anyone heard of pantyhose in place of an airfilter and a few extra plugs to go riding in lake city colorado?im out of texas carbs set at about 1500-1800 feet.im going about 9000-11000 feet.if anyone has an answer for me please let me know

 

I live in the valley near sea level, and that is what we jet for. (Sometimes we even ride at below sea level!) The mountain trailheads are at around 4,000', and from there we ride to over 11,000'....all in one days ride!

What we do is install a couple of Thunder TPI's in the airbox lid. As you ascend in altitude, you open it up to get more air, and as you descend, you close them back down to get less air. Above 9,000', I just pull the airbox lid off altogether. In a sense you are doing a rejet, but instead of adding less fuel, you are adding more air...end result is exactly the same....and a lot less trouble!!! http://www.thunderproducts.com/tpi_valve.htm


I noticed you mentioned the TRX250 (Recon or EX I presume???). On these, there isn't enough room in the lid for the TPI, so I just install a bunch of those UNI round vents. At sea level, they are taped over with duct tape, and as you ascend you start pulling the tape off to get more and more air. Not as convenient as the TPI, but it works. http://www.unifilter.com/onlin...alog/accessories.html


This system works great!!! No sense fooling around with a rejet and all that crap, unless you are going to move to high altitude permanently.

 

Yup, have done that before but I don't think going from 1800 to 11,000ft will fall in that category. When ridding in the desert I have ran the air box closed but when going up the mountains of AZ (5000 to 7500ft) removing the air box lid helped. Just remember, the factory jet for an ATV is almost always set a little rich. I live at about 5500ft and found the stock jetting for my Sportsman was way to rich. Had it rejeted to lean it out a little and it was still to rich. Found if I ran the ATV with no air filter lid it was perfect. Something I had done to the Scrambler 400 was installing a Dial-a-Jet. Google it and check it out. There are also some ATV mags that did altitude testing with this. A two stroke isn't as forgiving as a 4 stroke when it comes to jetting which means always having to change it. Got tired of that business so I put a Dial-a-Jet on it and its works great. Ran about $60 for the parts. Should be good from 0 to 10,000ft for a carb adjustment. As you go up or down in altitude you simply turn the little dial to richen or lean the carb. No more changing jets and it gives you a little better gas mileage to.

My feeling is removing the air box lid will not help at 11,000ft. Anyone else agree or disagree?

 

Factories tend to jet lean (especially on top), to help them meet emissions standards! So, you will be better off at moderate altitude than you think you will be.

The trouble with just yanking the airbox lid off at lower altitude, is that you have no regulation....it is all or nothing! With the TPI or UNI vents, you can fine adjust the air intake to match the altitude change, in real time! Like I said, I do remove my lid completely above 9,000'.

Don't make to big a deal out of this altitude thing! Lots of folks I ride with don't do anything to their stock jetted machines, and they still have a great ride!!!

 

<div class="FTQUOTE"><begin quote>Originally posted by: reconranger

Factories tend to jet lean (especially on top), to help them meet emissions standards! So, you will be better off at moderate altitude than you think you will be.



The trouble with just yanking the airbox lid off at lower altitude, is that you have no regulation....it is all or nothing! With the TPI or UNI vents, you can fine adjust the air intake to match the altitude change, in real time! Like I said, I do remove my lid completely above 9,000'.


Reconranger...California is a country unto itself (I think the 7th largest economy in the world). In most of the counties in Arizona we don't have emition control especially on motorcycles and ATV's. For that mater we don't even have emition controls on passenger vehicles. According to the dealer ship here (perhaps it's a Polaris and Kawi thing) they are jetted rich. If the stock jetting was left in my ATV's they run like crap, even blowing black smoke out the tail end while wanting to flood out once I go over 6500ft. I can understand why the ATV's sent to Cali are jetted lean considering the mass of regulations that have to be fallowed. So-Cal regs are not the rule for the rest of the country.

 

coooollllll!!!!!!!!!! thanks alot this will save me a few dollars.thanks again for the help...