Author Topic: Leaking rocker cover gasket. (Read 3253 times)

banjomandolin · « **on:** January 08, 2007, 12:08:13 AM »

I have recently noticed a smell of cooking from the engine of my Bis after I have been on a journey and parked up. After investigation I have found that the smell is cooking oil. The rocker cover gasket lower length has slipped away and is dangling freely thus allowing oil to drip onto the hot silencer and vapourise. I have removed the rocker cover and found two splits in the gasket. I bought the gasket last May '06 and has only done 700 miles. Can anybody suggest some suitable alternative to seal the joint. I have some liquid gasket goo which comes in a tube but feel the joint needs something with more "pudding".

Pete126 · « **Reply #1 on:** January 08, 2007, 01:05:50 AM »

i sandwich the cork gasket with clear instant gasket. once it sets it holds the gasket in place, make sure the mating surfaces are clean and dry. refitt then just run a cloth round to remove excess.

ChrisRLewis · « **Reply #2 on:** January 08, 2007, 10:00:39 AM »

air cooled or watercooled?
the aircooled motor can have either a cork or rubber rocker cover gasket. Perhaps the rubber version would be better if it's an aircooled?

bis13 · « **Reply #3 on:** January 08, 2007, 04:28:40 PM »

hi what is the gasket made out of? if its cork why not make a thicker one? or buy some thick gasket sheet and make your own? i did this on my bis on various gaskets (but didnt change rocker cover so didnt bother).it could also be that as you tightenned the last one up it slipped and made a crease and so weakenned it resulting in its failure . tighten up the rocker cover progressively and make sure its to the correct torque . use gasket sealer on this as well it doesnt hurt to take the extra measure.

banjomandolin · « **Reply #4 on:** January 08, 2007, 08:20:23 PM »

Thanks for all your replies. The gasket is made of rubber and has split at two positions. The mating surface of the cover has a raised membrane running along the entire length and, on tightening, it seems as though the membrane has pushed through the thickness of the rubber which has caused the splits. I probably over tightened the nuts. I am going to try a new gasket and see what happens.

Chris Lakin · « **Reply #5 on:** January 08, 2007, 11:58:49 PM »

ive only ever used a rubber gasket, but i would image them to be better than cork as they quash better. plus cork does eventualy dissintergrate, (not what you want in your rocker gear and oil)

other thing i was thinking is stretched/damaged threads not holding the rocker cover down properly, but you said the actualy gasket is damaged so would suggest it must be over tightening,

nothing more irritating than a leaky rocker cover, as David Mcneice (126cab) always says alot of oil looks alot.

regards

Chris

126dave · « **Reply #6 on:** January 09, 2007, 06:47:21 AM »

duno how old this thread is........but,if you use a rubber gasket,you should really use some rtv silicone as well,fit it with finger tight nuts,then when ther rtv has cured tighten it,other wise rubber gaskets tend to squeeze out under pressure :cool:

banjomandolin · « **Reply #7 on:** January 10, 2007, 12:05:00 AM »

Hi Dave / Chris, I fitted the new gasket today. Yes it is rubber. I applied some blue gooey silicon type compound out of a tube to the mating surfaces and left it for 5 mins as per instructions then bolted it up and went for a test drive round the block. On return everything looked fine and no more cooking oil. Thanks.
My next task is the volume control / mixture screw. It is very stiff to turn and feels as though the thread is damaged.