1972 backfiring and smokey exhaust

[mars_ona]

so--

I just got this bike that had been siting for a couple years. So far I have cleaned the carburetors, on which i replaced the float gasket, filled the tank with new gas and also got a new battery & spark plugs. The bike is starting and idles well after an adjustment but is backfiring when i accelerate and sometimes when I decelerate. It came with a 2 to 1 exhaust on it that seems to have a leak because on both sides white smoke is coming out. Im new to motorcycle mechanics and am not sure what to check or where to go with this information...

Also, it has small gasoline leaks intermittently.. Not sure how or why that is happening.

 

[fredintoon]

Hi mars and welcome,
details please. What year and model, (presumably an XS650) do you have?
You could put that detail in a signature line so we don't have to keep asking.
Backfire on acceleration is usually an intermittent spark failure.
Backfire on decel is usually lean mixture/blocked slow running jet/intake air leak.
Where is the white smoke coming from? If you've a 2into1 exhaust it's all coming out the same hole?
And engines can't leak gas. Even if gas is dripping off the engine it must have leaked from the tank, carbs or fuel line.

 

[mars_ona]

It's a 1972 XS2, I'll put that in soon, thanks.

It's leaking white smoke from the two manifolds, and had some black smoke coming from the exhaust itself, which went away when I leaned the mixture. It's now at a 3/4 turn. The backfire happens most when I open the throttle to 2500 rpm in neutral but I haven't tried riding it around and seeing what happens then. The plugs came out light tan when I checked them after I let it idle for about five minutes.

I couldn't find anywhere that the gas was leaking from around the carbs and fuel lines but I'll keep checking that and the tank, thanks