I have an 01 f4i with about 13k miles on it. Well in first fear when I start to drive its always doggy till I get up to about 3k rpm then it speeds up quick. I've had the bike since march and put about 5k miles on it. It never used to do this before. If won't even do a burnout anymore. Besides that first gear everything else is fine. Some people told me its like that because I stretched it but i had it stretched since I first got it and it just started having this issue. If anyone could give me their input and advice it would be much appreciated thanks

 

have you done any other work to the bike? typically a bad clutch will be most obvious in it's final gear. i'd start by looking at the fuel pressure regulator, assuming the "FI" light isn't blinking at you.

 

If the spark plugs have been replaced already since you have had the machine and the coil packs aren't dammaged i would imagine the following.

If you have an aftermarket exhaust and air filter without the proper tune and power commander bikes lose power.

A map sensor and a tps will both effect low end performance most noticeable in first gear but these bikes are notorious for losing fuel pressure regulators as another member mentioned. Doggy low end.. I smell a map issue, just replace the vacuum line to it for the cost if you look at it, its only a dollar and rather than look put a new piece of hose on it. Has your red FI light blinked at you? Have you checked for codes?