I seem to open my carb up on a regular basis and change something trying to tweak the beast into liking elevations of 5000 to 11000 feet. One thing I have found that when crossing the Rockies at anything less that 65 MPH requires 4th gear, 5th is for flat land hauling -oh no I used a word I shouldn't have- even with the 3.50's in the rear. 

What I have noted around my neck of the woods (8500') is that any hill at 55 MPH causes the AFR to read 10.0 (the richest the gauge will read) as soon as the Power Valve opens. I had to up the main jets a couple of sizes to cure the super lean transition before the PV opened. This took a lot of work testing different PV's and jets to get dialed in. As stated before once the PV opens the AFR goes super rich. In fact it was so rich going over Vail pass last month the engine acted like it was running out of fuel, or had too much. Very hard to tell when running pig rich.

So I popped the carb of the intake and took a look at the PV Channels thinking I could put restrictors in them. Holy Trash Can Batman! The PV channels had brass restrictors pressed in and they are 0.062 inches in diameter, roughly the same size as the #60 jets I run in the primary side. No wonder it runs so rich when the power valve opens. 

My test today involved putting .032" safety wire in the restrictors to restrict them more. I did some quick calculation of surface area of the restrictors with and without the safety wire. I originally was going to try .025" wire but opted for the .032" brass wire and would have gone .041" had I had any. I used the brass as it is softer than aluminum so if wear occurs the brass takes the beating. I then took it for a spin and the AFR stayed in the high 11's low 12's.

Success at altitude. I'm heading back over the hill to Grand Junction and am eager to see how the latest changes work.