Motorcycle Repair: carborator, yamaha ttr90, definite problem

Question
My son has a 2003 yamaha TTR90. After start up which is always a chore the bike only stays running if you give it a lot of throttle but then revs real high and races for a few seconds if you try and put the bike into gear since ther is no clutch it just wheelies from under you.

Answer
Hi Matt.

This sounds like there is either a definite problem with the idlespeed and/or carb, the manifold, or possibly a combination of issues mentioned above.

Check the manifold and see if it is loose or cracked.  Then, if nothing is wrong with it, check the carb for loose internal components.  There is also the possibility of a very dirty air filter, so check that as well.

Start with those and let me know what you find.

Good luck and ride safe.
FALCON