I have a 2007 SLX 250 with an 8.1 L V 8 Mag 496 engine that will not rev above 3500 rpm. It appears to backfire with a loss of power if I open the throttle above this figure ; especially when putting the engine under load. Iv'e spent thousands of Euros trying to cure this problem and I'm now pulling my hair out. A new fuel assembly and HT leads haven't cured the problem . Can anybody give me any advice please. Thank you . J.
