OK I put in a Biggun rev box last week and the quad started to give someback fires. Some at steady throttle at about 3000 RPM and some that would kill the motor with light acceleration from a start. It would also throw about and 8 inch blue flame out the pipe. While this looks cool I figued it means that exhaust vales are open during ignition or there is alot of unburnt fuel being dumped out? I put the factor box back on and no more flames but a miss every now and then.
I have a Dyno jet kit with a 185 jet installed, K&N and a FMF slipon pipe.
Do I need a jet adjustment, valve adjustment? Need some advise here. My new $130 part is lying in a box!

 

I would have to say that your main problem is the cdi since it isn't really doing it anymore, but take a look at your plugs and see what color the electrode is and let me know what color it is so I know how it is running...I am runiing a 185 and I have an open airbox so I would have to say that your are running a little rich, but will find otu when you look at the plug...Did you change the settings on the adjustment screw at all or change your pilot jet because you will need that at lower rpms where you are having problems...I think it is a mix of problems consiting of your jetting and the cdi you just took off.

 

What you stated is uasally when you put a new pipe on \, and its a lean condition, but as you wrote it stopped soon as you placed the stock CDI on, call Big GUN let em know, some electrical parts fail, also CHECK YOUR GROUND!!!!!clean it retighten the bolt, the CDI's are touchie when they have bad grounds.

 

You think that's bad. . . Now this is shootin' flames out the tail-pipe!!!

 

check the fuse on the throttle side