CAN YOU ELECTRIC START THE YZ450F?

Even though the 2003 Yamaha YZ450F cases have the openings to accept an electric starter, it would be prohibitively expense to mount the WR450 starter onto the YZ450F. The associated costs would include a new airbox, new side cases, different ignition, flywheel and gears.

Can you electric start a YZ450F? Yes. But a much cheaper solution would be to buy the new Yamaha WR450, which comes with all the electric start hardware already attached, and turn it into a YZ450. It would be much cheaper in the long run–and not as difficult to do.