what size jet would i need to put a air filter on standard

what size jet would i need to put a air filter on a standard gilera runner sp50 carb i have a gianelli exhaust and variator nd would want to put an air filter on my bike without geting a 70cc kit as im only 16 please help and tell me what size id need and how its done thanks

 

don't do it, the standard airbox is just as good.

 

but an air filter would look much nicer though

 

and sound better....just lowers fuel econimy a lil... cmon be fair on the lad anwer the question lol, not 2 hard question is it? i think its about 80, i think standard is about 70...is on mine and a lot of ma mates... dont quote me on that though

 

well my rollers are 4s as the 7s i got with the malossi variator were very heavy if thats any help

 

any help?

 

honestly i wouldn't bother. but if you have set your heart on it, i wouldn't think that you would need to upjet by anymore than 2 or 4 (can possibly set up right on just the needle height)

When the reeds close, there is a small ammount of backwards pressure on a 2t, this pushes mix back through the carb and out into the filter, with an airbox, backpressure is created, terefore charging the mix in, if the airbox is removed then this backpressure won't exist so the fuel will be lost into the atmosphere and the extra little bit of charge going into the engine will be lost, therefore to compensate you need to add a very small ammount of fuel extra to what you had before.