I've been thinking about attempting this project for years, and seeing as how with my hip arthritis being to the point I can barely swing my leg over the seat of a dirt bike, rather than sell my KX500, why not steal the mint running engine and stuff it into my CRG shifter kart !? Here's a few pics of my CR125 race kart :
The first issue is the drive sprocket. I need a KX500 spline and a 428 pitch sprocket and nobody makes one. So time to get crafty !
I machined an arbor fixture and machined the OD of a standard KX500 sprocket :
Then I bored the ID of a new CR125 kart sprocket (428 pitch) to mate with the KX500 sprocket. I chose an 18T for now as I generally like a 16T with the 125 engine so I should be in the ballpark.
And problem solved ! I now have a custom KX500 428 pitch drive sprocket. Here?s a pic of the sprocket all welded.
So the next phase is the engine mount and exhaust pipe. I currently have some leads on local to me custom exhaust fab shops. I want a clean fitting and functional pipe, and the OEM KX500 pipe simply won't work by design. I'm also going to dig my 500 out of storage this weekend and yank the engine. This project is gonna be INSANE
when i'm done ! I need to do some caculations on gearing and does anyone know what the upper rpm range of a KX500 is ? I'm taking a guess that peak around 7500 rpm's ?