2010 Summit running rough

[bcbenny]

I have a 2010 Summit 800 with the 163 track.At elevation, over 5,500' the sled runs great at full throttle but if you have to back out of it then it stumbles. If you can hold it at full throttle it will clear and run great again. I have 600 miles on the sled with no problems until the last two rides. I changed the plugs, no difference. I also drained the fuel and refilled with fresh fuel. No change. The motor is stock other than a can.

Does antone have any suggestions as to what I could look at?

Thanks,

Roy

 

[steve2wheeler]

kinda hard to diagnose this one with limited information...

is the sled reaching max. rpm 8200?
is the sled holding max rpm?

I would start by cleaning the rave valves and the carbs.

 

[bcbenny]

Yes, it will reach 8200 and hold it there. It is only on a slope with less than full throttle that I have a problem. Thanks for the rave valve and carb suggestion!

 

[hymark860]

check your reeds. make sure they are sealing when closed