Window in rear of piston?

Joined
Jan 29, 2000
Messages
203
Likes
0
#1
Yesterday at work my boss was telling me he had a '95 KDX 200 with a 220 kit in it. It was put together by a local tuner in Ohio. He said it ran great. After riding it awhile the tuner had him tear it back down then he cut a small "window" in the back of the piston skirt, I think he said it was about 1/4" high by 5/8" wide. He said the difference in the  bottom  end was amazing, making it like a four stroke, but still just as fast through the gears. He highly recommended it. Anyone else hear of this or try it? :think:
 

jaguar

Subscriber
Joined
Jul 29, 2000
Messages
1,450
Likes
76
Location
South America
#2
I recently installed a Wiseco ProLite piston and it has a big intake window in it. Low end power is better too but I don't know how much the window contributes to that since the new piston/cylinder clearance is .06mm and the old was .10mm.(more play means more loss of low end power)