Why does Yamaha Golf Cart Backfire

SOURCE: engine backfire

try pulling the choke out a little and see if that doesn't help.  If it does that is a sign that you are running too lean and need the jets in the carb increased or just the air mixture screw adjusted.  If the coke test doesn't help, please tell me more about how and when it acts up. Like after the motor is warmed up does the backfiring quit?

SOURCE: 91 yamaha fzr engine turns but wont start

the floats in the carb are stuck. you can try lightly tapping on the carb with a screwdriver that should do the trick.

SOURCE: have problems starting yamaha xvs 1100 dragstar

Hi there fellow XVS dragstar owner!

I had the same problem before. It is usually caused by the wrong jets installed. have it Replaced with the standard jets that came with it... this will solve the problem on acceleration. Make sure the fuel and air mixture knob is set to 2.5 turns-out from full close. clean the spark plugs.. better, replace it with a new one to ensure clean burning of fuel. also, use unleaded gas. this burns better.

hope this helps
-levibit-

SOURCE: Backfire after shutoff

With the key off and the engine "running down", the idle circuit fuel is still going to into each cylinder then out the exhaust. A hot spot in the exhaust can ignite the unburned fuel creating an explosion, ( backfire ). Let the engine run down to an idle THEN turn the key off.

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SOURCE: Backfire

is it a straight thru exhaust, or is it just a head pipe with nothing attached? If it's just a head pipe, you need to get some sort of muffler on it or you'll burn your valves out from a lean condition. The backfire is due to the vaccum fed carbs that yamaha runs. They work wonderfully, but under heavy deceleration, the vaccum still feeds the bowl, and it builds up excess fuel, which eventually burns off as a backfire. If it were fuel injected, you could have the fuel map adjusted to lean it out under deceleration.