So what is the definitive word on TPS? I have searched the forum and found several people say it is unnecessary and to simply unplug it.  Then, there is the crowd that says it will run so much better when properly adjusted. My bike is an '08 WR450 and it has been hard to start (E-start) when warmed up lately and I have to bump the throttle while running the starter to get it to catch. It refuses to start with the E-start when cold, but one swift kick and it will fire right up (brand spankin' new battery...).  I've also been getting a little misfire action in midrange when holding a steady throttle position. Getting on and off the throttle it seems to be smooth with no popping on decel. I'm about ready to pull the carb and clean it to make sure all is well, but I was just in it last fall. It is pretty much bone stock other than the uncorking mods. I'm hesitant to start playing with jetting, but that may be in my future as well.  Any recommendations for jets (0-3000').

Forget the TPS it has nothing to do with your issues. Plugged in it gives you better bottom end. Either you have a tight intake valve or a partial plugged pilot jet. You might through a new spark plug in also.

TPS (on your bike) changes ignition mapping based on throttle position.

The Stock WR ECU has a flaw that causes 'studder' when you are on the cusp of two different maps.

Most noticable on Tarmac at cruising speed/ slight throttle.

Unplugging the TPS drastically reduces the studder, but you loose throttle response, as mentioned.


As mentioned it is not related to your problem.



I ride a 06 wr 450 f with:  Akra pipe +dyno jet stage 2 kit+ air filter box opened + Ais removed.


Off road it runs perfect 

But as you say in tarmac an 85 km/h it does not go smothly.

It feels like the spark fails some of the strokes.

It is annoying.


Could it be the issue with the two maps? 

I have desconected the TPS and the engine stops inmediately.

There is any possibility to install a switch for the TPS, to disconect it only in road?

TPS has 3 cable, Which one should I disconect?


Thanks in advance

Edited by tananita

yes, there have been people who have put a swtich on the tps

I figured out my issue... I replaced the junk plastic nut on the hot start with an aluminum one and it runs great now. The threads on that plastic nut were worn and I had used Teflon tape to get it to tighten down. Evidently the tape didn't work for long and it must have been sucking air past the hot start.

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