Going from sea level to 5000' + elevation- How to tune the carbs?

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nidyanazo

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I bought a lake house in the mountains where I'm keeping some of my motorcycles now, and the 'max is one of them.. (all the others have fuel injection)
The elevation is 5200', so the air density is less but the roads here are paradise. miles and miles and miles of perfectly paved twisting roads with very little traffic. :eusa_dance: So I just wanted to see what you guys think I should do with the carbs.. They have the stage 7 kit, and everything seems to be pretty good so far, but I was thinking about fiddling with the low speed air screws. What do you guys think? I should go leaner on them right? Less oxygen in the air, so lean out the mixture to compensate?
 
Correct. Stock main jets are 152.5 and those were set by Yamaha based 0 sea level. Generally, you want to lower the main jet one size per 1000 feet.

I have an old post Chris Webb...he's a CO boy who spent the time to tune his bike for the mountains. He floods it at low end and midrange for better control, throttle response but chokes it up top. Here's his jetting:

main jets: '145'
pilot fuel jets:'42.5'
pilot air jets #1 (PAJ1):'95'
pilot air jets #2 (PAJ2):'160'
 
I have tried every jetting combo known to man and carb up here, Denver. I used the vmax tech forum jetting, the exact set-up recommended here, dynajet, individual k&n, stage this and stage that. My bike would have good low end but flat midrange or killer top end but stumble between idle to mid circuit. I got some advise about going back to stock, airbox and jetting. My bike has a 4 to one kerker I work in Evergreen CO. on weekends and ride the streets of Denver all week. My machine runs and sounds incredible! STOCK at 5280.
 

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Nice Gents, and it looks good too!
I don't really want to go back to stock since I already have the 4-2-1 full exhaust and a new carbon can, the K&N's s7 jet kit, ign etc etc. I had it tuned perfectly for sea level, but now it seems to be down on power by like 10-20HP- it goes smoothly up through the rpms, but the low end is a bit sluggish (prob. too rich) and the top end is almost as good as down at sea level, so I'm not too worried about that. I'm guessing that leaning it out a tad will bring back the crispness. Thanks for the help fellas', I'll fiddle with the carbs and post again.
 

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