1979 GS750L Smoke? or Steam coming from airbox when idle.

[Matty_B]

Thanks to cowboyup3371, to directing me down further, I had the blinders on... anywho

So I bought the bike last summer, had trouble getting insurance.

Had the carbs done, and rode it around the block fine.

I found insurance and got it road worthy, and long story short, It broke down on it's maiden voyage and I ended up spending a chunk of change on a mechanic to get it going.

Crossing my fingers now every time I ride it.

Anyway, it seems to be running fine now, as far as I would know, I'm a first year rider. However, when it's hot, and I've been running at 80-100 for a while, when I'm at idle, smoke, or steam comes out of the airbox, where the tube runs from the top of the engine.

Other than that and the ridiculous smell of gas it gives off, I love it haha!! sorry earth, and the people in my mirrors.

Can anyone maybe suggest an aftermarket pipe, that would eliminate some emissions, and also a jet combo that I would have to use...

Right now the main jets are at 97.5, which is low, am I right?

[tkent02]

Probably blowby coming from the breather. It goes out the breather through a hose into the airbox. Is this a higher mileage bike?
Basscliff's big website has everything you need to know, should you decide to put a few weeks into reading all of the information he has compiled.

[koolaid_kid]

Strong smell of fuel, and vapors from the airbox. Sounds like time for a carb rebuild to me.

[Toadstool Food]

Had the carbs done, and rode it around the block fine

Matt, sounds like you have the carbs sorted out. A blow-by problem is worth a compression check. Weak rings can push a lot of fumes out the vent. Also check carefully for fuel leaks, cracked hoses and bad floats. I don't think your exhaust is the source or solution to your problems.

[49er]

Sounds like the vent tract inside the airbox is blocked with rust. They are thin, so it doesn't take much rust for them to become completely blocked. This happened to my 850, which has the same airbox as your 750. I used a piece of welding wire to clear the rust from the vent.

When these vents block, you end up pressurising the crankcase which forces gases past tired old piston rings!

You probably have oil leaks on many parts of the engine as a result of this too.