Like I said it's not hi compression
Only like 1mm smaller like if you sanded your stock old style head down 1mm
https://www.treatland.tv/Puch-50cc-Hi-compression-head-p/puch-hi-comp-head-50cc.htm
Now this is high compression ^
Almost too much compression. I actually mod the hi hi head for a little less compression .
You just wasted 23.00
30.00 Hi hi head for the win