Hi Ross
Thanks for your respond but would you use the pink cams in front and rear and both 30cc pumps. Now what I have is blue cam front and brown cam rear,30cc pump front and 50cc pump rear. Just trying to understand a good starting point. I know everyones engine likes something a little different.
So, I look at enrichment using an accelerator pump as a hatchet versus a power valve which is a carving knife. I try to minimize as much pump shot as I can, however, pump shot is required, so don't let me infer it's bad. It's just not metered or atomized as fine as something coming through a booster or transition slot.
First, I don't see a reason for a 50cc secondary pump unless you are running alcohol. I haven't seen one that needed it yet, although I suppose a tunnel ram or very low vacuum heavily ported Victor with a big open spacer could like one, and the area of the primaries are the same as the secondaries so I don't see a reason for it with a square bore carb on gasoline. If you need 50 cc, up to 66% more fuel depending on cam, using gasoline, seems like there is something wrong. So I use dual 30cc pumps. That being said, if I had a good carb I likely wouldn't take it apart just to start.
Second, the blue cam up front is a little different. I like that cam because it comes on quick and pumps a bit more. Sort of counter to my original statement, but it often can offset a marginal transition a little, especially in HP series and silver bodied carbs (like the Avengers) that have a funky emulsion well that isn't as responsive. Hatchet carving a turkey, but it's one of those that seems to work well when the engine wants it. When I use those, I use the smallest shooter I can, usually a 28-30 on the 4781, because I like it to come in hard and hang for a bit, as opposed to a big shooter that will dump fuel
My recommendation: If this was a known good carb and ran well the way it's set up, that is where I start. If it is a new carb, as delivered is where I start. If it is an unknown carb or needs a rebuild, I generally return to as delivered for every passage and adjustment, however, in that case, if I had a pump arm, cam, and housing, I would swap to a 30 cc pump out back.