So, I bought my bike with the Ferracci mikuni flatslide conversion on it already. Pump had always been active, and PO reported bike ran poorly when pump would loose it's connection (bad power connection to the pump in the past had provided this experience).

Pump died, and gravity feed was more than adequate (I removed all the fuel pump plumbing inside the tank so the petcock feeds from the bottom of the tank now).

I find that the bike is quite lean now. I tried going to a bigger needle valve to be sure that wasn't a restriction, and went from a 15 to a 20 pilot, but still it wants full choke, and revs up high at idle.

Would the "pressure" provided by the old pump actually effect the jetting of the bike? Seems odd to me, but that seems to be what's happened (unless an unrelated air leak has developed someplace recently).

Thoughts?

most definitely a pump will effect the level of gas in the float bowl as well as the rate at which it fills effectively richening the mixture. Most likely you can raise the float level to bring things back in line as long as gravity fills the chamber fast enough to maintain the level

seems odd that that would effect it at IDLE, though. Oh well. I think I need to wait for these new float valves to show up before I do anything. I switched from the 1.8 to a 3.0 since there's no pump to push the fuel through the valve.

OK - apparently I introduced another variable at some point - Cables.

Setting a little cable adjustment allowed the carbs to close. Bike runs great, starts well, and seems to like the change from a 15 to a 20 pilot. Hopefully that's it.

If you ever feel that its not getting enough fuel, (mostly under throttle on a long climb) you can still put on a vacuum operated fuel pump off of a Monster, or other bike. There's a recent thread on that somewhere here.

Cheers, Phil

always pays to check the basic setup when troubleshooting to avoid putting the cart before the horse

vacuum pump thread is here