Predator 420 won’t run!

[Davidroberts352]

Hey, I am looking for some ideas on what could be wrong with my 420. It back fires through the carb and will fire off intermittently. It started this randomly one day. It is relatively new and not at all abused. I have checked the timing, spark, new carb. Went through all the internal and no luck. I did not take the head off yet but it has compression so I do not think it is a valve issue. Has anyone experienced this?

 

[Joe-405]

It’s one of the following.........

carburetor issue
Broken flywheel key
Cam was installed wrong
Bent valves
Rocker arms are adjusted wrong
Bad coil

 

[OPmini]

Like fire coming through the carb? geez

 

[Denny]

I would check for bad or dirty gas first. Pull the float bowl and check for junk or water in it.