Yamaha back firing through carb

[chikin tities]

I recently picked up a rhino 660 with a 686 in it. The prior owner didnt know much about it because he had also had it for very little time. After taking it apart and looking at some of the stuff that has been wrenched on this is what i know.

686 with an aftermarket foam filter, exhaust and a blackrhino cdi.

i have now changed the spark plug, made sure the timing is correct, adjusted valve lash and cleaned the carb.

it start up fine with the choke on and will accelarate with the choke. the moment i take the choke off it idles sometimes and when i accelarate slowly at about quarter throttle it sputters and back fires through the carb. at half throttle its ok then at full throttle it sputters and cuts off and back fires again.

i believe the main is 165 i dont remember what the pilot is, or what position the needle clip is in.

any input or help is greatly appreciated.

 

[BrianReno]

First question, was it doing this before you did any of the work mentioned above?

 

[chikin tities]

i got it with the problems and mods already on it. guy i got it from said no that it ran fine before... of course i didnt take his word on it and i got a good deal for it. so now its my problem.

 

[chikin tities]

i checked all the stuff and did the timing and valve adjustment yesterday.

 

[Craig]

You said foam filter, but what kind of intake tube is on it? is it the stock box or aftermarket?

 

[chikin tities]

aftermarket no airbox.

 

[chikin tities]

just checked the spark plug and its black

 

[facteryfmf]

Check for holes in intake rubber

 

[DUNE DUMMY 29]

DUMB QUESTION. DID YOU CHANGE THE FUEL FILTER?

 

[warlock]

If I remember back in the day they had issues with the fuel pumps. to.

 

[chikin tities]

Fixed it. Bad air fuel screw setup . Thanks for the input everybody.