sorry guys for the typo its a 150cc . coolster only made a 150 and a 250 .

You got any pictures of the engine.

the saga continues, did a port and polish on the head today, played with the jets a little ended up at 38 and 140 and still only 36mph thats right the port work lost 2 mph!! this motor has no velocity, every thing i do to free up the intake side, like port work or larger intake and or carb slows it down due to the fact its generating no velocity and it needs the smaller IE restrictive passages to generate velocity, so i put back on the stock carb and still 36mph , for giggles i put back on the stock cdi still 36 mph. so in my experience when you loose power from port work and or larger carbs and or valves ect its often from having way to small of a cam. i can put my buggy in neutral and free rev it and not hit any revlimiter on the stock cdi if it has one, and it revs so lazy i wonder if this thing came with the smallest of the cams offered, it would explain why its only responding to exhaust mods and not intake. im about to go back to my original plan of turboing it and be done with it, its nothing a few pounds of boost cant fix im sure. but this issue is bothering me so i figure i will try a little longer to get it going. if i decide to go with a cam what should i choose if i want to gain gobs of midrange and some top end?

oh and to the guy asking about a pic, no i dont have any on hand, but it looks like any other ching chang gy6 knock off. it even still had the kick starter gears in it for scooter use.

Thanks for the info!!!You can over do a head.Maybe you ought to try a 4 valve head.I got big gains with a 4 valve head.What is your sproket size?

I got a large port head with a 30mm slide and it runs perfect. I think your sliders are holding you back or something. If your looking to gain both ends, which low end is what you want on a short track, you'll need internal work or a 4 valve head. I think your looking for to much out of 13g sliders. Thats 11g rollers.

Whats a good website to get a 4 valve head

I got mine from Tom at sycpower sports.A trusted dealer on here.

How much did it cost?

dont remember,but I remember theyre not cheap.I got mine from him bc I can call him if I have an issue or question.It does take some work and alittle bit of knowledge to put one on.

Toms the man. If he cant walk you through it, then no one can. That man even called me back on mothers day sunday