fuel to air ratio sensor troubles

I dont know If anyone can help noticed mostly street bikes but I did some hp mods to my sons 2006 Yahamma Blaster I installed a Toomey R1 race exhaust kit  a boost bottle rejetted carb. Jet kit came with

Exhaust System added highflow airbox and filter And a motion Pro twist throtle. Now here begins the problem

in the kit you use the stock carb. you just replace jet and needle but you must  unhook the F&A sensor  and use a plug with a jumper wire to plug in its place It runs great for a while but then it will start to idle out of control way,way to high It cant even be ajusted by idle screw . the only thing that i found to stop it is put it on

1/2 choke but then you must keep it reving or it will die. The throdle is working fine not stickin choke is openning and closein' fully the only thing I can think it could be is something to do with this  F&A sensor

have called toomey but give me the run around  on how all there kits are dino tested and work.

I have lots of exp. with dirtbikes & 4 wheelers  Working on them & racing them But this problem

has got me pulling my hair out  has anyone had this problem or know anything I maybe over looking

Have been doin' this along time since I was 13 now in mid 30's but not to old to learn

have take it to a shop cost me 75 bucks to tell me they cant figure it out any help would be much appractied

I think it sounds like an a/f problem like you mention.  It sounds like the bike starts up in open loop and runs fine, then when it switches to closed loop it's either dumping fuel or cutting fuel because the a/f feedback isn't correct.

I would try plugging the sensor back in and seeing if it will idle correclty that way - at idle your mods shouldn't make a huge difference in the breathing ability of the bike.  If the problem goes away you can try to get a replacement "jumper" or get the bike retuned for the mods so that the a/f sensor will still function (if that is possible with that bike).  If you continue to have a problem I would doublecheck all exhaust flanges for leaks (however this won't explain why it runs great at first and then starts to idle high).

Yes I do run a k&N air filter but I use a Filter lube called SX because of the issues you describe.

Yes I have tried this but the bike will not start with out it being plugged in and if you unplug while it is running

It kills the engine.

No I should have explaned it better Sorry, The sensor is not even on bike anymore the sensor was in the top of the carb. This was removed when the motion pro twist style throtlle was removed. If the plug that is in the factory setup is not  plugged with the jumper wire it will not start nor will it cont. to run if running. It must have some kind of engine protection function I was wanting to know if anyone knew how to get around this

I am along time KTM fan I still have a 1992 KTM SX  But my son likes Yahammah