i have a 107" s&s motor and would like to know which size mikuni carb to use for best performance.?

Answer 1

Mikuini HSR 45 would probably be your best choice ,but you could get away with a 42. I've run both on Big Inch T.P. engines and found it a bit easier to get the jetting perfect on the 45.

Answer 2

I also have an 107 cu in S&S, but I run a S&S Shorty Super "G" carb.
On the S&S carbs, an "E" is good up to 100 cu in. Over that and you need a "G" to feed it. A "G" doesn't have the low to mid range response that a "E" does, but it will feed the bigger inches.
As far as a Mikuni, sorry, no idea what size you need.

Answer 3

A bigassed one.........