12600 is really, really low max rpm for a leopard. You would have to lean out your low speed needles to get it to pull off of corners at all with that low an rpm. And since max torque is 10-12k rpm, right end the end of the straightaway just before you’re about to brake you’ll be in that max torque range the engine is suddenly going to take off like a bat outta hell. It will make for very sloppy driving. I think you are much better off revving it to 14,500 or so and just leave your high end needle on the rich side. You will be able to go 20+ hours without even touching the top end this way.
Edit: you could swap on a JR header and carb and really have just about the same performance as the KPV<br>
It looks like there are a couple jr headers, a 25mm and a 30mm. Any idea what the HP difference is between these? Perhaps a better option would be to drop the rear sprocket 5 or 6 teeth and then put a jr header on there.