The engine modification was very extreme, the power output increase more than 150%, even bigger in 130cc engine. While the crankcase and crankshaft remain as stock, the engine lifetime decrease by enormous number. In average the entire engine assembly lifetime was just approx. 7-hours at maximum, the top-end parts was much shorter. As an example please see the cylinder head pics below :
Modified engine capable to rev up to 14,300 rpm during qualification practice or Superpole race. Cylinder liner is cast-iron, with just an air-cooled cooling system this condition actually 'beyond the limit'. Yes, this is a hard-core racing. That is the reason why we must always have the best oil company as our colleague....don't you want to see the chequered flag?
STOCK CYLINDER HEAD ROLLER-ROCKER ARMS ARRANGEMENT
BIG -VALVES HI-COMP PISTON