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Discussion Starter · #1 ·
So we started out in SLC. I guess the ride is called Wolf Creek. Absolutely beautiful. But I noticed that when I got up in the high elevations the bike was cutting out.... Hard. There was a certain spot in the throttle that I couldn't go past cause it would start bucking & cutting on me.

I've heard that the ninjas run lean... correct? This ride actually increases in elevation so...... wouldn't make the bike run rich??? With the lack of oxygen?

As soon as I came back down to salt lake it ran fine. The only real mod I have done is the exhaust mod ($36 exhaust mod, which is awesome)
 

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Ninjas do run lean. This is where cabs suck!
Increase in elevation = Rich

Decrease in elevation = Lean

Spooph will chime in!
 

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Discussion Starter · #3 ·
Spooph, give me some input brother :D

So if I shim the needles will this help (by all science it should right?)
 

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My old 4-runner had problems with going up the steep grade mountain elevations when I lived in CO. I would have the peddle mashed to the floor, engine screaming, and putt putting up the mountain in slow motion while other cars zoomed by me. Guess it was tuned for sea-level or maybe lack of O2.
 

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JT, you are correct, the higher you go, the richer the bike gets.

As you stated, the higher you go, the less air. You're looking for the best air/fuel mixture. So, if there's less air, you also need less gas to keep the air/fuel ratio the same. You will be loosing horsepower, but you won't get the strange throttle response. How does one not loose horsepower? Put on a turbo or supercharger, something that can shove more air into the engine.

What does this mean for you: Shimming the carbs means more fuel, richening up the mixture, which is the opposite of where you want to go. If you plan to spend a lot of time at elevation, you actually want to lean the carbs out, maybe half a jet size or a jet size, on the main jet. You might be able to get away with enrichening (backing out) your air/fuel mixture screw, which affects your "just-off", or "just past" idle stage, but I doubt it.

Here in CO I run my bike quite a bit on the lean side in the summer because I too like to play in the mountains. At my house (5,000ft) the bike is lean and hot. At 8,000ft she pulls beautifully, with a spot-on mixture, and at 10,000ft she stutters a bit, being quite rich by now.

In the winter I tend to run a bit on the rich side. On a nice warm day here in CO (40-50F) the bike is a little rich and pops in the exhaust, but in the morning and evening when I commute (10-30F), she runs like a raped ape, with a spot-on mixture. Nevermind the frozen fingers... :p I don't need to worry about elevation changes in the winter because there's too much sand, snow and even colder temperatures in the mountains, so I don't go there. You would be surprised what 20F can do the air/fuel of your bike....

I have modified my air box, but my exhaust is still stock (can you believe it, even after 20K miles?). I run 102 main jets in the winter, and 100 in the summer. My idle jet stays the same year round, it's a 39.5 (made with drill bits). My air/fuel mixture screw is 2.0 turns out in the winter, and 1.25 turns out in the summer.

Shoot me back some questions....
 

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Spooph...planning a trip to the Alps...Problem we have to ride there i will prolly adjust the carbs for the mountains and then reset it back for the trip home. I figure adjusting the cams might help but that is a lot of work and tinkering and not being near a legit shop may be beyond the capabilities we will be brining. I have a feeling that bring a carb'd bike to the mountains is going to make this ride a bit of a hassle. here is our route...


http://maps.google.com/maps?f=d&source=s_d&saddr=Lienz,+Austria&daddr=Bolzano,+Italy+to:pontresina,+Switzerland&hl=en&geocode=&mra=ls&dirflg=ht&doflg=ptm&sll=46.80382,11.68396&sspn=1.951417,3.521118&ie=UTF8&t=h&ll=46.604167,11.299438&spn=1.958646,3.521118&
 

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I think we will prolly trailer the bike there now... an idea of how fun the may be having we are only going 150 or so miles but it will take us almost 5 1/2 hours and the pics i have seen so far are awsome...so we will see more to come...this may sprout into a new thread it would seem
 

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KoelSlaw said:
Spooph...planning a trip to the Alps...Problem we have to ride there i will prolly adjust the carbs for the mountains and then reset it back for the trip home. I figure adjusting the cams might help but that is a lot of work and tinkering and not being near a legit shop may be beyond the capabilities we will be brining. I have a feeling that bring a carb'd bike to the mountains is going to make this ride a bit of a hassle

I thought Euro 250R's were fuel injected, no?
 
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