30 tooth on 48

Best thing I ever did to my old 48 was put a 28T pulley from an 883 on, really woke it up and got it into the powerband sooner. Highway rpm wasn't ridiculously high either.

Joker machine make a trick looking cover.

CD, go for it! i like lower gearing & much easier on motor. think my m2 Carb Buell has 27tooth front pulley same as sporty just lower. my carb sporty 1200 bit taller but have to check what sprocket . i just did 260k non stop run on sporty this morning and did not hit reseve. the peanut gas tank the best! just for carb very hard to find, mine has the ugly long tank . Buell has lower gearing than my 1200 carb sporty gets good economy 3.7L per 100k riding normal has 94HP on LA cycles dyno

Wondering if the 1200 Sportster custom has the same pulley size as a 48. 

I bought a smaller front sprocket by 1 tooth but the mechanics said there wasn’t enough room on the rear swing arm too tighten the belt.Did you guys have any issues like this 

Have you done the numbers in a calculator?  My gut says that with all things being equal between two bikes a stock geared would thrash the 27 tooth option.  UNLESS the maths have been done to time the finish line with max rpm in the final gear.

I recon the gear changes will kill your speed; unless your clutchless shifting, but thats bloody tricky from 1st to 2nd and not elegant 2nd to 3rd (but doable).

Never hurt to give it a crack!....  Read up on the small sprocket size though as can the belt bend that radius okay plus would you have enough adjustment left in the rear axle adjuster.

So, old school knowledge on what I did on my other bikes might help you a tad bit. Am gonna use the term sprocket because that's all I used instead of fancy pulleys and belts :P

How do you find the powervision, specially the basic auto tune feature it comes with it? Am guessing you are running a wide band sensor with target tune?