poping under load

[rigid1]

I have a 2000 pitbull with a S&S 117 cdi engine, S&S Super G carb, runs fine when you baby it. when u run the rpms it is poping and blowing flames out of the front cyl. help im lost, i do most of my own work, checked the acc pump ok back cyl fine changed plugs no help.

 

[X-ray Doc]

It sounds like you are either out of time, running on one cylinder, or a loose connection to the coil or ign. switch. First I would pull both plugs and confirm both are firing, then check the timing. Also be sure all the connections to the coil are tight.

 

[BigDogBro1]

A 2000 Pitbull 117cu.in. ?

How about a 107cu.in.

Did you recently make any changes to the engine?

A few things mentioned above plus more:
Intake manifold air leak
Exhaust gasket leak
Timing
Coil...connections
Plug wire
Plug

 

[05 old dog]

x2 on the air leak....

 

[rigid1]

thanks for the feed back, it is a 117cdi, i ordered it from S&S, runs sweet think i found problem battery ground post was broken,