HTMSteve

They don't appear to be and were new in 2013. I had the primary shaft out of one of the carbs because the progressive linkage cam was binding if the secondaries were open any more than 2 turns of the sec idle speed screw. The primaries would not fully close on their own. The shaft and base plate looked good.

HTMSteve

OK guys, resurrecting this post...since the last post I've played around a bit more with the 1050 doms and have now boost referenced primaries only and plugged secondaries. After modifying, I connected a mityvac hand pump just to check that there were no vac leaks, but the rear carb primary was sucking fuel into the mityvac hose, but it would hold a solid 10" vacuum on gauge without bleed down. At that time there were 6.5 PVs installed and I just thought that the rear had blown. I changed out the 6.5 PVs to 3.5 PVs a few weeks back, but didn't do the mityvac test again until today...guess what, fuel in the mityvac hose again from this same carb. Where is this coming from? I pulled off all fuel bowls and metering blocks today, going to tap the IFRs and install smaller size restrictors after removing the 0.041" IFRs that are in the lower position. I will use new gaskets when I reassemble, maybe that's all it is, but the blue gaskets look to be in good shape.

I know many of you gave me solid advice a few months back for carb tuning, and I have the tailpipes out at a shop now having O2 bungs welded in so I can use my LM-2 Christmas gift soon and check AFRs. Going to start my tune as follows: IJ .031", TSJ .059", IAB .055", .037" MAB, with square T-slot under primary blades, secondaries closed, and go from there with locked 32º timing. My goal here is to lessen the blower surge at idle, if possible and have a suitable idle speed to shift the XR, or have a small surge that dips to 800 RPM so I can time the shifts, but it won't die when shifting into gear like it does now, real PITA!
Thanks,
Steve

HTMSteve

I've played around a bit more with the 1050 doms and have now boost referenced primaries only and plugged secondaries. After modifying, I connected a mityvac hand pump just to check that there were no vac leaks, but the rear carb primary was sucking fuel into the mityvac hose, but it would hold a solid 10" vacuum on gauge without bleed down. At that time there were 6.5 PVs installed and I just thought that the rear had blown. I changed out the 6.5 PVs to 3.5 PVs a few weeks back, but didn't do the mityvac test again until today...guess what, fuel in the mityvac hose again from this same carb. Where is this coming from?

MILD THUNDER

iTrader: (3)

Where are you hooking the mityvac to?

HTMSteve

Connecting to the vacuum lines that would connect o the manifold and the other end is connected to the carb. I checked each carb individually to ensure no vac leaks, which seemed good. Each carb held 10" vac with no leak down.

MILD THUNDER

iTrader: (3)

So the boost reference ports you are pulling a vacuum to?

Did you check the metering blocks for any warpage and new fresh gaskets with bowl screws tight enough?

HTMSteve

Thanks MT,
Yes, the boost reference port. I have them off to drill and tap lower IFR holes for brass set screws and will check flatness, just haven't yet. Gaskets are the blue ones and I had reused them, but they all look to be in good shape. I have new gaskets and will use them when I reassemble. Bolts were not torqued, but reasonably tightened with a 3/8 drive craftsman ratchet without over tightening. There's not many areas around the PV vacuum well for fuel to leak from. Just above is the squirter hole and the gaskets are deeply impressed, but not torn anywhere. I'll put the new gaskets on and check Saturday on the boat and report back. What seems Wierd to me is that just a small amount of fuel gets into the hose and stops even though there's more fuel in the bowl. I would expect it to keep leaking until the bowl is empty. Maybe the vac is pulling the gasket into a sealing condition at some point. OK, I won't guess anymore for now, but if still leaks with new gasket and flatness check then I'll have to look deeper.

Steve

MILD THUNDER

iTrader: (3)

Definitely try some new fresh metering gaskets before anything, and report back.

SB

iTrader: (1)

x 2. And make sure they are the right ones.

Bawana

X3 about the gaskets... ALWAYS use new gaskets & only use the good ones. I had the same problem in the past.. I was using a cheaper brand gasket, and did vac test ... they didn't hold vac. Replaced with new holley blue gaskets and all good.