I have a '91 Pz II w/ Aaen pipe but I'm 3-6k feet. 150 mains, 105 pilots. Standard butterfly carbs. Not great info for your elevation but it might give you an idea where to start. If you're staring from scratch.
Are u guys running the updated primary nozzle with two holes in it? I have an Aaen pipe on a sled I bought this fall. Burned the piston on Pto side. I had richened up the pilot to 110, the mains to 143.5, the 2a main nozzle. It still melted a piston at 4500 plus feet. Going to run the two hole nozzle and see what happens.
I believe the updated nozzle helped prevent mid-range lean condition that caused many a melted piston in the Phazers. This was considered a must do mod if you are running an aftermarket pipe. And probably reccomended even for stock sleds. Check Totally Yamaha's forums for more info on this. Do you have the updated piston? They were referred to as "SX" pistons. The skirt on the intake side was cut away to open the entire intake port while drawing air/fuel mix from the carb. Those may make a difference on a piped engine, didn't make much difference on my stock engine/exhaust set-up. I probably got more performance from the new rings.
