I have a 1999 kawaski four-wheeler that back fires when i release the throttle sometimes. why is this? it is a

Question

this happens when i slow down.

Answer 1

Back firing is due to a lean fuel mixture when decelerating. Kawasaki 750 vulcans do this.
The cure was to richen up the idle circuit on the carb (turn the pilot screw out, between 1/2 and 1 turn).
The pilot screw is on the bottom of the carb. If you can't get to it with a small screw driver - loosen the clamps holding the carb to the intake and air box manifolds.
Spin the carb until you can see the screw.

Answer 2

Most probably this is caused by 'false' air entering the cylinder. Check the connection of your exhaust studs and the cylinder; they must be airtight. Use new gaskets or rings if necessary, or maybe just tighten a bit.

This will help solving your problem. If not, there is always a chance, your ignition timing is failing. It can be set too late. But since this is a rather new bike with electronic ignition, the false air is the first thing to look for.

Good luck!

Answer 3

Backfires through the intake, or exhaust? Is the exhaust system stock and in good shape? Backfire in the exhaust is sometimes caused by cold air being sucked into the exhaust as you get off the throttle. If you are backfiring into the intake, that could be a timing related issue. I assume this is a four stroke fuel injected. If so, it may be something as simple as a sensor. You need to determine where the backfire is, intake or exhaust. A bad fitting, loose or damaged exhaust is where I would look.

Answer 4

It is running lean.

Answer 5

check your carb