Plan on going to Thunder on the Mountain in July.Will be changing from a low altitude high temp. to a higher altitude lower temp what will I expect to happen in performance???

Sorry the event is in Brianhead UT. and I`m in Vegas!!<br><br>Post edited by: vegasdave, at: 2006/05/25 09:34

you're bike will get richer... if you're right on the money, or a little lean, you shouldn't see any problems... especially since roadstars run great rich... but I'm worried about people who have their star's set up really rich, they may have some issues... might even make a sticky valve issue pop up / get worse... Star
Days is in longmount colorado... and will have some runs up into the mountains... and will have the same issues ~Guido<br><br>Post edited by: davehrn, at: 2006/05/25 09:50

Dave,

Davehrn is right, you will get richer as you get to higher altitudes. Fortunately, the stock carb on a roadstar is a &quot;Constant Velocity&quot; (CV) carburetor. CV carbs have slides that use vacuum and air pressure to raise the slide rather than throttle position. The throttle position only changes the butterfly valve opening.

This means the carb is less sensitive to altitude changes than other types of carbs (like a flatslide). As the air gets thinner, there is less air pressure to raise the slide, the slide stays lower than it would in at lower altitudes (like Vegas), and it keeps the air pressure going through the throat of the carb fairly constant. The flatslide guys making the same trip will be markedly more effected than you will.

As Davehrn said, if your jetting is close to being right, you will most likely not have to mess with it. If you want to just play it safe on the valve-carbon issue, take some Techron with you and add Techron's recommended amount to the tank whenever you fill up. It will help to fight the problem.

The CV carbs are so good at thier job that a lot of small aircraft use them. Keeps thier mix much more constant and makes the aircraft more reliable.

GRAM

Since I live about 15 minutes from Longmont,COLO. I guess I won't have to worry about the altitude change for Star Days!!!

You guys should have no problems. Mine was jetted for 6000ft. elevation living in Cheyenne &amp; numerous rides to Estes Park, tundra above the treeline around 10,000ft. bike runs good..