Hey guys, We were looking at a couple of cranks. The one Wayne rebuilt with a new shaft does have a slightly larger hole. Looks like this is because of the cutter used to hollow out the valve and end of the crank. Question, Will the larger hole create more suction or less? If it creates more it should run a bit better on fuel transfer. Anyone have an idea which runs better or if there is any difference at all. Bob
Bob ,
The intake path should at least match the venturi size for the carb for optimum intake performance .
Manufacturers have gone by the flow velocity . Smaller carbs with higher velocities are better for engines used mostly at mid range RPM. Engines that are mostly used at high RPM were given larger carbs for lower flow velocities.
Not sure just how Simplex calculated the intake , but , according to 'general' practices , smaller would seem better for our relatively low RPM motors . And , the longer intake path ( from carb mount to crankcase ) should also aid low end performance . RPM gain is a bit slower ( pretty sure that's how it is ) .
Of course , if you're building a race version , LOL , all that^ needs revision .
Pete .
