Topica Loopframe_Guzzi Archive


Subject: Re: Dellorto VHB 29C settings at altitude

Author: Giller,Bruce C.

Date: Aug 29, 2003, 11:42 AM

Post ID: 1714333172



Sean,
Godfrey DiGiorgi had this information about jetting for high altitudes.
I asked the question when my wife and I were going to be traveling in
Colorado (Durango, Co).

Bruce

'72 Eldo

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As you come west, you will probably find that it will run richer as the
elevation increases. Have on hand two sizes smaller main and idle jets;
the typical adjustment, if needed, is about one step size per 3000 foot
elevation. For instance, you start at sea level and you get to somewhere
that is about 3500' average elevation, your hypothetical main and idle
jets are 130 and 55 respectively. Swap them for a 125 and 52.5, drop the
needle one notch. By the time you get to Denver, at 5500 feet, you'll
likely find you need to do it again, going to a 120 and 50 (you probably
cant drop the needle again,so just leave it alone).

IN practice, I've often just left the idle and needle alone, just changed
the main, if I wasn't going to be in a particular area for very long.

Godfrey

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Sean Flanagan wrote:
 
Greetings all-

Does anyone use these carbs at 7000 feet? I have a pair on my '71 Ambo
project, which are currently set at the factory manual settings, using the
stock parts. I'd be grateful to know the settings/jets folks are
successfully using at this (or similar) altitude, or information resources
to point me in the right direction.

Thanks in advance, have a great weekend!
Sean in Flagstaff, Arizona USA

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