2008 m8 Boggs at 6500 rpm

[muffins51]

My buddies 08 m8 with around 3,000 miles just started bogging at about 6,500 rpm and then backfires! We just cleaned the power valves! Just replaced all 4 plugs. Had new primary put on last year! I'm thinking it's either fuel or electrical problem! Anyone have any pointers! I need to check power valves and make sure they are working and that they are adjusted correctly! Anybody have the specs for power valve cable length? Anything is appreciated!

 

[Pilsner]

Check the reeds

 

[MrHankey]

Broke primary spring ?

 

[muffins51]

Do you think the primary spring would make it backfire if it was broken?

 

[CatMan16]

My buddies 08 m8 with around 3,000 miles just started bogging at about 6,500 rpm and then backfires! We just cleaned the power valves! Just replaced all 4 plugs. Had new primary put on last year! I'm thinking it's either fuel or electrical problem! Anyone have any pointers! I need to check power valves and make sure they are working and that they are adjusted correctly! Anybody have the specs for power valve cable length? Anything is appreciated!

I would say it's the power valves not opening. Take the cable off the servo motor and make sure you can pull the valves up all the way. If possible tie the cable off so the valves are open all the time and try riding like that.

 

[mountianguy]

My buddies 08 m8 with around 3,000 miles just started bogging at about 6,500 rpm and then backfires! We just cleaned the power valves! Just replaced all 4 plugs. Had new primary put on last year! I'm thinking it's either fuel or electrical problem! Anyone have any pointers! I need to check power valves and make sure they are working and that they are adjusted correctly! Anybody have the specs for power valve cable length? Anything is appreciated!

It sounds like the power valves are out of adjustment or not working properly. The adjustment for the cable is 1.437in this is for a 2014. They need to be with in 0.020 of each other also.

 

[muffins51]

Thanks everyone for the advice we will keep looking and I'll let you know what we come up with!

 

[muffins51]

Ended up being a bad wiring harness!