by Fabricater » Sat Jan 26, 2013 7:32 pm
Well, You got me thinking Ron... But now, I'm totally confused. I thought, that the intake charge always led the pin. Generally from my experience, the centerline of the crank pin follows the centerline of the port by 20 some odd degrees. By my thinking (could be dangerous) Viewed from the rear... most two strokes intake port opens at 135 degree's of crank and closes at 20 some odd degrees after top dead center.The longer the stroke... the longer the intake charge duration. (wider the port slot in crank)
Again, as viewed from the rear, seems to me... rotating the front casing on an engine CW would tend to align the port timing to make for a reverse running HB61.
With rear intaked engines.. seems the same principle would work as well.
However, great care is needed to ascertain the proper piston skirt to backplate clearance. Sometimes you can cut a radius in the skirt... but it is always best to create the clearance on the backplate if enough stock is present to do so, although the increased crankcase volume created... is a power killer. ie the charge tends to loose it's velocity, making for fuel/air separation. Nothing that some well placed JB weld in the old clearance cut, couldn't fix.
Where do I have it wrong?
Thanks for your time,
Duke