I need some help three weeks ago fouled a plug out on the trail in the middle of the woods had to ride on one cylinder back to the trail head. Occasionally the dead cylinder would back fire {i assume gas is building up and finally exploding. just guessing} Here is my problem went and changed both plugs today started her up and she still wants to backfire on that side from 1/4 to 1/2 throttle then is fine from 1/2 to full throttle. Is not a case of where that side is not firing either revs fine from 1/2 to full. The backfiring noise is not a huge pop or bang, although occasionally it will pop like that but mostly is just a loud PHOOOOOOOOOTTTTT!!!!!!!!!! any help would be appreciated thanks. Last but not least it only happens in first and second gear.

 

Check the carbs or carb..Had a problem like this when I had the swong washer inder one of my main jets.It puts the jet to close to the bottom of the bowl and can't get enough gas.Also check for air leaks on that side(carb boot,cap etc.)that can do the same thing. Most important DO NOT ride it till you get it to stop.Most of the banshees I work on end up with major problems because they originally had a minor prob on one cyl. but with the other one still fireing it can wreak havoc with the internals.

Greg
'98 banshee
'89 LT350xr

 

Backfiring on a two stroke engine means a lean condition. I would first check the compression of both cylinders to see if any damage has been done already and go from there. Check for air leaks and richen up your jetting. I make most of my jetting changes with my needle settings.

 

my friends banshee was the same way. his manifold was ripped from the heavy boost bottle he had on it. he got new manifolds and put the stock tube back on and it runs fine now.