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Oil filler cap

Posted: Mon Jun 04, 2018 9:59 am
by stevesilver
As bike not sold yet, I'm prepping it for annual pilgrimage to Assen next month.

I had a very minor weep from filler cap when motorway cruising. As it doesnt happen any other time I guess it's because of constant pressure from within the engine at 5000 rpm or there abouts. It doesnt do it if no motorways involved.

I replaced all the parts last year, it still did it, have just bought the allen key cap, still does it.

Any other things I could do, to avoid setting off with toilet tissue and gaffa tape wrapped around the cylinder head?

Re: Oil filler cap

Posted: Mon Jun 04, 2018 11:26 am
by Hay Ewe^
I had the same same on my GS
I replaced the Oring on the actual cap but no joy (used a BMW one because of the thickness) and so had to get the plastic insert part that goes in to the valve cover.
Problem solved

you need parts 5 and 6 from this IPC Picture
https://shop.maxbmw.com/fiche/DiagramsM ... d=07242017

Re: Oil filler cap

Posted: Mon Jun 04, 2018 12:04 pm
by stevesilver
Hay Ewe^ wrote:I had the same same on my GS
I replaced the Oring on the actual cap but no joy (used a BMW one because of the thickness) and so had to get the plastic insert part that goes in to the valve cover.
Problem solved

you need parts 5 and 6 from this IPC Picture
https://shop.maxbmw.com/fiche/DiagramsM ... d=07242017



Many thanks for that, replaced all that last year :cry:

Re: Oil filler cap

Posted: Tue Jun 05, 2018 5:09 am
by Jeff Highland
I have read that some people have had success using a slightly thicker than stock o ring on the insert. No personal experience.

Re: Oil filler cap

Posted: Tue Jun 05, 2018 10:40 am
by victorlaszlo
Had that on my old R11S and fixed it by changing the entire oil filler plastic insert with cap. That is, bottom O-ring, plastic insert, cap with O-ring, four parts in all, takes 5 min although the bottom part is tricky to get seated properly but some persuation with a correctly sized socket and rubber mallet made it just fine and all in all the cost was about £5. No weeping anymore.

If this doesn't work check that the breather hose to the airbox isn't blocked as theoretically that could build up pressure in the engine and force the oil out through the cap. If that is the case there's a risk the oil level glass could pop out by the pressure = not good!

Re: Oil filler cap

Posted: Tue Jun 05, 2018 5:41 pm
by stevesilver
victorlaszlo wrote:Had that on my old R11S and fixed it by changing the entire oil filler plastic insert with cap. That is, bottom O-ring, plastic insert, cap with O-ring, four parts in all, takes 5 min although the bottom part is tricky to get seated properly but some persuation with a correctly sized socket and rubber mallet made it just fine and all in all the cost was about £5. No weeping anymore.

If this doesn't work check that the breather hose to the airbox isn't blocked as theoretically that could build up pressure in the engine and force the oil out through the cap. If that is the case there's a risk the oil level glass could pop out by the pressure = not good!


Yep changed that lot last year. this breather pipe, dont laff but where will I find it, and please tell me its a tank off job :dontknow:

Re: Oil filler cap

Posted: Wed Jun 06, 2018 12:13 am
by victorlaszlo
stevesilver wrote:
victorlaszlo wrote:Had that on my old R11S and fixed it by changing the entire oil filler plastic insert with cap. That is, bottom O-ring, plastic insert, cap with O-ring, four parts in all, takes 5 min although the bottom part is tricky to get seated properly but some persuation with a correctly sized socket and rubber mallet made it just fine and all in all the cost was about £5. No weeping anymore.

If this doesn't work check that the breather hose to the airbox isn't blocked as theoretically that could build up pressure in the engine and force the oil out through the cap. If that is the case there's a risk the oil level glass could pop out by the pressure = not good!


It's probably fitted with a kink to the o-ring (lower) as it's difficult to seat properly

Yep changed that lot last year. this breather pipe, dont laff but where will I find it, and please tell me its a tank off job :dontknow: