Start by adjusting your throttle cable on the handlebar side. Adjust so there is just a hint of movement in the throttle before rpms rise. You can look through your diagnostic pages to D01 to check your throttle position.
Check your throttle cable routing as well. Make sure nothing is pulling on it, and also make sure nothing is squeezing or pinching it. Check at all handlebar turn angles.I have a 2011 Grizzly 700 and the idle remains high when I let go of the throttle. Early on when the problem 1st appeared I could goose the and get it to step back down. T can not shift the gear shift lever while the revs at high so I turn the engine off to shift. Where do I start to look for this hang up?
Check your throttle cable routing as well. Make sure nothing is pulling on it, and also make sure nothing is squeezing or pinching it. Check at all handlebar turn angles.
A sticky throttle can get you in trouble fast. It is best to make absolutely sure there are no problems.
I have a brand new thumb throttle assembly off a 2011 450. No 4wd switch on it though cause I kept that. PM me if interested, I'll sell it cheap. Just need to verify it will fit. I know it isn't exact same assembly part number, but pretty sure it would still work. But I will verify.Finally figure out the problem after a long time without out any issues. The point where the throttle lever assembly and cable connect is broken. How difficult a job is it to replace the assembly and the throttle cable? Any special tools of tricks to get this done? This bike has never been into a Yamaha shop yet so I have no idea the labor cost. Parts are approx $170 at babbitts