Throttle Position Sensor

Is there any way to check the TPS on a 2007 TE250? We are trying get rid of the off idle bog on the bike. It has the JD jetting in the carb and the o-ring mod on the arm we have checked the valves and everything seems to be in spec. Some one suggested the Boysen Quick shot 2 is this a neccesary Mod? I have not seen any one mention this any where in the FI/Carb section. The bike will stall if you snap the throttle open fast. I'm trying to help a friend sort this out he just bought this bike and is getting kind of discouraged with it.

I highly recommend diving into Coffee's accelerator pump thread (it's very thorough and informative) and I'd suggest that before doing any major surgery on the bike you check that your mate's a.p. is squirting properly, as per Coffee's videos - nozzles can block and the (tiny) one way valves can get jammed with dirt.

Finally, if the bike is running good on a static throttle setting then I'd be inclined to say that the TPS is fine. Let us know how it goes.

I doubt the TPS is the issue. (although one thing you can quickly check is that the little tiny connector (#109 on the parts fiche) isn't missing) The TPS wont work without it, and it's easy to lose when the TPS is disconnected.

Is this a JD kit that you guys installed, or are you taking someone else's word for it? If you didn't install it yourselves, verify that the right jetting is actually installed.
Is the entire carb absolutely clean inside?(not just the bowl, but the entire carb, top to bottom, inside & out- every orifice, nook & crannie hospital clean)

There are a few things that this could be;

Dirt in the AP diaphragm (we had a guy in our club that somehow had his completely packed with dirt, god only knows how it got in there)
Partly clogged Pilot
Partly clogged Main
AP not working properly due to a clog or a bad seal somewhere(or as pointed out above).
Is the JD Oring on the AP screw present?
Small leak between carb & motor...

Sometimes there are a combo of issues contributing to the problem.

Update: I found out how to check the TPS in the Manual with a Meter and the TPS checks ok. We also read and checked all the videos and information on the AP squirt duration and found that the AP is functioning ok,although not the way we would like it too, it does not appear to be blocked in any way.There is a #65 leak jet in there now and we have an 35 on order. Yes there is a genuine JD jet kit in the carb. current jetting in the carb is
Red Needle clip in forth pos.
180 Main
Pilot 42
Leak 65
air fuel screw 1.5 out
bike starts up and idles and revs through the whole range and still stumbles and some time stalls when throttle is opened fast. We tried differen't AP screw settings without any differen't results with the O-ring on and off of the linkage. And differen't screw settings also.
The bike may be a little rich on the jetting but still runs good except for the bog and stall condition. We will go all through it again when we get the #35 leak jet. I could not find what the stock jetting was in the manual,they should put all the english and other language sections separate its a pain in the A@#$ lookin through it especially on a computer thats not next to the bike.

I'll pass this info along as I won't be around for a few days to tinker with the bike. Thanks
Bill

Update on my friends 2007 TE250: Changed the leak jet to a 40 and played around with the fuel screw and got it running pretty good, also had a Husky Mech. adjust the float level.We had it on the low side. The manual says to check it on angle but shows the picture with it level???? Thanks to all who advised on this and to Demi for his advice and settings.
Bill