anyone use a mzz cut race crank on a polini? is it worth putting one? cheers
A standard crank is open for about 155 degrees of the 360 degree revolution. A heavily modified crank can be open for as much as 200 degrees. If the crank is opened up too much you will allow either the piston to be coming down when the valve is open which will force all the gasoline/air back out the intake (your motor won't run) or in the other direction, the transfers may be open at the same time as the inlet which is also a bad thing. hope this helps cheers mate!
Yea its a must! although i have heard that its not as strong as the stock crank or other more expensive model's but i also dont personally know anyone who has broken or twisted one up. its a little lighter that stock and less rotational mass means more power to the rear tire. i have a 79' p125 w/ the polini 177 and the mazz race cut crank it also stays open a short duration longer which means more fuel. i like mine alot.
Can you say how much intake duration the mazz crank have? I like to cut my own cranks to get the intake duration I'm after depending on how the bike is going to be used. Any idea? Don't like spending that much on a crank that is only a few degrees longer in duration than stock. If I were as rich as you, why wouldn't I. [:)]
thanks micah for the info. actually i already installed few days ago and its a blast alright! im very happy with it. thanks again and cheers!