The ”$2000 o-ring”-problem.

The oil pressure on my R80GS basic used to be:

Idle: 4-5 bar
Riding 5-6 bar

Now it is:
Idle 1 bar
Riding 1-3 bar

(Measured at normal temp 80-110° and the same mineral oil)
When the temperature reaches 80°c the engine runs harder and make noises (esp the camchain and maybe the gudgeon pin)
Other than this the bike runs like a dream….


From time to time it also leaks oil through the oilfilter-cover. This might look like the ”$2000 o-ring”-problem described here: http://home.jps.net/%7Esnowbum/Oil.htm

The canister depth is approx 4.5 mm which is far more then the 3mm (tolerance 3.1-3.8mm) in the article. On the other hand HPN says the distance should be 3.0-3.3mm (http://www.hpn.de/deutsch/deutsch.html ) and to use shims(s) if it’s 3.5-3.8.
Well, so I used four shims (which should reduce the distance to 3.3mm) but I couldn’t see any difference on the oil-pressure. I might try to add some more shims….
My canister is of the lipped type and I’m not sure if the use of shims remove leaks 100%.
At next oil-change I will try to move the canister, have anyone tried this?

I have never used shims before (I have had the bike since new) and it looks like the pressure drops a bit more every year.

To increase the pressure I have:
-Changed con-rod bearings (they looked like new)
-Checked oil pump
-Changed the spring in the overpressure-valve (above the timing chain)
-Cleaned the metal-filter in oil-sump (looked clean)

I guess the next thing to check is the main-bearings but that’s a lot of job so if anyone has some ideas please let me know.

Thanks for any input!