Overview

There is no one correct set of jets to use, however there are some good ballpark settings for each application (i.e. 12A stock, street-port, etc.). Racing Beat delivered a carburetor that was set up to provide good performance out of the box with only minor tweaking of the idle mixture screw. Of course even that setup is probably not optimum for all applications as other engine modifications and elevation play a role. The average person doesn’t have the time, equipment, and knowledge to find the optimum set-up. My goal with this page is to provide the set-up that Racing Beat delivered (it works for most) and also information from other people on their individual set-ups.

This section may never be complete since I can't be sure of the exact settings that Racing Beat used. Also it is quite possible that Racing Beat changed their jetting settings over time. Racing Beat modified the carburetor as delivered by Dellorto. I have some information here on the changes they made but they may not be correct for all configurations.

**Note** The settings for the 13B, from Joe Chapman, contain the best information on the modifications that Racing Beat made. Some of these mods may pertain to 12A applications. It is worth taking a look at that, especially for acclerator pump mods.

12A Engines

12A Stock (from David Muoio)

These settings are from my carburetor as delivered from Racing Beat. In a few cases I am not 100% sure of the jet size and I won’t tear my carburetor apart just to find out. After my last experience with the pump jet, I need a good reason to tear into it again.

Jet	Size	Notes
Main Emulsion Tube	#7772.8
Main Fuel Jet	#230
Main Air Jet	#230
Idle Holder/Emulsion Tube	#7850.4
Idle Jet	#75
Accelerator Pump Jet	#90	Not positive on this.
Needle and Seat	#300	Pretty sure as it's the only one that RB had in their catalog.

12A Stock (from Will Claypole)

This is a write-up by Will on his experience getting the Dellorto working on a stock 12A. Will did considerable tinkering with the carburetor to improve the original RB setup. Major changes include modifying the float level and the accelerator pump.

12A Street-Port (from Brad Page)

This is a write-up by Brad on his experience getting the Dellorto to work well with his street-ported 12A. He found that the intake manifold by Racing Beat to be the reason why people (including RB) have problems getting the Dellorto to work well with a ported engine.

13B Engines