I have a 2001 YZ426 engine in a roadracing (Tigcraft) frame. It's been bored, stroked, hot cams, ported. My problem is the engine cuts out horribly in 5th. But 5th only. The cutting out seems in no way related to rpm. It cuts out instantly when I shift into fifth and will cut out no matter the rpm. It does not cut out in any other gear. I've disconnected the neutral switch and the other wires with it, I put in a new stator, checked all the wiring and connections; the carb seems fine except I have to use a 135 main jet. (I tried re-jetting from 135 to 165 but nothing helps the 5th gear problem.)
I don't see how since I diconnected the wire at the neutral switch, but could it be the CDI?
Any knowledge, insight, hunches, best guesses would be greatly appreciated.
I'm leaving for the track early Friday morning, Aug. 19, so I won't be able to respond until Monday, but thanks in advance for any help.