Steam Power???

[(RIP) pastyman]

Having read an earlier thread about steam chuffing from the rocker box cover, I thought he must have hexed mine cos I started the old girl yesterday, Havnt been on it since I went up to Proffs about a month ago, and hey presto there she was chuffing away. Now I know these are not water cooled so I decided I had better look a bit closer. (And no I dont use a jet wash. Not often anyway).
I've put some pics on which show what has caused this, not a problem but I would have expected a bit better from BMW. The first pic shows the inside of the rocker cover, In the centre there are three compartments. Middle one for the bolt, the other two.... The trouble is there is nothing tostop water getting in there as gasket sealing surface is proud of the level. Stick a gasket on it and its even worse. see pic 2.
Ive checked Bertha and she is exactly the same though Ive never seen any steam. Last pic shows the gap with the rocker on and a screw driver stuck in th'ole.
Recon in normal use the heat of the engine would cause any water to evaporate. It cant get into the workings so no probs there. Leave it in the rain or wash it off and it could fill up then bubble away as soon as you start her up.

There was'nt that interesting.

 

[Voyager]

That's not what happened to mine.

In fact, you don't have a problem as the rocker gasket isn't supposed to seal the two outer chambers in the rocker cover so water will boil away when the motor gets hot.

Mine was 'chuffing' because crankcase pressure was blowing through the joint where the gasket had bowed inwards - nowt to do with water.

Having said that, I have seen steam rising from the heads when the bike has been wet, but I've never heard steam escaping from that rocker cover cavity.

Something else to watch out for I guess

Bob.