TOPIC:

Spark plugs are all new, they were black-ish when the engine was taken apart. Last time the engine ran it misfired really badly and there was strong smell of gas of exhaust so it was propably running really rich.
I wonder what keeps burning Darlington transistors?
This Kawasaki is not mine, it´s my neighbours, he is a senior citizen and has owned this bike over 15 years. I´m just a happy helper, co-mechanic, googler, and a translator.
There has been some problems with rectifier/regulator last year and it has been replaced. If I remember correctly the charging voltage was a little low (between 12-13volts), after regulator was replaced it went to steady 13,8volts. Other electrical thingy was when fan temp sensor died and when driving in city areas, low speed, fan just kept going till battery was empty.
After yesterdays disappointment with another DFI box, we will re-check the timing and sparks one more time and then focus on the injectors.

I wonder if that replaced temp sensor next to thermostat (i think it is for fuel injection) affects the EFI cold start? Sensor is from Toyota Diesel engine. I don´t know if the resistance value is correct.

You mentioned the regulator rectifier problem last year. Although there doesn't see to be a common understanding of "how" it fails, the common reoccurring observation is that the stator is found burnt out (short between the phases) and an over voltage situation. The regulator opens the circuit between the stator windings and the diodes in the rectifier to control voltage and the transistors doing that are subject to high loads as they open and close. It's unfortunate that Kawasaki didn't opt for an alternator with a control rotor voltage similar to the Honda alternator. It's a cost thing.

The Darlington transistors in this CDI control box are running at a maximum current draw with these coils. If the resistance in the primary ignition drops below 2.7 ohms, the Darlington transistors will be subject to higher current than they are designed to handle. Some members have pushed the limits of the Darlington's by running aftermarket coils and removing the ballast resistor and got away with it. In your case, you state the bike has been in your neighbor's possession for 15 years so I'm sure you know what if any modifications have been done to the ignition. What you may not know is if the coils develop low resistance when warm which could be caused by a breakdown in the insulation of the copper wire in the primary windings. Something to think about.

The engine temperature sensor is required to meet certain requirements as per page 3-6 in the zn1300 manual but I suspect your issues are at this point not related to the engine temp sensor. It is a feedback signal that the DFI computer needs to consider and will have an effect on overall performance but right now you have a no run condition. You will need to check the readings of the engine temp sensor down the road but not right now.

The DFI system relies on 2 conditions and does not monitor for any changes.
First- the fuel flow and fuel pressure must be a measured pressure of 33-36 psi at all throttle positions.
Second- All of the fuel injectors must remain closed and leak free unless energized by the DFI controller.
If either of these conditions are not met, the fuel injection system cannot work as designed. So you need to confirm these 2 items before continuing. I'm betting the bank on leaking faulty injectors or a over pressure situation with the fuel pressure regulator.
The fact that the DFI box is not flashing any codes tells me that all of the input signals have been checked and no faults are found and being reported by the DFI box so as far as I'm concerned at this point, there would appear to be no reason to suspect the DFI circuitry. BUT the DFI assumes the fuel pressure and injectors are functioning so it is not reporting a problem since it's not measuring these parameters. If down the road once you have this bike running again and you find the spark plugs black, then you would need to start checking some of the adjustments like the throttle position sensor and in your case, the engine temp sensor since it's been changed out for a non standard sensor.
On a really good DFI system similar to the automotive systems of today, an open loop system which has O2 monitoring can run at the desired 14:1 fuel air ratio all the time and the spark plugs should be burning almost white. The Kawasaki DFI is a closed loop system meaning that the fuel map is fixed and only compensates for air temp, engine temp, air pressure, throttle position and energizes the injectors based on these limited parameters so in order to guarantee not to run in a lean condition and burn holes in the piston, the fuel map is set to run slightly richer than the 14:1 ratio you would like to see. So you should expect the spark plugs to be running a very light brown color . Carburetor engines don't compensate for air temp or barometric pressure so they must be run even richer to guarantee a not lean condition so if set up right, the spark plugs should be running a medium chocolate brown and probably dusty appearance.
True open loop systems do not have choke butterflies with fast idle cams on the throttle bodies. That's a dead giveaway that the fuel injection system is a closed loop system. Also open loop systems have idle air control valves and hold the engine idle at a fixed rpm during warm up and operating temperatures.

Those are my thoughts for now. Let us know what you find please and thanks for sharing this experience with all of us. It's an experience we can all learn from.

KB

Injectors are working and there is no leaks. I listened them, one by one, with stetoscope and they all keep that solid tapping sound when engine cranks.
Fuel pressure is around 3 kilos per cm3 (???).
It looks we have to give up. It has been an interesting six months but as we still don't even know what the main problem is, fixing it seems impossible.

Tuomas wrote: Injectors are working and there is no leaks. I listened them, one by one, with stetoscope and they all keep that solid tapping sound when engine cranks.
Fuel pressure is around 3 kilos per cm3 (???).
It looks we have to give up. It has been an interesting six months but as we still don't even know what the main problem is, fixing it seems impossible.

3 kilograms /cm2 = 42 psi which is a little high but then your gauge is probably not calibrated so you're in the ball park.
After pressurizing the fuel system, did you shut off the key and watch the pressure gauge?? Did it drop?
Are you sure you have the plug wires on the right plugs?? Sometimes when focused on one problem you make mistakes that complicate the primary issue. Just saying. for me the easiest way to confirm this is to have all of the plugs out and attached to the plug wires and crank the engine over . when looking at the left side of the motor, the 3 plugs should fire 3 - 2 - 1 - 3 - 2- 1. And on the right side 4-5 -6 4-5-6 Sometimes you can mix up 2 and 3 or 3 and 4 or 4 and 5 by mistake if the wires are not marked and are the same length. It's the stupid little shit that will really screw things up and when you get it all figured out you'll be upset that you didn't think of this first.
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You have spark and you have fuel. What's missing ? Timing of the event or compression.

Have you check the valve clearances?? If they are running on the tight side of the clearance it's a problem. These camshafts are really lazy to get moving and if the clearances are tight, the actual valve timing can climb up to 300 degrees of duration really fast. Check the clearances and adjust to the fat side. .006 - .007" on the intakes and .008" - .010" on the exhaust.

you 2 have been at it for 6 months and you want to throw in the towel? Hell no !! What ever this is causing you grief, it's something really simple. You just haven't found it yet.
'I've had problems like this and sometimes the best thing to do is walk away from them for a day and clear your head. I learned this a long time ago. If you keep beating yourself up you'll never get anywhere. Take a big breath and take a day off and just think this issue through.

Hi
Just have to ask, even if it is a simple question. Have you checked the kill switch for corrosion? It’s sounds like it’s off all the time

I had to go back and reread your initial post to try and help you out here.

You mentioned that the engine was sputtering and running rich just before it died. You check things out and found a bad tensioner roller so you replaced it and the timing chain. Did you check to see if there was any bent valves. If you bent some valves you have your answer.