Hey gang,
I'm operating both '04.5 model machines without issue between sea level and 3000' MSL. I'll be taking both machines on a hunting trip to Colorado in early November which I'll have the potential for running from 5000' to maybe 8000' MSL and possibly above. Can anyone give me some suggestions on what I'll need to do to get decent performance at those altitudes? Obviously I'll need to lean the fuel mixtures but I have never really messed with rejetting anything, in the airplane we just adjust fuel mix for optimum performance with the twist of a ****. My trucks are all fuel injected! [img]i/expressions/face-icon-small-blush.gif[/img]

Is it a pain to get to the jets? Does it require a significant teardown or is it done relatively quickly? What kind of jets should I be looking to get? Thanks for any help in advance!

~TD

 

TreeDoc,

First of all I have to say is that I am envious, since I can't make out there (CO) this year, but that'll make next year all tha much sweeter...

I live at a round 1600 ft, but do the majority of riding between 1800 - 2400. When I was out there we camped at bout 7800 ft, amd we did most of our riding at around 9600 - 10500. I did not have ot rejet to run at those ranges, I did not see any significant loss in power, but when we went to above that like 11000+ it was quite noticeable. From what I read in some other posts, it seems the 03 Carb update helps a little with the altitude, something with using less fuel when colder, and needing less fuel with altitude.... I am also running a Heelclicker with a 1.2/4.3/3.3 with the factory spring in the primary, I think that helped as you are to adjust clutching for altitude as well,

With that being said I've been want ot try the Dial a jet just so I don't cause any damage to my engine, the dial a jet supposedly works like the **** on your airplane. Maybe some folks will chime in and share their experiences on that. Otherwise you need to get a different jet. Don't forget about the clutches too...

ZMan079

 

The 400 will have to be jetted - they are too rich from the factory to run up here. The 500 I am not sure about, but I'd bet it'll need it too.

I'd probably go with a 162.5 main in the 400 and lean out the idle mixture a bit. On the 500, look in the owners manual jetting chart and drop one size from the recommended high altitude jet.

The carb is not hard to work on and can be jetted without completely removing it from the ATV. You just need to get it turned enough to get access to the bowl screws.

Look for jets locally, if you order the minimum is usually 4 jets.