carb tuning

Turn your air screws in 1/2 turn

Personally I like to go with 1/4 turn at a time when adjusting the idle air mixture. 1/2 turn is quite a bit of change.

If it was fine before and just started doing that I would say pull the carbs and check the pilots. They might have some varnish or something in them, that will cause the lean condition at idle you are experiencing.

I would also try the air screw. I've seen even 1/8 turn make a difference.
If that doesn't work, maybe with the pipes and bore, you need to run the next size up in pilot jet? Just a thought.
Engagement should be around 3500-4000 for best results.

D

At that altitude you are losing HP with them twin pipes. Those pipes only made 3 or 4 HP at sea level at peak and lost HP everywhere else. The 96' and newer 500 Y-pipe/pipe combo is the best set up for that motor IMO.

Back in the day DYNOTECH research tested them. You might be able to find the article on line.

As for your issue, like others said, clean the pilots real good and then adjust the airscew. Sounds like you are righ ton for the pilots which is a good place to be. You can fine tune with the air screw for temp changes.

I forget what weights I ran @ 6-9K but I always jetted 2 sizes leaner than what Polaris recommended, for the secondary I ran a Polaris 40-36 with a red spring in #3, in the primary I ran an Almond round and I don't remember the weights. Maybe 10MB. Shoot for 8100 on the tach.

Looking back I think I would run a 40-34. I had a 136X1.5 camoplast track on that machine geared to 20-39 with 8th drivers.