5HP Briggs pops through carb

[Pasta]

Hi guys & gals.
I've been away for a while but got back into my mini bike again recently.
I have a little trouble hopefully someone can help me with. When I pull a hill, or throttle hard from idle, the engine pops through the carb. If I let off the throttle and ease into it, it will run smoothly. It only seems to do this under heavy load, or sudden opening of the throttle. I tried to adjust the carb a bit, but it didn't seem to make much difference.

Any ideas? Thanks in advance.

George Pasta

 

[lawn-boy biker]

5 (or more) possibilities:
Worn plug
Bad intake valve
Ignition Timing (sheared key)
Lean fuel/air mix
Leaking gaskets

 

[Harquebus]

To have a backfire through the intake, the intake valve must be open at the moment the mixture ignites. I'm thinking your intake valve may be sticking open momentarily or closing slowly.

Could be a sheared or even a partially sheared flywheel key.

Does your engine have points and condenser ignition? Maybe your condenser is going out if so equipped.