In the 60's there was a growing number of bikers who were trying to find ways to tune their bikes and get the most performance from their cafe racers - one way was to fit a 'Wal Phillips' fuel injector - although not strictly 'fuel-injectors' these simple devices did improve performance - there was even a review of the mpg and mph gains when a small bore fuel injector was fitted to a G2 (250cc) Matchless.  I think that this review was in motorcycle mechanics - either way, the published improvements were an improvement (4% - 8%) over the standard Amal carb.   After reading about this many years ago I recently was reminded about this when I saw a couple for sale on ebay - I got to thinking what would be the improvement if I fitted a pair to a G15CSR? ....Hmmm? An interesting idea.   

One thing that I should bear in mind though, is the reason why these fuel injectors aren't sold any more.  There is no float bowl and thus no 'automatic' means to turn the fuel flow off when the engine stops - This loosely means that you have turn the pet tap off very quickly or you run the risk of a fiery inferno! (ouch!).  (The fire-risk was one of the reasons that they were withdrawn from sale from many suppliers- big liability!).  Also in a manner very similar to the Amal GP carbs, I have heard that it's tricky, if not impossible, to obtain a decent 'idle' with a Wal Phillips injector fitted. 

Well, back on track - I was lucky enough to get a scan from a Andrew Staley, in  Hexham, Northumberland.  What a great guy!  Even scanned the instructions provided (and signed) by the late Wal Phillips himself on how to set up a pair on a twin engined bike  (Triumph Twin).  Perfect!  Thanks Andrew!

(Feb 11, 04)  I've just discovered a slight complication to this project - not only were the fuel injectors available in SIX different bore sizes, but they were also available pre-fitted with a multitude of different sized 'main jets' or, more accurately, 'fuel metering valves' (including a series of large jets especially for Methanol - useless for anything else).  Since the main jet is fixed into the unit - there is a strong possibility that the Fuel Injector that you buy on Ebay will NOT be correct for the application that you need it for.  Doh!  BE WARNED - Based on the sizes available (1inch bore through 1.5 inch bore) - and the 'fitted' jets - chances alone --  buying 'blind' without knowing bore/jet size on items on ebay, the odds that it will actually work on your bike are about 60:1 against!  Ouch!  This can get to be a very expensive collection of paperweights! 

IF YOU PLAN ON FITTING ONE TO YOUR BIKE, MAKE SURE YOU ASK THE SELLER FOR THE BORE & JET INFORMATION - otherwise prepare to be disappointed.

Follow-up  I received this brilliant series of notes via email from "Victory" - Fantastic!

Thanks, appreciate the info.
Some ideas you may wish to consider:
1. the fuel pressure (gravity X height difference X weight of fuel in bowl) can be made "normal" by using a float bowl, so that the height and weight are constant and won't vary with amount of fuel in the tank (at least, until it's almost empty).
2. my ideal candidate is a remote bowl (or 2) from an SU with Rivera (larger replacement) needle.
3. petcock: use vacuum tap type as used on late Harley or older Kawasaki (My 1972 H2 had one), so you don't have to turn it off.
4. I show 8 sizes: 1", 1-1/16", 1-1/8", 1-3/16", 1-1/4", 1-3/8", 1-1/2", 1-5/8" in an ad.
5. idle quality: my thought was to tap into the manifold right after the body (so as not to modify the WP itself) and install a small fitting with a needle valve and a hose going to the air cleaner backing plate. This way, you can meter air into the motor directly (similar to an IAS on EFI), and it gets air from a filtered source.
6. here's some copy I picked up from the net - please don't distribute it as I don't know who the author is, or how reliable, but it may help:
I WILL REMOVE THIS IF COPYRIGHTED? IT IS JUST TOO INTERESTING TO KEEP "SECRET" PLEASE CONTACT IF ANY OBJECTIONS (Rick Mann)
"Starting tips:
Turn the fuel on at the last possible moment, and turn engine over by kicking as normal.

Hold the throttle steadily, just a little open and blip the throttle on and off as soon as the engine gets running. To stop the engine, turn fuel tap off. (Sounds like normal practice? RM)

Should the engine not fire right away it may flood up with fuel, so turn the fuel tap off and kick the engine over with the throttle wide open to clear it. Should the engine burst into life now, quickly turn on the fuel and try to keep it running by blipping the throttle on and off while the bottom end (or first half) of the throttle range is adjusted. Always adjust the bottom end setting with the engine running. (Again nothing unusual here - RM) 

Flat spot. Delayed response to the throttle movemement or a flat spot signifies a weak mixture. This may be rectified by taking the connecting link down the threaded jet lever, having the lock nuts already finger tight only so that the adjustment may be made with the engine running.

Heavy smoke. Uneven running (eight-stroking) plus black or heavy blue smoke form the exhaust signifies an over rich mixture. This may be corrected by adjustment up the threaded lever. This allows the jet, which is in effect a jet-sized petrol tap, to shut off a little in relation to the butterfly, thus weakening the mixture.
Tuning the top half

The above adjustments will have been made with the throttle not more than half open, so you have tuned the bottom half. Having got the bottom end reasonably clean, thighten the lock nut - always the same one - and start on the upper half.
With the engine in neutral, quickly open the throttle at last as the engine will take it and listen as the revs mount right through the range. At full revs in neutral gear the exhaust note wants to change from clean two-stroking to a slightly uneven rich sound.
Should this note come in earlier up the range and be accompanied by excessive blue smoke, the top end is too rich.
Adjust the top end weaker by screwing down the throttle stop screw one turn and lengthening the link until the butterfly is restored to its fully-open position. This will weaken the mixture right through the range, and two or three turns down the threaded lever will be needed right away to correct the bottom end weakness.
Restart, re-tune the bottom end and check the full throttle sound again. When the required result has been obtained - that little uneven or blabbing palse of uneven at full revs - it is in order to go out on the road and in due course carry out the final top and tuning adjustment to the point of a plug check.
Have a short burst of full throttle in third or top gear. Switch off the fuel and coast to a standstill. Examine the plug points. White, dry plug condition means weak mixture and a risk of engine seizure. Light or full brown colour is fine. Black means too rich.

Fitting & Tuning instructions for the Wal Phillips fuel injector
Fitting notes: To allow clearance for JET LEVER it is sometimes necessary to file the RIGHT HAND (offside) nut, also with some machines the stud may have to be shortened. To avoid distortion of the flange ensure that both nuts are tightened equally. (As you would for an Amal carb RM) Couple up the original throttle cable, not forgetting to place the spring between the cable stop and lever, and then connect plastic petrol feed pipe. The injector is now ready for test.   (Remember the NEW kits never came with a spring - so you may have to find one - RM)  

Starting the machine:
1. Open petrol tap.
2. Kick over the engine as normal.
3. Should the engine flood, switch off petrol, open the throttle wide and kick over the engine a few times.
4. Always stop the engine by turning off the petrol, leaving the injector dry for instant starting.

The Phillips Fuel Injector is a very simple design. The jet assembly is in effect a petrol tap. The butterfly is in effect an air tap. The levers are arranged so that the tuning of the first half of the throttle - taking the link down the long threaded lever for richer, or up for weaker - does not upset the basic full open setting. The second half of the throttle travel-top end-tuning is controlled by the throttle stop - say by one turn - and then lengthening the connecting link to bring the butterfly back again to the fully open position. This will weaken the mixture right down through the range, and call for a richening of the first half of throttle travel (bottom end). Tune the bottom end with the engine running, and when a clean pickup is obtained (lagging response and spitting back means too weak. Eight stroking and black smoke means too rich) open the throttle fully very quickly and watch the exhaust. Should black smoke appear as the revs mount well up the range the top end is too rich. Adjust weaker as described (not forgetting to reset bottom end) until black smoke has cleared. Then road test and finally tune top end to plug reading.
The idling stop should be set and at the same time the throttle cable must be adjusted precisely without slack, otherwise the throttle return spring will overcome the spring in the link thimble, and allow the jet to shut right off, so stalling the engine.
Bias on the side of vertical turns (on one unit) may be located by slackering off one side flange nut (????Huh?  RM) - with the other side not fully tight, and pushing the unit over to make an air leak. If this is done with the engine running at near idle and the bad cylinder begins to fire this is the rich side. Now remove unit and make a small air leak that side, by cutting a little groove in a fibre manifold gasket (which may be fitted if one is not already there). All this is well worthwhile to get the superb instant response, and clear cut power gain that the injector will give.(Wow! sounds like witchcraft rather than science! RM - is this a twin with a single injector?)

Twin injectors: Fit separate pipe and tap to each unit so that after starting up, one side may be switched off whilst the other is tuned to run clear, right up the range. Then switch over to the first side and tune it likewise. Level butterflies with cable and adjusters. Tune top-end to plug readings.
Basic setting: Your injector is adjusted to a basic setting and the clamps should not be disturbed. If, however, by accident the clamps are moved use the following procedure:
1. Insert a ..... drill shank through the fuel feed hole, so that it is visible in the injector bore. This lines up jet in open position.
2. The left hand clamped lever must be hard against the throttle stop screw and the jet block.
3. The butterfly must be in the horizontal fully open position. Adjustment is carried out by altering the length of the connecting link
4. Arrange that connecting link is at approximately right angle to threaded lever when is fully open position. NO END FLOAT at jet spindle.
    There had to be throttle control so he made a simple butterfly and as it seemed pretty obvious that the more the throttle was opened the more petrol the engine would take he linked butterfly and petrol cock together.
    The fuel goes in the brass pipe on top of the casting. Inside the casting is a bar with a hole through it. As the throttle is opened, the hole in the casting and the bar line up, drawing the fuel in. The second picture shows the slide at half throttle."