2 Many, remember what time of year it's getting to be. I have already had to jet down every bike at the house to run at the peak. Also, now that your ported and have a lot of power, heat and power go hand and hand. Make sure the motor is not overheating and shutting down. The 300's had a nifty cooling fan that ran when the motor was running and blew back on the cylinder. Might be a thought if that's the problem. Other than that others have given my other thoughts,Bubba