Engine pitbike 149 YX -big flywheel-

56 mm stroke 60 mm bore
Oil filter model Honda on the clutch cover
Big flywheel magnetic to give more power flexibility
Attention, by starting the engine on the kick do not open the throttle more than 10° to prevent risk of kick-back
 
Using the CDI box 2418 strongly recommended.
 
box CDI microprocessor reference 2418 here