I have a 2006 Sportster 1200 (Carb) and am considering aftermarket pipes for more performance and sound. Maybe the Vance & Hines Straightshots. (I have stock pipes on now.) If I put these on will a rejet be needed? If I choose NOT to rejet, what is the risk? Is it just a performance issue or possibly engine damage?

Thanks.......Ron.

 

You should be alright if you just change the pipes. If you decide to change the air cleaner too, you will have to rejet.

 

dont new sportsters run lean anyway because of the fuel mixture? Will puttin on slipons make it run even leaner?

 

2006 carb Sportster are not jetted lean like the new injected bikes are. I ride a 2004 1200 Sportster and needed a rejet because it was backfiring quite a bit every time I let off the throttle. You're bike may not, give it a try. Rejetting made a hell of a difference in how my bike performed.

 

Ya...they all run on the lean side. Usually rejetting isn't 'necessary' for pipes only. It will lean it slightly, but probably run pretty much like stock.

If it were me, I'd go stage-1 (A/C and pipes) and rejet for a better running bike and about 10-15% increase in power.

 

The problem area is usually idle (because that is where the EPA does their testing), so make sure to pull the cap off of the mixture screw. You should have enough adjustment with that to take care of any deceleration pops and lean issues with the new pipes. Run the pipes for a bit and check your plugs, they'll let you know if you're running too lean.
You can richen up the midrange without rejetting by simply by raising the needle in the air slide if you find that the plugs are showing you running lean.

 

Oh, and yes, running too lean leads to engine damage.