Runs but will not get up to speed. When you first give it throttle it will take off fine, at first, then it bogs down to rough idle if not shutoff.

Please see my tips at link below.
Do It Yourself Diagnosis and Repair

Harry, dirty carb or injectors.
Check the attached links,Manuals and guides, Good luck with your Bike
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ATV TROUBLESHOOTING AND MAINTENANCE
ATV Service and Repair Manuals
http://www.carlsalter.com/motorcycle-manuals.asp

the iac sensor is along the side of throttle body , did you give the throttle plate area a good cleaning out this is where the air path is for the IAC sensor , a lot of idle problems have been fixed with a can of throttle body cleaner and few good squirts of the stuff down the hole

I have a ttr 90 that idles well but bogs down at full throttle. Carb is clean and has new pilot and main jets. Seems to run slightly better with intake off. Which leads me to believe the mixture is rich. No adjustment on carb. Stumped?

I’m happy to assist further over the phone at https://www.6ya.com/expert/layne_0fccff498c319c32

your choke Is stuck on the Injector/carborater. when you press the gas It Is lettIng to much aIr In. check the cable on Injectors or If It Is carb get some carb cleaner from your local automotIve retaIler and take the breather off and spray carb. also check around It to kake sure the cable Is.not streatched nor caught.

First check for any cracked pipes leading into the intake manifold If all OK (with no codes showing it probably is OK) try checking the fuel pressure regulator. If you smell fuel from the pressure regulator vacuum side arm (when the vacuum line has been disconnected) it needs to be replaced.

Ok I have r Royobi Tiller (30CC Gas) And last year it ran fine after rebuilding the Carb. This year it was "hard starts" Idles fine, (Tiny whisps of blue smoke in exhaust with correct ratio) Even seems to run better with the choke "on" but still...at idle only. as soon as I touch the throttle...its bogs down in tune with how much gas I give it. Little throttle? Little bog down, Little more throttle? Almost stalls, a normal throttle rev? it stalls dead! Then starts right back up again in 1 pull and idles fine again!? WTF? So after cleaning a clean carb again, (twice) and seeing no change I thought I'd go look at the original diaphragm and compare it with the rebuild kit diaphragm (which is the one in the carb.) And guess what? The replacement has a larger rivet by a factor of "2". So basically it was flooding the carb, I bent the needle tang down, better but no cigar. But I could rev it half way now. A second disassemble to bend it yet a bit further and Vrooom vroom vrooom ****! So check your needle valve even though you think its 100%. (Especially if you rebuilt the carb with a kit!)

IDLE POSITION CENSOR IT IS ON THE OUTSIDE ONTHE SIDE OF YOUR TBI DISCONNECT THE WIRING IF THE IDLE SMOOTHS OUT IT IS YOUR PROBLEM IF YOU LEAVE IT UNPLUGED IT WILL RUN FINE BUT YOU WILL HAVE A CHECK ENGINE LIGHT

Sounds like a timing issue

Even though this is an old post i feel it needs an answer since there is 225 followers wanting an answer. This situation sounds as if this vehicle is either suffering from the Throttle Position Sensor switch which has bad spots in it causing lack of voltage or the Fuel rail pressure regulator which can not keep the fuel pressure built up in the fuel rail making the auto veel like it is running out of fuel.And the transmission speed densor which also controls fuel. The situations for each device has a test that can be done to determine which one it is. And last but not least lets never forget our fuel filter this can cause the exact same problem. I am eliminating the cam sensor because it stabilizes at idle. Eliminating the crank sensor because it too at idle also stabilizes and returns a smooth idle. So a fueling problem is what we have here one of the above. Enjoy and if you need help determining which one just ask me I will help you figure it out. Please rate my advise thanks it is how i receive my achievements.