Fuel Regulator -- Kawasaki ZX750E
The DFI control unit for all ZX750E models, with the exception of
some US models (E2) has race version specifications program in its microcomputer.
So that the customer who desires to tune his DFI system for race use can
modify it.. do it, fuel has changed over the years,
costs are only some 5-10 euro, makes it very easy to adjust fuel settings.
Even if you do not want to tune your bike, you'd preserve it by modifying it like this.
This includes saving your Hitachi HT10B, a lean mixture will become hotter than a good mixture.
But i know somebody who can overhaul them for a fair price, if you don't care that much....what I'm saying is, run to the store and save yourself a lot of money, trouble etc.
If youre bike is suffering from sudden dip in power when boost comes on (holding back for a split second), or if you have modified the actuator resulting in a ignition kill at high boost: cutting the wire will already solve half your problem, because it stops doing that.
Modification for Race use
(1) Remove the vinyl taping around the wiring harness which
branches from the DFI system wiring harness and leads to the
air temperature sensor.(the hard spot where it doesn't bend)
this is what you are looking for, it's taped in with the AIR TEMP SENSOR
The bottompicture on this page shows some red tape near the sensor, that's where it's hooked up.
cut the wires loose, and weld yourself an 'fuel-amplifier', from parts seen in this picture.
To built the fuelregulator, you need the following: (get it at your local electronics shop)
- a weldingtool and some solder.
- a potentiometer with the range 0-5 kOhm (max 4 watt) (if you check it you will see it goes to 5.2/5.3 probably)
- a small plastic box to wrap it in, and a turning knob
- 2 pieces of electrical wire, makes it easy to install the thing, at least 30 cm (1 foot)
- 4 cable connectors
- some selfamalgamating tape (boatshops) or other insulating tape
- a drill, to make holes in the box
- a saw, to cut away the excess stem of the potentiometer if wanted)
some siliconkit (do-it-yourself shop) to fill up the box against vibrations and water
(don't use that much of the stuff the potentiometer doesn't work anymore)
good, weld the wires to the potmeter, drill 2 holes in the box,
put the potmeter in there and feed the wires out, fill the box (partly) with silicone goo and close the box.
make the cable connectors to the cut wires on the bike and the wires from the box you just made, and connect the thing.
The endresult should look something like this:
Before you attach the wires to the wiring loom of the bike, use a multimeter and set the potmeter to a value of 4 kOhm,
it's probably running rich, but it's better to start with than with running lean.
Then start the engine and go for a testride (or for starters: dynajettesting), if your plugs are black after a good warm-up and 30 minute ride, you have to lower the valueby 0.1kOhm. Start her up again, drive and check again.
I've done readjustments throughout a year period, if you want to get it perfect, you need to always use the same fuel and some 'feeling' in what runs smoothest.
If you find the correct setting,
replace the found value with a resistor of that value to prevent the settings to change while riding
(or tape the knob to the housing, like I did)
Beware that every little change you make in the setting of the resistor is calculated through in the ammount fuel it gets by this rule:
5R
K=----------+0.56
4(R+5))
Where R= Resistance in kilo-ohms (R) is between 1.2 and 5.2)
K = a given value between 0.80 (80% of fuel delivery) and 1.20 (120% of fuel delivery)
Ok, time to start your bike.
BEWARE, you can change settings while running, they only come into effect after a restart.
