Magneti-Marelli Injection to Carburetor Conversion

1. Introduction

Do you own a late '90 or early 2000 TwinCam Harley-Davidson with Magneti-Marelli injection which gives you headache for not being able to find anyone who could tune it correctly for the long run and for which you would like to find a solution? If yes, then you really have 3 valid solutions:

Convert it to another injection system such as the ThunderMax.
Convert it to carbureted with open market components including the ignition system.
Convert it to a carbureted equivalent of the Stock Harley of the same year of construction.

This article will cover the latter where one of our customers “Nils” converted his 2000 Harley Road King from a Magneti-Marelli Injection system to a 2000 Road King Carbureted model.

Should you have any question for Nils, please contact us and we will forward your request.

2. Objective

The objective of the modification is to convert this 2000 injection model to a same year carbureted model. That is with using OEM components and keeping the data link and Harley OEM diagnostics capability.

On the injection models the ignition is taking care by the same ECM as the injection. It is therefore required to install a new ignition system similar to the one originally installed on the carbureted models.

Picture 1 The Bike after Successful conversion to Carb

Note that for this project, Nils selected the following options:

44mm CV carburetor
SE big bore intake manifold
Stock OEM ignition module
Performance Machine MaxHP Contrast Cut Air Cleaner

3. List of Parts

Note that since the carburetor model wiring harness (32435-99 or equivalent for your model) is not available anymore, it had to be re-created with a combination of new OEM parts and some re-used parts from the original bike. If you can fine such a harness from your local dealer or from the junk yard, you could simplify the electrical work significantly.

Here is the list of OEM parts used for the conversion:

1	99456-00B	Parts manual (optional, but useful); need to adapt to your model year
1	99483-00A	Service manual (optional but useful); need to adapt to your model year
1	27934-99	Carburetor 44mm
1	29229-88B	Choke command
1	29635-99	Intake manifold, big bore for 44mm carb
1	38723-99	Clip, MAP sensor if using 32417-10
1	68042-99	Screw MAP sensor if using 32417-10
1	16315-99	Top engine mount
1	32478-99	Original Ignition module or 32720-01C 7000 SE Ignition Module
1	62052	Pingel fuel tank adapter 0705-0030, Marelli injection
1	(21-294)	Pingel 22mm valve, polish aluminum
1	56376-96	throttle control cable assy
1	56375-96	idle control cable assy
1	61326-95	Tank gasket
1	0206-2081-BM	PM Max HP Air Cleaner Contrast Cut
		Harness ignition components
3	72033-93	Socket terminal
1	72119-94BK	Connector body
1	72139-94GY	Connector
2	72159-94	Socket Lock
4	72190-94	Stamped and formed pins
23	72191-94	Socket pins
8	72195-94	Seal pins
3	72213-94	Terminal, 18-20 gauge
1	72230-98	Socket housing 3-way
1	72280-95	Connector 3-way, TPS
2	74190-98	Pin terminal
2	74191-98	Socket terminal

Here is the list of parts that have been re-used from the original bike that you may or may not be able to re-use those depending on your bike model:

1	32417-10	MAP sensor (depending on the bike, could reuse original MAP sensor)
1	69123-92A	Horn mount rubber
		Harness ignition components
1	74102-98BK	Pin housing 2-way black
1	74152-98	Socket lock 2-way
1	72231-98	Secondary lock 3-way
2	10065	Cable strap
1	72214-94	Cable seal
1	72199-94	Connector
1	72144-94	4 pin secondary lock
2	72164-94A	Plug 4-way pin connector rubber
1	74112-98BK	Socket housing 2-way black
1	72158-94	Secondary lock
1	72138-94GY	Sealed socket housing gray 8-socket
1	74142-98	Pin lock 2-way

4. The Work, in pictures

Total estimated time for the rebuild: 8 hours

Picture 2 - Before the start

Picture 3 - Remove the cover and the air filter

Picture 4 - Remove the instrument panel

Picture 5 - Remove the cover of the gas tank.

Picture 6 - Parts that need to be taken out of the gas tank.

You can now re assemble the fuel tank cover with the fuel gauge and remove the fuel tank from the bike.

Picture 7 – Bike with the fuel tank removed

Picture 8 - Remove the Magneti-Marelli fuel injection intake unit

Picture 9 – Removed unit.

Picture 10 – Cylinder view with the Injection Manifold removed

Picture 11 – Install the new CV SE carb manifold

Picture 12 – Install the new carburetor

This is pretty much it on the mechanical side… Now the next step is the electrical wiring… To do this you need to refer to the service and parts manual. As previously said if you can find a carburetor wire harness, you can skip pictures 13 to 18 and just replace the harness.

If not, then you will need to re-create one and you will need both the parts manual for part references and the Service manual for the related schematics. In doing this you will need to carefully follow the wire colors and re-connect them to the new connectors.