just above the seals on the pushrod tube, it won't work on yours. It worked on approx. pre 1980 models only - and then temporarily.

Don't worry about it until you have an opportunity to deal with it easily.

Note - if you have the topend off for any reason it's worth replacing these, as well as the o-rings on the studs. They aren't expensive.

------------------
Grant Johnson

Share the Dream!
at: www.HorizonsUnlimited.com


Timo 20 Mar 2001 12:47

The only advise I can offer on this problem concerns removing the heads and reseating the pushrods. When doing this I understand it is important to drive the pushrod guides out of the heads about 1/8th of an inch (2-3 mm). When you reinstall the heads this will force the seals to seat firmly.

shilling 29 Mar 2001 03:28

Sean,
I haven't kept up well with this discussion group, and I see your post is two months old. Everything Grant told you is true, however I've been told that tapping in the seals themselves a little bit (as opposed to tapping in the collar, which in the newer models is brazed to the pushrod tube)well stop the weeping for a while. Letting them weep won't hurt anything, but is a little messy. I recently installed new ones, and it is about a half a days job, if you take the time to decoke your heads and pistons, etc.

You can shorten the job by only removing the cylinder far enough to replace the seals. This way you don't have to mess with the piston rings and stuff.

Sean Kelly 29 Mar 2001 13:58

Thanks for the advice guys.

Although I'm not particularly experienced with engine work, I think I'll replace the seals myself before I set off. No real point starting with a leak! And, at least then I'll know what it looks like inside.

Good ideas about leaving the pistons in the barrel.



------------------
Sean

maxpowers410 25 Jun 2014 15:58

Hi Sean

Did you ever get round to changing them? have the same issue.

cheers


All times are GMT +1. The time now is 07:53.


vB.Sponsors