Freestyle Hard backfire

[Nsmith212]

Hey guys, just wondering if anyone has any input. Every time I walk into the garage and start my ski it backfires so hard it almost blows my eardrums out. This has only started after I replaced my battery with a new lithium one and a new jetmaniac coil. It runs great but the hard backfire concerns me. It only happens the first time I hit the starter. I know the msd gives some kind of startup spark or something but that's usually just a little pop and this is like a 357 haha


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[Blue]

When the msd starts to fail this is what happens. You will most likely need to replace it.

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[Nsmith212]

Man what a bummer, it's only a couple months old. But i did have moisture in the ebox which is why I replaced the box and seal and everything. Thanks tho!


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[Blue]

It could also be caused by a failing start stop switch. If u remove the plugs and put the plugs in the boots and try and start it u may notice no spark until u let off the button. If this is the case u can unplug the start stop and jump the wires and if its the same then the msd is bad if its better then it may be the start stop.

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[623pwr]

I went through that last year. I never did figure it out, but i ended wrecking the rod bearing (not sure if it was out of phase or what?)
It could be leaky needle and seats.
Like Blue said, e-box stuff or start stop.

I know I was running reverse jetting and the advent I have has a delay on the spark. I switched to a Blowsion cdi and that didn't have a delay, no backfire. Shortly after that I blew out the rod bearing. Crank works said they could tell i had a leak somewhere and the rod got hot, but my ignition looked good based on the crank.

I had to get my RRP waterbox welded twice it backfired so bad. I hope you get it figured out, but it needs to be addressed for sure.
Most likely a cdi/timing issue, electrical, or some sort of leak.

 

[Pro-pulsion]

My experience has been with electronics. I went through this last year, actually it was a symptom over the last few years...but last year was the breaking point. My ski was always popping a little bit through the exhaust, and when the stock CDI was finally at the end of its life, I was seeing backfire flame fronts coming back up the carburetors. I replaced the CDI, have not had any further backfire/timing/electronic issues since.