Pressure inside rocker box R1100GS

[FLASH]

'Lo Peeps
Does anybody know what the normal pressure is inside the rocker cover? (yes, Albert.....when the engine's running... d'oh!)

Thank you muchly

 

[MattW]

'Lo Peeps
Does anybody know what the normal pressure is inside the rocker cover? (yes, Albert.....when the engine's running... d'oh!)

Thank you muchly

You get a kind of pulsing air movement through the rocker box - should there be any constant 'pressure'? - that's what the engine breather is for.

Go on - tell us why you're asking?

 

[FLASH]

Well....... I'd noticed recently that the oil filler cap was vibrating slightly and I had a little oil weeping from the filler cap area after a fast ride. I had a look yesterday and realised that the filler cap "fitting", the bit that push-fits into the rocker box, had been pushed up slightly (or maybe had just worked its way out). Having another rocker cover handy (like you do) I've switched the fittings. Running the engine and gently undoing the cap I naturally encountered the air pulse you mention. It set me thinking however "How much pressure is in there and how much is normal?" Could it in fact become sufficient to push the fitting out of the casting? Voilà!

 

[MattW]

Well....... I'd noticed recently that the oil filler cap was vibrating slightly and I had a little oil weeping from the filler cap area after a fast ride. I had a look yesterday and realised that the filler cap "fitting", the bit that push-fits into the rocker box, had been pushed up slightly (or maybe had just worked its way out). Having another rocker cover handy (like you do) I've switched the fittings. Running the engine and gently undoing the cap I naturally encountered the air pulse you mention. It set me thinking however "How much pressure is in there and how much is normal?" Could it in fact become sufficient to push the fitting out of the casting? Voilà!

Ah - I see.
My guess would be that it was just tired o-rings on the oil filler cap - my '94 1100 started a slight leak from there - a new cap fitting and o-rings fixed it. Sufficient pressure to lift the cap would probably have oil pi**ing out everywhere

Might be worth checking the engine breather I suppose...

 

[DrFarkoff]

Get two filler cap o rings one for the plastic insert in the rocker cover and one for the cap

 

[bowser]

the parts to fix the problem are about 3 quid, thats for the seal that fits inside the rocker box underneath the little plastic ring that the cap locks into and a replacement o ring for the cap as well, simple fitting job and will sort your problem.

 

[FLASH]

Thank you, Good denizens!