It might be a tad more complicated. Often the Ins. Co. will not care much if you keep some parts of the vehicle, as long as it has the overall appearance of being complete, at a glance. I've been told on cars that were totaled, "we don't care what color the body panels are, but it does have to have them all. Likewise as to condition. I scored a pristine hood off a friend's rear end collision car, swapping my trashed hood onto his car. A missing hood, or in this case, wheels, raises red flags.
You might check out a moto salvage place if you can find one locally. Probably several Yamaha's with the same axle dia. Maybe even call some dirt bike shops for some cheap damaged wheels laying around. An undersize axle, (or just a length of thread all from home depot or lowes) and a couple of nuts/washers and you're good.