Smoking head

[maclariz]

Dear all,
Was testing my charging system this morning and running the bike standing for a long time, when I noticed a small amount of smoke (exhaust fumes) rising from under the tank. It seems to be coming from the engine head area. What do you reckon is wrong? Has the head gasket gone west? Could there be another explanation? The bike is a 1978 GS400 and the exhaust ports are nice and tight - no leakage there.

Thanks

[psyguy]

a small oil leak that got to the headers?

[rphillips]

Remember, this is an air cooled engine. The engine is cooled by air flowing thru & around the engine. If you are going to let the bike run while sitting still, be sure to have a good fan blowing on the engine. Probably excessive heat on some oil deposits caused the smoke.

[BassCliff]

Hi Mr. maclariz,

Also check to see if your tach cable is leaking where it connects to the head.


Thank you for your indulgence,

BassCliff

[49er]

Also check that the crankcase breather is venting properly through your airbox. The tract inside the steel airbox rusts up after many years of condensation buildup, eventually causing a complete blockage. When this happens, you also start noticing oil leaks appear around the camchain tensioner, tacho cable and oil pressure sensor/switch.

[windex]

I have the same thing happen on my 82 GS1100EZ. happens after 15 minutes or so. Once I get the clutch back in, I will see if it still does this with a fan blowing on the motor.

[chef1366]

Also check that the crankcase breather is venting properly through your airbox. The tract inside the steel airbox rusts up after many years of condensation buildup, eventually causing a complete blockage. When this happens, you also start noticing oil leaks appear around the camchain tensioner, tacho cable and oil pressure sensor/switch.

That was my first thought. Especially since it's coming from under the tank.