Mikuni main jet questions

[Dumbjer]

I ordered some 112.5 main jets. Is there a performance difference between the"large main jet", and the "small main jet" if they are both 110 or 112.5 etc.?

I have the "large main jets" and they are larger in diameter than the stock ones.

[Dumbjer]

I'm trying to figure out why my bike is acting the way it is. It accelerates awesome, but once I stop accelerating, it feels like it is, for lack of a better term, loading up. The exhaust tone starts getting choppy. If I give more throttle everything smooths out and the exhaust sounds smooth again.

[reelrazor]

"Large" and 'small' literally refer to the physical size of the outer part of the jet....means nothing as far as performance.

I would use the ones that are equal in size to the stock ones(meaning you have the wrong ones in there).

Sounds like you need to continue in your jetting journey.

Look thru the RT CV carb tuning guide-I believe it's in our Wiki section

[~JM~]

I'm trying to figure out why my bike is acting the way it is. It accelerates awesome, but once I stop accelerating, it feels like it is, for lack of a better term, loading up. The exhaust tone starts getting choppy. If I give more throttle everything smooths out and the exhaust sounds smooth again

Well hell... That's easy! Don't stop accelerating. Problem solved.

~JM~

[Dumbjer]

Not exactly sure what was causing the problem, but I put a different set of carburetors on with stock main jets and stock needles. The bike ran great, but I know in need to go up on the mains from 107.5 to either 110 or 112.5's. I have stock air box and a full Vance & Hines Supersport exhaust. Should I do the 112.5? Or only go up to the 110's?

Thanks for your input!

[ragedigital]

I have stock air box and a full Vance & Hines Supersport exhaust. Should I do the 112.5? Or only go up to the 110's?

Thanks for your input!

Yes.

It's called trial and error. This is part of the learning curve. You will learn how your bike responds at different throttle positions over time.

Personally, I would try the 112.5s and see how it responds.