Buell xb12x differences 06-08

Why did pre 08 bikes require a tps reset?

The pre-08 bikes had a less-sophisticated ECM. They had a manually adjusted stop screw on the throttle body to set the idle speed. To set the TPS, you have to completely back off of this idle screw so that the butterfly is completely shut and the zero position of the TPS can be established and the TPS can be reset. You don't have to do this very often, but it's something of a PITA as you have to warm the engine completely, back off of the idle screw, connect a laptop with ECMspy or similar software to your bike, reset the TPS, then manually re-adjust the idle speed.

The 08-up bikes use an Idle Air Control (IAC) valve, which is automatically regulated by the ECM to maintain the idle speed. When you release the throttle, the butterfly completely closes; the IAV "bleeds" air past the butterfly to regulate the engine idle speed. This also means that every time you release the throttle, the butterfly is completely shut and the ECM can automatically reset the TPS.

Pretty cool, eh?

I would go with the 06 with the seat and bags if it has upgrade like driver comfort set up. I had an 06 and after setting it up was a ball to ride. It is very quirky. You will learn more on a Uly than any other bike.

Thanks for explaining that, Im happy I went with an 08 as that tps reset seems like a hassle. I went on my first adv ride this Saturday. I definately need some dual sport tires once the current ones wear out. I found it hard to steer out of ruts. My confidence improved as the miles racked up. I was very comfortable and dropped the bike once when I was stationary. I blame ill fitting pants and not the buell.

On some other boards I read about the motor stumbling. What exactly does that mean?

With the stock tune, it seems most of these bikes have a periodic stumble or hesitation in the 2500-3000 RPM range. You'll be putting along in second gear at steady throttle and ~30 MPH and feel the bike sort of lurch periodically. Apparently this is due to the lean fueling; it's not a big deal.

CORRECT this was hashed out in the buell bliss thread.

Remember folks, there was 2 models. xt and x