Exhaust will make no difference except to make it louder. Imo the open filter and bigget jet makes little difference either, apart from agaim making it louder. They may offer very slight gains but any increase in performance is very very slight on a 4t 50cc, imo. Still i run both a Leo Vince exhaust and a k&n style filter with a 92 main jet, mainly because i prefer the look of it over stock.
Lighter rollers will help uphill and take off speed, especially is coupled with a stiffer torque spring and stiffer clutch springs. I use 5.1g rollers, race variator, with a shortened boss (36.8mm instead of stock 38mm), 1500rpm torque and 1500rpm clutch springs, with the Leo and K&N filter, dont think i can improve my accelleration and more tbh. I get a decent take off and what i think is good accelleration to 40mph. Tops out around 43-44mph on flats, hits 50mph downhills/slopes. Using 5.5g rollers i get slightly slower accelleration but gain around 2-4mph on flats, normally 45-48mph.
Hills will always be the problem for these scoots cos they have poor torque but on my set up i rarely, if ever drop under 30mph uphill where before as stock i would drop to 20-23mph on some.
Yeah rollers are def 16x13, buy decent ones tho, especially if going lighter and tuning cos the faster rpms will wear them a lot quicker.
