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Discussion Starter #1
Would stock carb work fine at this altitude, or further tweaking. My sea level settings were a challenge at 4000, and guess they may suck here.

I do have the ability to make changes even being on the road.
 

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My California 2003 stock jetted, no needle shimmed carb did OK from 5,000ft up to 9,500 ft with the mixture screw set ~1.75 revolutions out from seated. Since then I have enriched things a bit with mixture screw now at ~2.25 revolutions out but have not since been above ~8,000 ft. However bike still runs well with no "blubbering" or obvious malaise at 8,000 ft. California jetting is slightly leaner but you might get acceptable results with simply turning in your mixture screw a bit.
I would ride your bike as is in Salida and only tweak if it seems unacceptably weak. Colder Co. temps and any humidity might contribute to an effectively lower density altitude operating in your favor, or does that only work for aircraft?
 

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Discussion Starter #3
.... Colder Co. temps and any humidity might contribute to an effectively lower density altitude operating in your favor, or does that only work for aircraft?
I think aircraft are more sensitive to those specific changes......
 

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I think aircraft are more sensitive to those specific changes......
Not true. Aircraft only APPEAR to be more sensitive because they are generating a lot more power and ANY hiccup or loss of expected power REALLY gets your attention! :eek: All normally aspirated engines are affected by Density Altitude the same way, but the effects may be hidden at less than full power, which the TW certainly is going up a hill in 5th at 7,000 feet!

I forget which year yours is, but any post 2001 should have a 126 main jet if not modded, and at WOT should work OK up to about 9,000 feet. I only start to see some bogging in 5th gear above about 6,000....all the lower gears are fine and I have never experienced any difficulty starting up to 12,000. You might screw in your pilot jet to the bottom and back it out only 1 3/4 turns for that altitude, but that only affects idle and below 1/4 throttle mostly. I do have to fiddle with my idle all the time at altitude, though.

And Fred, not to put too fine a point on it, but the higher the humidity, the higher the Density Altitude. High, Hot, and Humid (and Heavy) are the three (or four) corners of the high altitude coffin for any non turbo aircraft.....and for us too, it's just that the penalty clause is not NEARLY as bad!........One of the many reasons I was happy to quit Flight Instructing in the Colorado mountains! :p
 

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Discussion Starter #6
TBH i can't remember the jet i used, 135 comes to mind, but my brain could make up any number at this point. In any case, i took it for a short stint today, at or below 30 seemed to run okay. It currently starts with no choke at all. open it up past mid and it gets squirrely. took it up about another 200 feet in altitude on a trail today....again at slow speeds it appears okay. im only going to be here one more day so no point in messing with it and in 3 days i'll be at 1400' and lower after that...so....

ill be checking local trails here in Salida and throw up another vid in the afternoon.
 

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A 135?!!! Jeez, if that's true no WONDER it won't run well at altitude! :eek: I've never heard of anyone going larger than 132. I'm not aware there even IS a 135 available. Even a 130 would cause your problems at that altitude. Get your ass back down to sea level where it belongs! :D:p
 

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Discussion Starter #8
A 135?!!! Jeez, if that's true no WONDER it won't run well at altitude! :eek: I've never heard of anyone going larger than 132. I'm not aware there even IS a 135 available. Even a 130 would cause your problems at that altitude. Get your ass back down to sea level where it belongs! :D:p
It was the procycle mod pack they have, so whatever was in there, based on what i researched on here was what i used. it was too long ago to remember. :rolleyes:
 

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Well, when you end up in Ft. Carson years from now you can stick a 126 or 122 in there....:D;) So much great riding around C. Springs....great memories.
 
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