Backfires Through Carb

[bw4202006]

Just bought this bike and it is backfiring through the carb but seems to only do it at low rpms. Any ideas?

 

[jasonp]

pilot jet. Fuel screw. Or air jet. LEAN condtion, like pluged jet or someone added a exhaust or airfliter without rejeting. Fuel screw needs adjusting out.
Did it just start to do this or??

 

[yamarider]

Yeah, i'd say it's a lean condition too. The first thing that comes to mind is that it could be a cracked intake manifold, but it could just be a clogged pilot jet or the fuel screw out of adjustment. It doesn't take much at all to get the pilot jet partially clogged.

 

[bw4202006]

I just bought the bike. The Carb Boot was cracked and replaced it and seems to have helped the problem a little bit. It does not die not at an idle when it backfires but it is still there. It does have a DG pipe and dont know if the carb has had any work done to it. Should I get a new jet or should i just adjust the carb?

 

[yamarider]

Try adjusting the few screw, backing it out 1/4 turn at a time and see if anything changes. (the fuel screw is a brass screw on the bottom of the carb)

 

[bw4202006]

I only see one screw on the bottom of the carb and it seems to adjust the idle speed

 

[madcow]

There's a flathead screw on the bottom, near the float bowl cover. It's probably a bit hidden in a metal tube-like thing.