Smoking coming from engine?

[TheNewGuy]

I would do a goooood cleaning on the carbs before pulling the head. I wouldn't worry about the compression numbers until you have the bike running better.

Just my 2 cents.

Just got the carbs all dipped and going to reassemble to see how it goes. Will report back tonight

[bassace75]

I have a similar issue. Oil leaking from where the tach cable connects to the engine. The oil leaks down the curve of the cable and drops onto the top of the exhaust. When you start it, there is some smoke produced that comes up by the tank. I thought it was a valve cover gasket leak or an exhaust leak until I discovered the true source. Also, while riding, the oil is blown around the fins to the left side of the engine and will spot my lower pant leg if I fail to clean the oil first. I have a gasket to replace to stop the leak as time permits.

[49er]

Hey guys, white smoke/vapour in the top end area on the GS750/850 engines, is usually a sign that the airbox breather slot, directly below the breather tube has blocked. This slot runs across the top of the airbox, is extremely narrow and eventually fills up with rust. Difficult to clean out, but digging into it with a piece of 1.6mm welding wire will do the trick.

When this breather is blocked, the engine pressurises and causes leaks to the speedo cable, tacho drive, chain tensioner and clutch lever areas. This white vapour is atomised oil being forced out.

Now, your low cylinder pressures won't have been helped by crankcase pressure either.

Hope this helps and that you haven't dug too deeply into your engine, just yet!