this is weird but i swear its true , i have a 660 and my girl friend has a trx 450r she is an experienced rider and race we were on the ice with our quads, thats when i suggested a hole shot. so off we went now before i go any further he quad is set up pritty nice, white bros full pipe, jetted, k&n, and hot cam stage 1, 12 sproket tooth front and huge uncertified AMA studs now my quad is set up with stock 13 sprocket AMA studs rossier eng. full pipe, k&n, and jetted, all of which i have done my self, however my jetting wrong, like the main jets i thought that the pilot jets were 5 offsett too. so my jetting is 155/160 with my piolets set at 25/27.5. back to the hole shot, her dad droped the flag and off we went. i took her the whole race she wasnt a head of me once. so then her dad got on. he event jumped the start and i still cought him within 2nd gear.
i know what ur thinking LIER. but i swear its true, is it my jetting? i dont know why also i was on dirt and took my friends yfz 450, same thing jetted piped and open air i took him he was in fifth when i was in third and i took him by just about the same length
HOW DID THSIS HAPPEN OVER AND OVER AGAIN?

 

could be anything... rider, tires, gearing

 

If your jetted lean you will get more power but itll eventually blow your motor.