The Higher the Jet Number the Bigger the hole init so more fuel goes into engine to make it richer, the smaller = vice versa less fuel means lean running.
some carbs a 120 means 1.20 mm diameter
but on Mikuni it is lm flow (milliliter) flows.
so depends on who makes carb.?
but yah bigger is more fuel
120 main jet on a 28mm carb
if you have a 1979 1982 has an 80mm main jet the carb number is VN22SS i believe. I just snapped mine in half and im looking for one
#56 jets
take off the carb. on the botoom of the carb is a bowl take screwsa out and the big jet in the center is the main jet. remove with a flathead screwdriver
I just bought a size 72 upgrade as recommended. but when i opened up the carb guess what . it had a size 72 as standard. question answered.
buy a jet kit and take the bowl off your carb and and put your jets in
primary jet size 105 secondary jet size 150
IMO, Ratio depends on the carb jetting and oil quality. Try 32:1 (gas:oil) using good synthetic or syn-blend then jet the carb. With stock jetting that should be in the ballpark. Higher altitudes will require leaner jetting (smaller jet size not different gas:oil ratio).
You may have clogged jet in the carb, or in the small fuel filter. Check everything from the tank down to carb, and if necessary take carb apart.
From the factory, the fuel filter would be in the Q-jet carb. You have to disconnect the fuel line at the carb and remove that housing on the carb. Filter is inside.
try cleaning your carb your floats may be stuck or a plugged jet try cleaning your carb with carb cleaner and use a piece of wire to fit through your jets ...
Rochester 2-jet (2gc)