change the rear trans drive pulley too a 1200 item it will be 2 teeth larger,   what year model bike

by changing the engine sprocket  you will lose torque & quick rev

Leave it, A 883 with a 1200 kit will always beat a factory 1200 of the line because of the smaller front pulley. a lot of guy with 1200's fit the 883 Gear to their Bikes just for that resion

if you go out into the country better off changing the ratio trans drive pulley,  it's depends what speed you sit on

I've left the pully on my 883 to 1200 conversion, loads of fun. It's only 450 rpm anyway, not going to do any damage to the motor. Will only use a mouthful of extra fuel.

Hi i just want to ask a question following on from this, I am wanting to fit a drive sprocket from an 883 to my 1200 sportster 48.
what can be done to recalibrate the speedo after i've changed the final drive ratio ?
I have the HD 70900274 digital / RPM combo cluster fitted and also own the SEPST dongle, software and lead.
I don't know if any of that will help me change the pulse count on the VSS to get the speedo reading correctly ?
Can this be done ?

I have seen a part S&S make that lets you adjust your speedo after a ratio change it's in there S&S cat.