My brother has a formula 3 600 that will not get over 5500 rpm, I checked compression 123 124 123 so compression seems fine, installed new/used stator and checked cdi and all coils with good spark on all cylinders, cleaned and sync carbs, new plugs, checked for pto side crank seal leak while running with ether, cleaned and checked rave valves. it seems like one cylinder is kicking out in upper RPMS but seems fine at low rpms. I still need to do a leakdown check but other than that i have no ideas as to what it could be. Plugs are not fouled when I pull them they all look good med brown color. I checked the wiring harness and cannot find any breaks in the insulation. The sled always starts cold in 2-3 pulls and will idle all day just no power. If you hold the sled off the ground and hold it to the bars you are lucky to get 5500-5700 out of it. My brother is 15 years old and this is his first sled, he has had it for over a year now and is getting tired of throwing money at it and it is kind of turning him away from sledding. If anyone has any ideas of something I may have overlooked let me know.Thanks
