I have a 2004, 1200C Sportster that has a low speed miss/cutout. It happens at part throttle just slightly above idle. For example, when riding in 3rd gear at 30 MPH, there is a distinct random cut out. The miss doesn't seem to be present when I accelerate or at highway speeds. I installed a 45 slow jet and Screaming Eagle Performance aircleaner thinking this might help, but it didn't perform any differently than when it was stock. Any help diagnosing this problem would be greatly appreciated.

 

At 30 MPH you shouldn't be in 3rd gear, you are lugging the motor.

 

what he said ^^

Downshift. It's not meant to be turning that slow quite yet. 35 or so is about the slowest for 3rd.

 

Sportsters like to be wound out. They don't do well lugging.

 

The 45 and air cleaner is the standard to get rid of the small low speed pop that can happen.
Lugging will do the same though.
What pipes do you have? Stock? Might not be the right setup with the jet/cleaner

 

Thanks to all for the great input. Sounds like I'm lugging the engine. I'll try either speeding up or dropping to a lower gear.

I forgot to mention that I am running SE II pipes in addition to the 45 slow jet and SE aircleaner.

Thanks again.

Jerry