None of us know since only sleds that for sure had tight valves were fixed by dealers and issue was fixed by replacing everything. We who suspect tight valves don't even know that they are yet. It could also just be a coincidence that a crappy tune which was updated this year has the same symptoms of tight valves. I am hoping it's just the tune.
I was thinking about this statement. Not saying you aren't right and am comparing a Dirtbike to a snowmobile. Buddy had CRF450 he could not start it in morning. Adjusted the valves started bike and ran 2hr race. Shut bike off and it then would not start again. Tight valves effect starting much more than anything else.
I have EVO flash and after I ran it, I experience crappy idle when the engine is hot. If I don't put a little throttle in a cold start they would stall if. Sometime I had thinking maybe is because of my mbrp header but seems I have the same valves issue at 8,000 miles
Yea. I will do a cold valve check and go from there. I know I can tune mine decent enough at least with the can on it. The stall thing really bothers me though. It’s almost like a ignition cut off. Idling normal then out like a light. Buddies same thing.
Maybe not valves. What tune did Evo base yours on? There was options. Heck I have even seen issue like that from too tight belt deflection. Have to check everything else before condemning the motor itself.
It's EVO flash 4. I just checked my belt deflection and it is ok. It's seems a little bit worse this year when I started it in a cold day. In the firts minutes I have to put a little throttle. I had never touch it before this year
Similar running issues can have different causes. The first time I had warmup issues we checked out cam chain tension because it seemed likely to be the cause. We continued to try this and that with no luck. The factory sent out a new clutch shaft/coupling with the thought that it was effecting the sensing of the crankshaft position. I checked out the the operation of the idle speed control with the thought that it was not doing its job. Finally in my case tight valves was found to be the root cause. For all those concerned I am hoping that tight valves was caused by the way I drive my but I am starting to think not. More than the way I drive is how much I drive year after year. In my case adjusting the valves to eliminate tight valves immediately got rid of all symptoms on both occurrences. The second time around Lighthouse Motorsports in Rosemount MN figured out a way to adjust the valves with minimal disturbance of the engine. For those that think they have tight valves hopefully they are wrong but if not I would recommend Lighthouse Motorsports.
mis print from me, pic below show correct
