Inlet Timing

[sean brady scooters]

another thing to consider on this thread is the crankshafts themselves ,and how they are actually modified !
the mazz cranks for eg are just "slashed back " and yes in theory they do extend the inlet timing (by extending the closing time) but because of their shape they are still very restrictive .
what i mean is ,no matter what the port size is or the inlet timing is .. the inlet charge still has to negotiate its flow around the crank, and the better its shape (the less its restriction is in fact ) the better it will be .
just compare the new pinasco cranks to a mazz one ,a world of difference there in shape and flow .