Originally Posted by DRBS
1 13mm from bottom ring 7/32" two then continue to drill two holes then two more below them stopping 3mm from bottom of piston so in all 6 holes you also need to make room in intake port for the top reed to work. you need to take off a little bit about 1mm. they really do make a difference while going up hill or against the wind. check this page out there is a lot of good info here I did change the hole pattern to two by two seems to work better I know I went through 3 pistons to get it right!!! http://www.dragonfly75.com/motorbike...ill-piston.jpg
Thank you for taking the time to share this, its always great to learn new things and Im sure there are those who will see this in the future and it may help them get a reed setup working for them, Ive never ran reeds in the chine girl engine's, but its something I have been interested in.