A couple of months ago I bought a Service Honda Junior R from one of the members here. Service Honda makes special Honda conversions, among them the "Junior R" which is a CRF250R engine in a CRF150RB frame. I actually wanted the Junior X which is Service Honda's electric start model (CRF250X). I bought a 05 250X motor off eBay along with a wiring harness and some missing electrical components. After installing the engine I had to find locations for the electrical components like relays, rectifier, battery and starter solenoid. That was the toughest part. The rectifier is up under the front number plate but all other components had to be located in the sub frame. A small Lithium battery is in the air box. Brackets I had to fabricate and the wiring harness was stripped and shortened or lengthened to the components locations. After all was done I gave it a test as seen in the video. What amazes me is how quick it started with the untested eBay motor. I don't know how to embed videos on this forum but here's the link.
https://www.youtube.com/watch?v=RSqg8jj2ZZ8
I still have to do some jetting as the Carb is a 40mm not the CRF250x's 37mm. Still.. this thing starts so fast you can hardly release the start button fast enough. I wonder if a battery powering the coil would make the 150RB start as fast ?