rough idle/miss when cold

[radianguy]

I was just at my buddies place, he was doing the exhaust donuts in his 06 RS Nytro, when he fired it up it sounded like it wasn't firing on all cylinders. He just bought this sled a month ago, said it was like it when he bought it, replaced plugs, had carbs cleaned, replaced donuts, still sounds like he has a small leak, possibly the gasket at the muffler/header joint. When the sled warms up it sounds much smoother, anybody know what would cause this?

 

[dexter]

I was in a similar situation... changed donuts, found crack in mid section of pipe. sounded tighter, but still heard something. one thing lead to another and brought it to the dealer.

had my valves adjusted.... one had a 52% air leak at intake others were in the 30's. yami says 8% or less is acceptable. since adjustment I swear it sounds tighter and quieter. I could be crazy, I am not a mechanic, just a thought for ya. check for cracks in the welds on the pipes.

 

[radianguy]

thanks, I forgot to mention he had to replace one of his flex joints as well. I will mention to him about the valve adjustment.