Anyone out there have a Ultima 113" motor with a G carb? Looking for jetting advice. Pipe is a short Bassani Roadrage, FXR.

 

In the absence of anyone else chipping in, S&S have tuning guides on their website, which may help you along. Do Ultima offer any tuning guidance on their site? I have a G on my S&S 107" engine in a Glide, which I had dyno tuned to get just right. Once you get it running that would be my advice.

 

Do you know what jets are in yours? Bet yourm107 would be close.

 

depends a bit on your elevation, i think that i'd try a 31 pilot/slow jet and a 74 or 76 main jet as a starting point. if you're at a higher elevation(one that affects your other tuning issues) start at 29.5 slow/pilot and 74 main and try it out and see. a dyno shop would be able to do this for you very quickly. if the 31 is still too lean, dont be afraid to move up to 32, you just might have to drop the main jet a size if you do.

m

 

According to my S&S FSM my 107" has a .031 Intermediate jet and . 76 main jet. My bike has been dyno tuned, but I don't know of any changes. I live in the UK and our gas differs from yours, hence having it tuned 'just so'. What the same FSM also shows are the settings for the S&S 113" engine! Same intermediate, but .078 main jet. In both cases idle set to 1 to 1.5 turns. Should provide you with a decent starting point, I hope!

 

"idle set to 1 to 1.5 turns."
grbrown, are you referring to idle mixture screw adjustment? Thanks.

Also thanks Marco..

 

Marco, yes, that many turns out from fully in. Only turn in the idle screw gently to find the stop.

 

There is no set mark for the idle mixture screw That's totally dependent on what size intermediate jet you are using. If you are using a small intermediate jet say a .0295 it's very possible you would go two to two and a half turns out maybe even three to get enough fuel to satisfy the motor at idle. If you're running a .031 intermediate jet then it's possible you would only be one and a half to two turns out on your idle mixture. screw Now when setting a main jet there's way too many variables in a motor to determine what size jet will comfortably work. Compression is one of those variables that will actually determine what size main check you would be using for the 2,800 RPM and up range.. If you're not running a thunderjet I would imagine a 78 or an 80 main jet would suffice very well.. But to truly know if you're making the right changes an AFR meter is the only way to determine what jets the motor requires. Without that you're just guessing and so is everyone else..

 

Gospel! Big engines with free flowing exhausts don't follow jetting tendencies.

 

Is the backing plate different for E & G carbs?