studdering when outside temp is hot??

[xb1339s]

i have an 04 xb12s, race ecu, jardine, open airbox kit. i bought this bike in 2010 with 384 miles on it, ive never had any issue with it up until this year when i hit the 30,000 mile mark,
when i riding to work (2pm)(80-90-100*f outside temps) after about 15 miles the bike starts to studder around 3500-4000 rpm's, if i lay into the throttle, itll go away after 5000 rpm and go to redline with out issue, but when i leave work at 1 am i have no issues with it, i had a CEL that said 13, O2 sensor, which i replaced and didnt fix the problem. ive put in 2 sets of plugs, and no change, kinda at a loss,

[JMacXB12]

I am having the same problem with my '06 xb12ss after around 20 miles of highway riding, expect sometimes my engine studders to a halt. I also have an open air box kit. I'm beginning to wonder if that has screwed with something...and my bike only has 10k on it. I'm in the same boat.

[newyorkbuell]

Time for a custom tune my men.

[xb1339s]

ive ridden my bike 33,000 miles with this setup, its not the tune

[jimijeans]

When is the last time you Reset the TPS? Throttle position Sensor reset lasts longer on the Delphi 2/system than the newer bikes /2008 through 2010 Delphi 3/system. The Newer bikes have a simple Key Turn Method.
The older bikes need a computer and some ECM SPY software. Many of the Bikes get some sort of Studder when some miles have been logged on the Engine. Seems each one is a little different on the miles area. Check your Intake for some Buildup around the Throttle Body and Butterfly.
Most likely the studder has not set a Historic or Currant Code.ECM SPY will let you check for that with a Data log. Check the small stuff like Coil wires. The Injectors could be stsrting to clog so a little Seafoam won't hurt to run through it. Just follow the bottle instructions and you should get at least 1/4 of the bottle per fill up.
Small Things First.!!
Mine developed the Slight Studder at 22,000/miles at the near same Rpms. I just ride through it cause it has not set a code & does not do it all the time. Mine is an 08/XB12R the 09/Race Bike is never a problem, never been on the Street for a Regular ride.
You could check the Internal Air Temperature inside the air Box housing .
I doubt it is that. ECM SPY is pretty good but most likely you will need to go for a Data Log Ride about 30 minutes so you can study the information where the Studder is concerned.
It may be that the Timing needs to be adjusted just a [Slight bit] to Compensate for Wear.The Data log is a good way to see what is going on .So that way you can determine what the Engine is doing at that Rpm. *Jimi