Hello I have these 3 carbs but i don't know which to choose 21 mm it's too big and it uses alot of fuel so it remains the 19 mm one and de 17.5 help me choose thx

whats the setup? for sport/mid race setup i recommendate the 19mm its better then 21 nad 17.5mm carbs

Well i think is mid because i have a stage 6 pro race , polini funky exhaust and a stage 6 crankshaft... oh yes and another question can i make the 19 mm carburator to run with the original filter ?

19mm is the best choise for ur setup.. and yes u can run the 19mm with original filter but also u can try with malossi filter for the original airbox.. or E5 filter

I'll try setting up the original filter for the 19 mm carb ... i tried to set it with the 21 mm one but nothing the engine chokes ...

make a few holes in the airbox

I managed installing the orignal airfilter but i had to drill many holles , i think i'll remain at the polini sport it's runs fine with it