Constant throttle

9 replies to this topic
  • Hypheriox

Posted June 08, 2016 - 01:53 PM


Okay so I have a 2003 wr450. It idles very smooth I just cleaned and rebuilt the carburetor but for some reason if I am driving down the street and I hold the throttle in one spot it gets very jerky. What I mean by that is it almost acts like it loses power and then gained it back. In a sense I cannot stay at a constant RPM without it being jerky

  • AKmud

Posted June 08, 2016 - 02:39 PM


Check your TPS. Voltage should be around .76vdc. Mine smoothed out significantly when I got the TPS set correctly.  My issue was finally cured when I got rid of the cheap plastic nut on the hot start and replaced it with an aluminum nut from ZipTy racing. http://www.ziptyraci.../hot-start-nut/

Edited by AKmud, June 08, 2016 - 02:41 PM.

  • Borgschulze

Posted June 08, 2016 - 04:09 PM


I deleted the ACV on my carb and it fixed it.

  • Krannie McKranface

Posted June 08, 2016 - 04:17 PM


Known issue.


Unplug the TPS to eliminate it, but loose your map transitions.


Calibrate your TPS to a higher resistance, like .8 to 'move' it .


Install a Dynatek ignition to get your mapping back, and eliminate the studder.

  • Hypheriox

Posted June 08, 2016 - 04:18 PM


ok im a bit new to all of this so how would I calibrate the tps?

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  • subxero

Posted June 08, 2016 - 04:37 PM


when i read the thread title i thought you were trying to adopt the Ronnie Mac style of racing. 

  • Krannie McKranface

Posted June 08, 2016 - 04:46 PM


ok im a bit new to all of this so how would I calibrate the tps?


Download the serivce manual from Yamaha's site and follow the TPS calibration instructions, but go to a higher resistance.

You can try mutlipe resistances to find out what you like the best.

  • Hypheriox

Posted June 08, 2016 - 04:47 PM


Ok I have the actual manual so i will look into it

  • WRF-Rowdy

Posted June 09, 2016 - 09:28 AM


Get used to it. BTDT.

  • NovaKid15

Posted June 13, 2016 - 09:54 AM


I just had a similar problem with my wr250f at about 1/4 throttle it would start to almost miss or hesitate. I then took the carb apart cleaned it, tested ignition coil, changed spark plug, disconnected the TPS, checked valves and nothing helped. Eventually I took it to a shop and they put a new AIS removal kit on it, changed the jetting and the miss/ hesitation is gone. They also found that my needle was slightly bent and had been rubbing which may have been the problem.


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