Yamaha R1 2003 missfire at low revs sometimes cuts out run ok at 4000 rpm

SOURCE: Yamaha TW 200 cuts out at high rpm

I have a tw200 and when I have this problem its from the cam chain slipping back a notch when I unload it from my truck. I leave it in gear so when I let off the cluch it acts as a brake. I ride by my self so thats why I load it that way. I am guessing you load and unload your tw the same way. So remove the timing cover and make sure you are tdc on both the upper and lower timing marks. The bike will run if the timming is off a bit. It's really easy to set the timing on these bikes. It's easier to look for how to on the xt 200 if you need more help.

SOURCE: yamaha 2001 r1

id check the exup valve first! Clean and lube it up with copper grease or the like. if your lucky thats all it is if not the gears inside the servo motor are stripped but just changing the servo motor could strip the internal gears if the exup valve is still seized