I have spent considerable time in the last 30 days farting around with my 3255-1 (BV), which I bought from Carl's supposedly "fully restored and ready to bolt on." Previously I have been running a Mighty Demon 750 annular, so I had a pretty good performance baseline. I fought with the 3255 for two weeks fouling plugs and loading up before sending it to Keith Craft for a baseline tune. Last thing I tried before boxing it up was a 4.5PV and that didn't help. Ironically the only mod he made was a 4.5 PV and said it ran great on the dyno. Maybe my PV was bad. Carb came back from Keith, I installed it out of the box and it rewarded me by dumping the number 5 cylinder full of raw gas. Got that mess cleaned up and it was with considerable effort that I finally got the engine just started and idling. Keith sent it back with 73/85 jets (stock sizes I believe) and the 4.5 PV was to account for my 7-8" idle vacuum. Through trial and error using my 02 sensor and looking at the plugs I have since gone up to 77/85 on the jetting, changed to a more aggressive pump cam and increased the discharge nozzle from 25 to 31. I have confirmed the secondaries are opening but I sure can't feel it; even with the lightest spring its almost unnoticeable. And on a few occasions it has coughed hard at 3500-4000+ rpms while winding up in the top of the upper gears, right where you'd expect to feel the secondaries. I can nail it in first with the Demon and all hell breaks lose. With this carb, its anemic and will hardly spin the tires from a dead start.
Good news is it idles beautifully, even better than the Demon. The cam just lopes nicely at 950 rpms and its really sweet. So I got that goin' for me.
I'd really like to hear from someone who has been able to get this carb to perform. I think I am just about done with it.