Hello, I have a super 8 50 2t 2014 model and I recently cracked the cylinder head so I had to get a new top end, I purchased it online and it said it was compatible for my bike.However this piston had a cut out window on it which my old one didn’t. I used to get 39-40 mph now it won’t go any faster than 34-35. Wondering if anyone knows what could’ve caused the decrease in top end speed. Thanks