Vintage Dirt Bike Q & A

Hello, I am new to this site and to vintage motocross bikes. I just bought a 1973 Honda CR250 and it is very hard to kickstart as if it has way to much compression. It kicks back so bad you can't start it even with a motocross boot on. It will kick a few times easy and then build up compression and kick back. What is going on with this? Thanks.

Yeah, these kickstarters aren't any help either, especially with an aftermarket pipe bulging out into the way.
Have you retarded your ignition timing to 1.5mm btdc, instead of the 2.2mm original spec. That will lessen the tendancy for the earlier firing at slow kicking speeds to stop the piston dead in it's tracks. You could run a comression test and see if you are getting something crazy high. What are these suppossed to produce, something like 150psi? I forget off hand, but if you have much above that, you might have a base gasket made out of cereal box that's too thin, or shaved cylinder head, year's worth of carbon buildup, or something else that's causing high compression. I expect the timing, and a fully committed kick, and always wearing a boot will help a lot.
Enjoy! Jon

Thank you very much! It was the timing. Starts and runs good now.