21mm carbs

just wondered if you have a 95 jet in a 17.5mm and then change the carb to a 21mm to get the same mix would you go higher or lower? i would assume that you would go lower but wanted to check

 

higher !

 

I thought it would be lower :wtf:

 

nah defo higher.

 

He's talking about jets ain't he?

 

yeh

 

So he would go to lets say 100, and not 90?

 

yeah.

 

depends on the carb but usually higher

 

someone also told me bigger carb smaller jet but it didnt make sense can anyone clear it up?

 

depends what carbs tho really
what carb you going from too ?

 

from nothing to nothing lol just wanted to know. just confused me lol

 

on bout alex lol but depends what carb is cause diff carbs jet differently !

 

Maybe this is unrelated. I went from a 21mm Arreche to a 24mm Arreche. I upjetted the main from a 95 to a 105 to get my WOT plug color brown.

My pilot jet is still the same(20). The plug color is good at 1/4-1/8 thottle, but when I roll the throttle quickly it bogs way down.

Do I need to upjet the pilot jet for a bigger carb too?

 

i got a polini dellorto 21mm with the 5mm jets lol im in the process of setting up my rebuilt/tuned new engine so yer just fort id check

 

Can someone explain why larger carbs require larger jets?

From what I gather, a larger bore carb will allow more mixture which means;
more air, which needs more fuel.... Is this correct?