Quote: Since you have a BG carb you might be able to tune your cruise A/F where you like it with your regular jets. Then tune WOT with your Power Valve jets. A good carb will have replaceable power valve jets which can be changed. You have to remove the Power valve to get to them. Not sure where to buy them cheaply. Or they can be drilled out a little at a time.
I replaced the primary metering block with a "Quick Fuel" unit. The QF has tiny screw it "jets" in the metering block behind the power valve. I used the same #83 jets that I was using for a while. The A/F numbers went a bit richer at cruise. Maybe the QF block flows more fuel? I posted in the RACE forum but some responses caught me off guard. I was asked if I had annular or downleg boosters. Some mentioned IABs or IFRs. I wish I knew how to respond but once I get beyond jets and power valves, I'm not familiar with much else. I've looked for pictures of the annular and downleg boosters to see how they compare to mine but I can't find any that make sense to me. I don't have many gearheads nearby so I'm having a tough time here. Idle air bleeds? Idle Feed Restrictors? I bought this Demon in 2003. What I do know is that it is an 850 with Vacuum secondaries and it came with an electric choke. I don't have the actual model number written down but I thought it came with #85 primaries and #92 secondaries. Looking back, the tuning was heading the right way until I added the X pipe and Dynomax mufflers. Those changes sent the A/F numbers almost 2 points richer!
Idle Feed Restrictors? 
