Theres a big difference between what was allowed for a GP125 and what is currently allowed for KZ. I think its misleading to follow the peak HP numbers too much. Thats without even talking about the difference between a kart and motorcycle application
KZ restrictions….. (numbers may not be 100% accurate)
Exhaust port timing 190Deg max
Venturi size 30mm max
Inlet type reed only
Head volume cannot be under 11.5cc
Analogic ignition only (so no CDI and no programmable curves),
A driveable 50HP under these conditions seems optimistic to me, regardless of who claims it. The 53HP quote from Jan Thiel I’ve been trying to find the source for because its without context about what configuration was and under what circumstances. I would hazard a guess that this motor may not fair to great on a kart, but I could be wrong.
If Riley thinks 55HP is possible then I have some faith, but I can’t see it being done with existing KZ specs. 125open now that’s another matter.