How to rejet mikuni 45 carb on heritage softtail twin cam 88?

Question

the bike has vance and hines with baffles. i want to run sraight pipes. when i take baffles out it sounds like c**p. what jets do i need?

Answer 1

Carb jetting is not an exact science - it's more trial and error.

Contact me for a carb trouble shooting guide.

It will give you tests to make while riding and explain what needs to be changed/adjusted for optimum running performance.

Answer 2

The jets won't change how it sounds, jets regulate the fuel to ait ratio.

If you run your pipes uncorked inccrease your main jet 2-3 sizes up. For example if there is a 165 in there now try a 175 or 180 and then check the plugs to determine the rich/lean condition.

White plug = lean ,you need a bigger jet

dark plug = rich ,you need a smaller jet

A dusty tan color is the ideal.

additionally you'll have to adjust your pilot s***w for the low end fuel air ratio.

*****But again, jets don't effect the sound.*****

Answer 3

The pilot jet and the secondary jet, you might have to go to a smaller jet needle. I wouln't worry about the main jet, It doesn't come in to play till you get up to 3/4 throttle. Try to find a place you can hold it open for about a mile then pull the clutch in and shut off the engine , float to a stop then check your plugs. They should be tan colored. I had a few Mikunis on HDs, I loved them. You can replace the jets without taking it off the bike.