Londonoz

I own a K4 and only done approx 2.5k miles with a full Akro titanium on while my mate owns a K3 with about 18k miles stock!.

The issue i have is, my mates bike revs quicker and smoother with a slight flick of the wrist. mine is bubbly and very rough (sometimes stalling) and doesnt get as many revs with the aprroximate same twist of the throttle.

Is this to do with my bike in desperate need of a tune? I would like to upgrage the filter too, what is the best filter recommendation and how much would it cost for the conversion, does this need a tune as well as i remember reading something about that.

Many thanks