I used them exclusivly back when I raced 20 years ago. The third circuit improved the fickle Mikuni and aftermarket variation carbs that don't have it. All carbs can work with tuning but you have a number of adjustable variables including pop off, needle, HS jetting, low speed jetting, HS screw and LS screw. Realistically the general racer doesn't have the time or knowhow to bury their head under the seat at every race... so they don't win. Watercraft racing has drastic changes in water and air temps. I was a large team owner that tried every brand available so I won't name them all. As I said they all worked but the difference with the SRE (Scotts design for Me and B0) Turned all of those choices into a single jet choice carb and any tuning left all year was in the screws. I won a ridiculous amount of races including both moto's at finals. Only one time did I need to make a LS screw adjustment was the earthquake year in Havasu when the barometer was crazy. The rotary valve Seadoo is the only application I have used them on, maybe that plays a part with the necessity? I used 46's on limiteds and Superstocks, I also used 48's on Superstocks. The differance was a little better low end vs top end. Both could win. I was recently asked to build some vintage X4 racers for the surge in popularity again, and the one part I said that I wouldn't do it if they couldn't find SRE's. I can still find most everything else. We have a couple sets already but since we mentioned the builds a few days ago I have been asked to make more. I would be interested in talking to you
