sx250txrz wont run between 1800-2800 rpm

[nagrof]

I cant *****..My engine surges between these rpms.
I have cleaned or replaced all filters I have changed the three fuel pumps,spark plugs,I set the butterflys and tps.I have the service manual
I checked the resistance of the 02 sensor 4 ohms manual says it should be 100 ohms I asked a guy who knows his stuff he told me that wasnt a good test...what do you suggest?This guy is also a boat mechanic.I also cleaned the 02 sensor last year it didnt help it runs great at high rpm,but surges at lower

[boats.net]

It sounds like you need to replace the O2 sensor, Also remove the draw tube that is the the block behind O2 sensor and take it to your Yamaha dealer to see if has the new style draw tube( They were changed in 2000). It probably needs to be replaced also.

[nagrof]

I didnt post enough info mine is an 01 sx250txrz
thanks for your reply,so i assume mine will have the newer tube? Now to mortgage the house and get 02 sensor.

[SHAVRFILLET]

I HAVE THE SAME PROBLEM WITH MY 225 HPDI , I REPLACED THE O2 SENSOR AND THE PROBLEM PERSISTS. GUESS I WILL HAVE TO TRY EVERYTHING ELSE YOU ALREADY DID!!!!