Has anyone tried Klotz CoX-Oc? It is a fuel oxygenating additive that's supposed to contain 37% oxygen. You add one gallon to 5 gals. of gas and you can supposedly use your near sea level jetting at high altitudes like Colorado. It's over $40/gal. but you get 6 gals of fuel and can use it with 2 or 4 strokes. If you're going for a long weekend, once a year, it would be way easier than messing around with jetting changes. One of the bike mags - sorry, don't remember which one, did a product review several months ago. They used it with a 2 stroke and had good success. Check out the Klotz site for more info - www.klotzlube.com. It's under motorcycles and additives.