I have a Dax Titan XC50 kit. I have logged about 300 miles and am approaching the end of the break-in period. Though things seem smooth, I feel that my top speed is now around 25 mph or less. I was at around 30 mph. What can be done to bring the speed back up? I have noticed of late also that there is no difference in speed or RPM as I continue to turn the throttle from about 80% full throttle to 100% throttle. I have verified that I have full range at my carburator.