The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Bill Conquest on December 07, 2010, 09:33:44 PM
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I've been finding a bit of oil in the air filter area - a puddle in the corners & wonder how to stop it? Must be from those breather hoses... any solutions? It gets into the carb air tubes..
thanks, bill conquest
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The oil mist coming out of the crankcase breather valve should all go through into the carb inlets if the breather hoses are tight and not leaking. The hose outlets should be centred in the top of the carb inlet ducts to give the best chance of it being carried though into the carbs without puddling.
The purpose of the breather valve is to pump down the crankcase to some degree of vacuum so that as the pistons come down together to BDC on every stroke there is not too much air to compress and be expelled by the valve. Correct operation will be compromised by any air leaks into the crankcase so that an excessive amount of oil might mean a damaged breather valve or excessive crankcase compression caused by piston ring blow-by or a leaking oil filler seal or a dodgy rear main seal letting air in.
Running the oil level half way down the dipstick gives more crankcase volume which helps a little by giving less crankcase compression.
Your 79 will have the old disc type breather if it hasn't already been replaced with the reed type. Might be worth a look to see what state it's in.
You could always plumb it to the outside as Rob Valdez has done
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Thanks, Barry - i'll take a look at that breather valve while I have the case off - just put a new starter in (Euro Motoelectrics are the best!).
bill conquest