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Pegasus Fuel Injection and Ignition System Install

On The Fastest Panhead In The World, It Fits Anything!

By Mil Blair and Wrench with photos by Sin Wu
6/11/2010 3:37:41 AM

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Finally-a fuel injection system that really works! Pegasus introduces the PFI-V Electronic Fuel Injection and Ignition Control System!

Not just a replacement ECU but an ENTIRE engine management system for any V-Twin Engine!!! Kit includes everything you need for a turn-key system; throttle body, fuel injectors, ECU, sensors, fuel pump, ignition coils, wiring harness, and all mounting brackets!

What can electronic engine management do for you? By combining both electronic fuel injection and ignition control into a single package, you can expect: much more power, better fuel economy, crisper throttle response, easier starts, and complete adjustability.

Here are all the elements to the complete, tightly organized Pegasus system. We didn’t use all of them due to our Assalt Weapan, Bonneville Bike configuration.

Key Features Include:
Advanced semiconductor electronics
Controls both fuel and ignition
Sequential timed injection
Single fire ignition
Enhanced fuel atomization
Multiple spark discharge
Easy adjustments by rotary switch, PDA, or laptop
Uses automotive sensors-available everywhere
Teflon coated, silver alloy wire and weatherproof connectors
Machined from billet aluminum- huge 53mm throttle!
Easy to tune-use the spark plug method or use our closed loop control and dyno tuning!

The PFI-V system is a self-contained engine management system designed specifically for V-twin motorcycle engines. It is not a “replacement” brain for a motorcycle already equipped with fuel injection. There are just too many benefits that you see when you switch to the PFI system to not consider it, especially on larger engines! –

PFICOMM is our computer communication program used to alter the files stored in the PFI brain. It will allow you to modify parameters as well as maps, store them in a file, load them into the brain, and save your changes on the fly!


Things to think about prior to installation.

• Poorly installed intake and exhaust manifolds can cause air leaks, which can lead to improper air-fuel mixtures and exhaust backfires. Make sure you tighten fasteners to their proper torque ratings.

• Not all air filters are the same! Make sure your air filter system is free flowing. A large volume air system acts as a plenum and can help increase useable power. Gooseneck-style intakes actually help with tuning, as the intake manifold is much too short on most engines.

• Most motorcycles are run for short periods of time, then they sit. Fuel in a float bowl can get “gummy,” leading to main jet problems. The same is true for fuel injection. Make sure you use a gasoline additive in your gas tank to clean your fuel injectors and fuel filter on a regular basis.

Please make sure your engine is in proper mechanical state before installing a PFI system on your bike, as there is no point in trying to tune a bike with a mechanical problem. If you feel there might be a problem with your engine, have a mechanic perform a compression test, leak-down test, change spark plugs, etc. before installing your PFI system.

This is the old stock configuration ignition pick-up wheel.

Hardware Installation

The PFI system consists of two hardware sub-assemblies (1) Throttle assembly (2) Coil assembly. The throttle assembly resembles a carburetor except it has the brain mounted on top of it, plus injectors on the bottom and a throttle position sensor (TPS) on the side.

We didn’t use the standard Pegasus top motormount/coils/fuel pump system and stashed the Fuel Pump under the seat.

The coil assembly contains the coil, fuel pump, electrical components, and pressure regulator. There is also a unique multi- tooth ignition pickup wheel, which replaces the stock one in the ignition cone, but we use the stock ignition pickup sensor.

This pickup wheel, with its many teeth, is the key to sequential fuel injection and single fire ignition.


The throttle assembly is designed to attach to an S&S Super G (53 mm diameter hole) or equivalent intake manifold. If you do not have one on your bike you can purchase one directly from BDL or from S&S, or from anyone that makes such a manifold.

We didn’t use the stock Pegasus system, but used our stationary mounted Dyna Coils.

The coil assembly is already attached to the supplied top engine motor mount designed for rigid mounted engines. If you have a bike with a rubber-mounted engine, you can use a special adapter available from BDL.


1. ATTACHING THE THROTTLE ASSEMBLY-Using the supplied 3/8-16 x 1.25 bolts, attach the throttle assembly to the intake manifold using the included insulator block using a light film of silicone sealer. Note: It is imperative that you use the supplied bolts as longer ones may interfere with the brain and locktite is recommended.

This air filter backing plate is designed for stock applications, but I’ll make it work on a basically Shovelhead engine configuration.

2. ATTACHING THE THROTTLE SUPPORT PLATES-Attach the throttle support plate and your air filter backing plate to the front of the throttle. Connect the filter support plates to the cylinder head breather holes using the stock breather bolts.

Pegasus Banner



3. ATTACHING THE THROTTLE CABLES-Loosen the throttle cables at the throttle grip, then install the barrels at the cable ends in the throttle wheel. Make sure there is enough play in the system to allow the return cable to function properly.

It is imperative you use a dual cable system as a single cable system is not reliable. MAKE SURE THE THROTTLE OPENS WHEN THE THROTTLE GRIP IS TURNED. In other words, do not install the throttle cables backward.

Mil installing the Pegasus timing wheel.

4. INSTALLING THE IGNITION PICKUP WHEEL-Remove the ignition pickup dust cover and stock pickup wheel. If you have an aftermarket ignition system you must remove it as well. Remove the engine timing plug and rotate the engine until it is at top dead center with the camshaft key slot in the position shown. Install the supplied pickup wheel on the camshaft making sure the alignment pin fits securely in the camshaft key slot. Be sure to use Loctite or equivalent thread locking compound on the supplied bolt.

Throttle assembly installation is complete.

Keyway, not shown, must be oriented at 8 o’clock when engine is at TDC. If keyway is at 2 o’clock when TDC mark is visible, you must rotate crank one complete revolution. Pickup wheel installed, set screw positioned in cam keyway to align. Thread fastening compound must be used on the center bolt.

5. INSTALLING THE COIL ASSEMBLY-On to the coil assembly. Remove YOUR top engine motor mount and ignition coils. Replace it with the PFI coil assembly while making sure to connect the 6-pin waterproof Deutch electrical connector between the throttle assembly and the coil assembly. Before removing your coil(s) mark the electrical wire (power wire) used to power the coils, as this is the wire that turns on the PFI system. More on this later.

High pressure fuel filter.

6. CONNECTING THE FUEL SYSTEM-The PFI kit contains a fuel pump mounted on the motor-mount bracket, with three high- pressure fuel lines and a special fuel filter. You CANNOT use a low-pressure fuel filter or stock fuel lines with this fuel injection system!! The kit comes with a special EFI petcock.

You can’t see it much, but the special Pegasus Petcock is on the left. It affords a performance outlet and completely separate return.

Start by draining the gas from the tank, then remove the old petcock; install ours. Connect the first fuel line between the petcock and the top of the fuel pump.

Here’s a short course in hydraulic brake line fab, using the finest tools. First the clean cut.

Here’s the order of assembly.

Work this collar over the braid until it’s fully seated. Don’t give up.

This is the master’s tool to lock and press the coupling together.

These mandrels hold the braided line and collar perfectly still for pressing.

Hang on.

The operation was underway.

Connect the second fuel line (#3 AN braided line) between the fuel pump outlet and the fuel rail inlet fitting. Now, connect the last line (fuel return) from the bottom of the fuel rail to the petcock. Make sure all the fuel lines are TIGHT!!

This shows the rubber return line to the tank and the high pressure braided line from the fuel pump.

You can now install the bolts holding the coil assembly bracket to the engine, as well as the top motor mount (not shown).

Pegasus Banner



7. BATTERY/SWITCH CONNECTIONS-Now you are ready to make the rest of the electrical connections. Note there are only three wires to connect the battery power (POSITIVE, RED/WHITE), the battery ground (NEGATIVE, BLACK), and ignition/run power (POSITIVE, RED AND LABELED IGNITION/RUN)!

These wires MUST be connected DIRECTLY to the positive and negative terminals of the battery and the ignition/run switch and nowhere else. Do not connect the three-pin connector to the ignition pickup at this time. Connect the six pin Detuch connector between the two assemblies, then tighten all bolts to the required torque specifications, as the motor mount controls the upper vibration of the engine.


8. SPARK PLUG WIRES-We have included special anti-EMI Magnecor spark plug wires.....use only these wires. Other wires, especially solid core, do not suppress electromagnetic signals and can interfere with the brain.


9. A QUICK TEST-At this point, most of the installation is complete. If all wires are connected properly: Flip on the main power switch. You should hear the fuel pump “whirr” for four seconds...then turn off. This is normal as the fuel pump only runs when the engine is running. Now look at the brain. The red LED should be on. If not, go to troubleshooting.


10. CONNECTING THE IGNITION PICKUP-If the pump runs and the red LED turned on, all is well. Turn off the main switch. It is time to install the ignition pickup and set the base timing. First, thread the three wires of the supplied ignition pickup through the hole in EVO nose cone. Press the wires into the supplied DEUSTCH connector as shown below while making sure to place wire #1 in position 1, wire #2 in position 2, and wire #3 in position 3. Refer to the included timing diagram if needed. Then connect this connector to the mating 3-pin connector on the brain. DO NOT INSTALL WIRES INCORRECTLY AS THIS MAY RESULT A IN DIRECT SHORT!!


11. SETTING THE BASE TIMING-Is the engine still at top dead center? It has to be to perform the next step. Install the ignition pickup loosely. Turn the pickup COUNTER- CLOCKWISE as far as it can go. Turn the main switch on. The green LED on the brain should be on. Now rotate the pickup CLOCKWISE (slowly) until the green LED on the brain turns off, then keep rotating the pickup clockwise until it turns on again. The engine is now statically timed at 0 DBTC. With a pencil, put a mark on the degree line on the pickup and the inside of the cone. Rotate the pickup 10 degrees CLOCKWISE and lock it down (marks are visible on the ignition pickup plate). The engine is now statically timed. Hardware installation is complete!


12. BLEEDING THE FUEL PUMP-The fuel pump may have air at this point and will require bleeding. This is accomplished by loosening the #3AN fuel line on the fuel rail and turning on the ignition switch. The pump will run and force air out. When done properly, the fuel pump will rotate with a high pitched “whirring” sound.


13. THE FINAL TEST-Now you are ready to start the engine! Turn off the ignition switch, then turn it on again after 5 seconds. The red LED will turn on. The green LED may or may not turn on, depending on the position of the engine. You should hear the fuel pump whir, then stop. Turn the throttle grip to 45 degrees with your hand, and you should hear the injectors “clicking.” This feature, which is used to prime the engine, indicates the injectors are functioning properly. Only leave the throttle in this position for around 2 seconds, then return it back to zero. Now depress the starter button, just as you would normally to start the bike. You should here it fire or even possibly start. If so, turn off the engine and perform a complete system check to verify there are no fuel or electrical problems.

Pegasus Banner



14. MAKING PFI WORK FOR YOU-Since the PFI system was designed to work on any V twin engine, you must load the proper file into the brain before testing the bike. If you are capable of doing this, proceed to section 6 to install the proper map file.

Software installation

The PFI kit comes with a base map for an 80 cubic inch engine with an Andrews EV-46 cam and a Supertrap. If you have any engine configuration other than this, you must load the proper map into the brain. This can be done either with a PDA or with a computer. We are assuming you have loaded PFICOMM onto your computer. If you haven’t you must have a computer running Windows® 98, or 2000 and a CD-ROM drive. Run the setup program to install PFICOMM our communications software.


1. Take the supplied electrical communication cable and place the RJ45 connector into the receptacle on the brain. Connect the other side to the computer serial port. If you want to use your PDA instead of a standard computer, you must use the PDA-brain cable/software available from Performancefi.

2. Again, assuming you have installed the PFI communication software supplied in the kit on your computer, start the PFI communication program, then turn on your system using the main switch. When prompted to load all brain info into your computer, reply “yes.” You can examine the contents of the brain directly, but don’t change anything at this time!


3. Because the PFI system was designed to be used on any V twin motor, the proper files that most closely fit YOUR motor must be loaded into the brain. Under the main menu, select “file” then “open.” Find a file that most closely matches your configuration. Then, again under “file” select “send file to ecu” and send. After a couple of okays and prompts, the file will be loaded into your brain (ECU). Software installation is complete!

The two mad scientist behind the Pegasus marvel, Mil Blair on the left and Dr. Stew on the right, a professor of mechanical engineering and Cal State Northridge University.

TIME TO CRANK IT UP At this point, the setup is pretty much complete. You have performed the mechanical part of the installation as well as getting the proper maps into the brain. The PFI system responds very similar to a carburetor in terms of starting/running....just better. However, it is important to understand the nature of the PFI system and just how it responds to your inputs.

Again, if you have downloaded a map that is perfect for your engine configuration, then you will be able to crank it up, and ride away! But the PFI system is just so powerful, you’ll want to take a crack at tuning your engine, even if it means just turning the knob on the brain. Remember changing those main jets and getting gas on your hands (and searching for the screws you dropped)? Those days are over.

Starting Your Engine The PFI system does not have an automatic choke and extra fuel must be introduced manually when the engine is cold or below operating temperature. This is accomplished by turning the knob on top of the brain to the “C” or choke position prior to starting. Please note the amount of extra fuel during choking can be altered (see tuning section).

You may also want to add “primer” fuel to the engine before you start it. Assuming the main switch is on and the fuel pump has stopped, by turning the throttle past the 1⁄2 point an extra spray of fuel will be introduced into the intake manifold (BE CAREFUL!! Leaving the throttle open for too long with the engine off may flood the system). A couple of quick squirts will do the trick, and it’s usually only needed when cold.

With the throttle completely closed, engage the starter button. The engine must turn over at least two times. Slowly open the throttle until the engine starts. Then let it idle at 1500 RPM until it warms up. When warm, turn the fuel knob back to the “normal” position.

Running Your Engine With the fuel knob in the “normal” position, run the bike as you normally would. Check for throttle response crispness by first rolling on the throttle, then increasing the roll rate. Note that throttle crispness can be changed (see tuning). In high gear, roll into the throttle and put the engine under load to see if it responds. Decelerate and listen for backfires.

You can use the spark plug method to see if the engine is running properly. In high gear, roll on the throttle and put the engine under load up to 5000 rpm, then pull in the clutch and kill the engine. Coast to a stop and check the plugs.

If the bike ran great but the plugs seem white, do not be alarmed...Electronic Fuel Injection systems have better fuel atomization and don’t need as much fuel to achieve power, but it you felt a “flat” spot, note the rpm at which it can fix this with a PDA or laptop. On the other hand, if the plugs appear to be sooty black, the fuel mixture is too rich.

You can then adjust the internal fuel map using a computer, PDA, or you can use the knob on top of the brain to lean the mixture. By rotating the knob counter clockwise towards “L” you can lean the mixture in 5% increments. Try one click and repeat the spark plug test. Note that you can also richen the mixture at any time by rotating the knob clockwise towards “R” to richen the mixture as well, in 5% increments.

The tuning chef
The famous Pegasus tuning chef.

Do you want to get good fuel economy on the open road? When up to cruising speed, turn the mixture knob counter clockwise towards lean (slowly, one increment at a time) to increase your gas mileage. You won’t have much power and you must be careful not to accelerate hard under this lean condition as you might damage your engine. Don’t forget to turn the knob back to the normal position when you’re done.

Watch for more on the Pegasus Nitrous controller in the near future.

Call us at: (714) 398-2360
Email us:

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Reader Comments

I have 49 pan shovel
HOW MUCH ? Money! you keep avoiding to put it out there I'm guessing $1200.?

Marcel j. Couturiaux
Apollo, Pa
Thursday, November 23, 2023
Editor Response Pegasus are no longer available. I would suggest a classic Linkert, an S&S super E or a Mikuni carb.
Hey Bandit, I'm trying to get a 147 c.i.d. Twin Cam running with this system! It's been sitting for 18 years almost complete. I need a wiring diagram to hook up all the wires coming out of the throttle body. Got the pick-up plate & trigger wheel installed and know the 3 wires to the battery. BUT, I haven't a clue on what the other colored wires go to!! Any help would be appreciated!

Doc Welbon
Bailey, CO
Thursday, October 19, 2023
Editor Response Hey Doc,

I will reach out to Mil Blair tomorrow and see if he has a wiring diagram.
I’m right here in New Haven and think you’re in Providence Rhode Island if you ever get this give me a call 203-980-1070. I'm looking to find a Pegasus fuel injection system for my FXR.

very important

Alan D'Auria
East haven conn 06512, CT
Sunday, March 12, 2023
Editor Response Actually Mil Blair is in Los Angeles.
I am building a 114ci Shovelhead with Dual plugs heads, has a 6-speed Baker BDL 3” setup and looking at a EFI setup.
The Pegasus FI has ignition in the kit which is great, could you tell me
1. Would it make the engine run smother seeing it has the 5” stroke which I understand will run a little rough due to the long stroke.
2. The positives
3. Negatives
4. Would a S&S G air cleaner fit
5. How easy is it to install
6. Whats the price without the coils and air cleaner as i already have brand new dual coils and Air cleaner.

Would be good to understand the best way to go with this setup.

Ross Mason
Gladstone , Qld, Australia
Monday, September 3, 2018
Editor Response Unfortunately Mil Blair and the Pegasus Team are out of business. I believe S&S has a fuel injection system you might look into. Let me know if you do. We might want to follow your build.
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