Just picked up a rigid with a 2002 Buell Cyclone engine. Former owner put on an S&S Super E with a Thunderjet, but the whole thing looks like a mess and the bike runs rough in the mid range.

The engine is built but still has stock 10:1. I am wondering if I am able to simply swap out the Super E for a Mikuni? And if I do that - do I need the larger HSR45mm Mikuni or can I stick with the 42mm? (The Super E is apparently closer to 47mm)

Any input appreciated!

 

http://www.yoshimura-jp.com/en/produ...ine/yd-mjn.php

This link is for the latest and greatest carb.
Do not some say that flat sides help with upper rpm, where round help coming on throttle.

I can't answer you question directly whether a 47, 45 or 42 is best.
What I can write to ask the question if you have gone through the carb you have now, ensuring it is operating correctly, and then whether you changed needles, jets, float hight and all the adjustment points?

Good luck...carb tuning can be time consuming.

 

The HSR42 will be the ticket.