4-1header

[chris6888]

i have a 4-1 hidle header on the bike the jet sizes that are in there are

150

42.5

270

it also had the pod filters on it but i have gone back to the stock air box does anyone know if these are the right jets

[chef1366]

I know 42.5 is the pilot jet
150 the main jet??
270???

[chris6888]

150 is the jet the needle from the top of the carb goes through and the other jet is the one at the front of the carbs where the air box attaches to.

[chef1366]

I do believe the 270 is a 170 and it is a pilot air jet.
The 42.5 seems right.
I'd start with a 130 Mikuni main jet. The 150 seems fat unless you have a dynojet kit installed.
See if the end of the needle on the slide has a blunt end or a nice sharp tapered end.

[tom203]

150 is the jet the needle from the top of the carb goes through and the other jet is the one at the front of the carbs where the air box attaches to.

Stock main jet would likely have been 110- the pod/4 to1 exhaust would have changed this but 150 seems absurd.