ok people so i decided to rebuild my carb and adjust my valves to get my 01 660 running better - it had been running good at high rpms but sputtering at low rpms, i got a rebuild kit off of xtreme raptor one ways website, rebuilt the carb everything went together good, i tightened the air/fuel screw i think it is all the way down and 3 turns back. thats what my friend told me to put it at. ok and now for the valves, when i got to them and turned the engine to TDC at least i think it was. i lined up the crankshaft and line on the motor but the valves all seemed pretty tight. so i set the intake valves at .125mm and the exhaust valves and .176mm. i put everything back together and went to start it up and at first it started right up and sounded great, it ran for about 20 seconds and then died. after that when i went to start it, it would barely want to turn the engine over - it almost seemed like it was locking up, i was getting ready to pull start it and i decided to try and start it again and it started right up, i ran it around the yard for like 5 to 10 minutes it sounded so much better at low rpms but it seemed like i lost quite a bit of my power i had before i did the valves/carb. after i shut it off it wants to do the same thing it was before and not turn the engine over when i hit the start button. i am wondering if i did the valves too loose/too tight or didnt adjust the carb right. the valves when i had it running almost reminded me of a sewing machine a little louder than they were before i adjusted them. any help would be very appreciated - also ive changed the one way last month so i know its not that. Thanks.