Hi
I'm not sure, but probably it will. But it's very easy to check with the wiring diagram.
When you get it, if you need any help let me know.
Probably you can also use one system from ktm from about the same years, they are the same, and it's probably easier to find one used.
You might have to do some modifications to the flywheel, because of the position of the strip metal, that will excite the coil of the pickup sensor ??? Never check.
Haven't checked also, but maybe one flywheel from one SX250F would be even lighter. If you go through the ktm parts number and the 250 has a different ref. from the 450, for sure it will be lighter. Just don't know how stupid your engine will be ??
You know engines needs some inertia from the flywheel to work, for sure you will have a lot less low end torque, your engine will just want to work on higher revs.
I will check parts numbers from ktm and if I find something will let you know.
Cheers
ZAGA