I installed an 80cc kit on my 49cc 4 stroke dykon. Everything went really well and everything is setup correctly. Valves are adjusted to .004 With timing at TDC. I have a aftermarket high flow air filter On my original carburetor with a # 90 main jet. The scooter runs really well until I go down a long hill. When going down the hill it Feels like it totally runs out of gas in the bowl. it will run perfect then for a Second it acts like it has no gas or no fire and then goes back to running and then does it again and again but only for a second or two and then runs and does it again until I get on level ground then goes back to running fine. I have a jetting kit with a bunch of main jets I have went from #88 all the way to #95 in one # increments. I have also tried taping up the high flow air filter Starting small and going down the length to see if too much air flow was the problem but that didn't help either. Iv run out of ideas. Any help would be greatly appreciated.