Kz400 generator upgrade

Wondering if anyone has swapped out a 2 phase charging system for a 3 phase one on a kz400 permanent magnet rotor type
Reason I ask is I have just rewired the bike to run battery less with a capacitor and I don’t have spark whilst kick starting only the neutral and oil lights flicker , it should work but it won’t
Connecting a battery up in place of the cap I then have a strong blue spark problem is I don’t have room to stick in a battery we’re the cap is located checked across the 2 phase winding and this reads 0.5 ohms both phases O.L when tested to ground.

I believe you will find that the KZ400 3 phase charging system uses a field coil. Assuming that is true, I don't think the field coil charging system will work without a battery. Ed

650ed wrote: I believe you will find that the KZ400 3 phase charging system uses a field coil. Assuming that is true, I don't think the field coil charging system will work without a battery. Ed

Hi
I was thinking a different model could fit like a z550 / 750 maybe that has magnet rotor

There is no 2-phase system. There is only 1-phase and 3-phase. 1-phase has two wires from the stator, 3-phase has three wires from the stator.

If yours is 1-phase, then I think you should have a permanent magnet alternator. Then you should be able to start without a battery as long as you have a capacitor where the battery would have been.

You may not know this, but when you go batteryless, you must have everything powered off except the ignition. If you have the lights on, they will drain the power before the ignition can spark. Lights act like a short until their filaments heat up. Once the bike starts, you rev it, then switch on the lights while the RPMs are high. This gives the light filaments enough time to time to heat up before the engine stops. Then it should run like normal.

If you accidentally kill the bike while riding, Remember to turn off the lights! It's easy to forget that. Or you can build a relay circuit which will automatically turn the lights off every time the motor stops. You then use a button as a trigger to turn the relay on when the bike is running.

If the regulator/rectifier has a brown wire, that must be permanently connected to the output of the reg/rec. If not, you can burn out the capacitor under certain conditions.

loudhvx wrote: There is no 2-phase system. There is only 1-phase and 3-phase. 1-phase has two wires from the stator, 3-phase has three wires from the stator.

If yours is 1-phase, then I think you should have a permanent magnet alternator. Then you should be able to start without a battery as long as you have a capacitor where the battery would have been.

You may not know this, but when you go batteryless, you must have everything powered off except the ignition. If you have the lights on, they will drain the power before the ignition can spark. Lights act like a short until their filaments heat up. Once the bike starts, you rev it, then switch on the lights while the RPMs are high. This gives the light filaments enough time to time to heat up before the engine stops. Then it should run like normal.

If you accidentally kill the bike while riding, Remember to turn off the lights! It's easy to forget that. Or you can build a relay circuit which will automatically turn the lights off every time the motor stops. You then use a button as a trigger to turn the relay on when the bike is running.

If the regulator/rectifier has a brown wire, that must be permanently connected to the output of the reg/rec. If not, you can burn out the capacitor under certain conditions.

hi loudhxv
yes it should spark with a cap but it wont the system is set up to kick on ignition only with the oil and neutral light horn and brake light on the circuit yet whilst kick starting no spark at the plugs if i connect any battery 12v to where the cap is i have strong blue spark the rotor seems to have good magnetism could the reg / rec be at fault here although it seems to check out ok .

oldblighty wrote:

loudhvx wrote: There is no 2-phase system. There is only 1-phase and 3-phase. 1-phase has two wires from the stator, 3-phase has three wires from the stator.

If yours is 1-phase, then I think you should have a permanent magnet alternator. Then you should be able to start without a battery as long as you have a capacitor where the battery would have been.

You may not know this, but when you go batteryless, you must have everything powered off except the ignition. If you have the lights on, they will drain the power before the ignition can spark. Lights act like a short until their filaments heat up. Once the bike starts, you rev it, then switch on the lights while the RPMs are high. This gives the light filaments enough time to time to heat up before the engine stops. Then it should run like normal.

If you accidentally kill the bike while riding, Remember to turn off the lights! It's easy to forget that. Or you can build a relay circuit which will automatically turn the lights off every time the motor stops. You then use a button as a trigger to turn the relay on when the bike is running.

If the regulator/rectifier has a brown wire, that must be permanently connected to the output of the reg/rec. If not, you can burn out the capacitor under certain conditions.

hi loudhxv
yes it should spark with a cap but it wont the system is set up to kick on ignition only with the oil and neutral light horn and brake light on the circuit yet whilst kick starting no spark at the plugs if i connect any battery 12v to where the cap is i have strong blue spark the rotor seems to have good magnetism could the reg / rec be at fault here although it seems to check out ok .

think i have just answered my own question il disconnect the brake light and horn to see if there is a back drain on these should it still go with having the oil and neutral light in circuit

What year and model is the bike?
Have you looked at the alternator to see what it is?
A little punctuation would go a long way too.

loudhvx wrote: What year and model is the bike?
Have you looked at the alternator to see what it is?
A little punctuation would go a long way too.

Hi loudhvx
It’s a z400b year 1979 with a permanent magnet rotor but not standard

Ok, then do you know what size capacitor you have? Capacitance should be between 5000 and 12,000 micro-farads, and the voltage spec should be 35 to 50 volts. (Higher voltage is ok too, maybe better.)

The capacitor has a polarity, and it should basically wired in place of the battery.

Like I said, the reg/rec's brown wire (if you have one) should be connected to the output of the reg/rec.

You should run a switch to make sure all lights etc. are not in the circuit when starting. The only thing that should have power is the ignition.

Is the ignition stock points and stock coil?

Maybe the charging system is not working properly. Run it with the battery and make sure you can easily get it to 14v by revving the motor.

Do you have a copy of the wiring diagram you used to wire the bike, so we can check it to make sure the charging system is wired correctly?

hi loudhvx
i just wired it up as i went along starting from the generator
the recifier has 4 wires 2 from generator plus 1 pos, 1 earth
dont have any carbs for it as yet so unable to run for an output test, just wanted to get it wired up ready prior to the final finish of the build , the ignition runs from a rotary switch the first click is wired for ignition and a feed for horn and brake light, the second switch position gives lights plus ignition, horn and brake light ,as i mentioned earlier no problem whatsoever if connected to a 12v power supply , il have to check wether the horn or the brake light it sucking juice away when not activated.
i dont know if the oil and neutral bulb (3w) each would have any effect on my plug spark problem
just checked the cap - 40v 22000 uf

I haven't tried a cap that big. My bike uses a 5000 uf, but I have a 3-phase stator.

I think you would be best off to get the bike running with a battery first. Get it properly tuned and make sure it can start on one kick. Then go to the capacitor. You can use a really small 12v scooter battery in the meantime. But using a capacitor before you know the bike is perfectly tuned could be a needless headache.

Once the bike is running perfectly, then test the charging system to make sure it is working perfectly. Then swap to a capacitor.

Hi loudhvx
Got spark with swapping out the 1 phase stater for a zzr 250 3 phase one, it was just plug and play , even the rubber wire grommet fits the 400 case exactly right with more than enough wire tails to route to the 3 phase recitifier , you are correct that the original 1 phase flywheel will work with the 3 phase stater , now have a good blue sparks even with the idiot lights connected in circuit whilst kick starting.
Glad I got this out of the way now it’s onto the final stage of the build which is the carb or carbs.