I have a 2001 Yamaha and if wont take hardly any trottle, when you give it trottle it spits and sputters and tries to die, and sometimes it backfires. it starts and ildes perfect. anything that anyone could tell me would be helpful. Aldo how do you adjust the clutch on it?
Thanks

 

Sounds like the parking brake. Your best bet if you haven't done so it to buy a e-brake block off plate. Rockymountainatv.com has the tusk for like 8 bucks + shipping. The tusk block off plate comes with the rubber o-ring needed for the install. To check and see if this is the problem you can unbolt your head lights and take the hood off this take a whole 5 minutes at the most. Follow the e-brake sensor down the steering stem and find the plug it is connected to. Unplug it and see if you can rev it.

 

Yea its your parking brake i took my parking brake wire off.

 

Your bike is running to rich for your elevation. When you give throttle your carb is being flooded with fuel