07 m8 backfires high rpm

[bakininthesun]

I have an 07 m8 that backfires above 6500 rpm,this sled runs great below 6500. I have replaced the reeds and have checked the the stator and it is with in spec. This sled is stock except for a can sled did this with stock can also. This sled has 91 non e fuel in it and runs Amsoil. I tried a new o2 sensor from an 07 m1000 and it still did the same thing.

I checked all the wiring and found a few problems that were fixed, still does the same thing. Think i need to look at the flywheel key ? running out of options. Help

 

[Hardass]

Did you check your power valves and cable out

 

[bakininthesun]

Yes, I forgot to add that cleaned and adj the cables

 

[tchriste]

I had the same issue on my 09M8...it turned out to be the spark plug leads....maybe check the leads and plug caps.