Does altitude affect my carburettor?

I was going to upgrade my main jet from a .045 to a .049 ( a tip I found in an old post), but Fabio at Vespasupershop told me that with the altitude of Colorado, I should go a size or 2 down instead of up. He says restricting the fuel flow will lean out the fuel and give me better acceleration and possibly top speed (because of the altitude here, about 9000 feet above sea level).

Any thoughts?

Re: Does altitude affect my carburettor?

InfectedBootSector /

Yes, it does. It did in my Jeep anyway.... even 1000ft difference in my Jeep would make the carb go all wacky.

I would try the smaller sizes and see... be careful not to run too lean though... better to run too rich than too lean...

Go by the spark plug

It is no good for anyBODY to tell you what to do... you should 'listen' only to your own spark plug color after doing 'plug chops'.

You can read how to do them in the "How to fix your Moped"

click 'resources' and then 'articles' above.

And YES... high altitude generally means to go leaner (from low altitude) because the air is less dense.

(but not if you are already jetted correctly for high alt)

And no matter what you do (short of a turbocharger)... no engine makes as much HP at high altitude as thay do at sea level.

This is why the US will have trouble attacking terrorists in the high altitude of the Afghani mountains... some of the choppers we have can't even fly that high.

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