Batteryless wiring with a 2-phase alternator.

So I'm building a KZ650c into kind of a backroad burner and I'm trying to make a batteryless wiring harness which isn't so hard. My question is with a 2-phase alternator (2 wires coming out of the alternator, is that 2-phase?) what size capacitor do I need to run?? I'm using all the stock lighting and the points ignition however it will eventually be converted to Loudhvx's HEI system. Also what other things do I have to watch for while running this system?? Thanks for any help you can offer.

2 wires = single phase

I haven't done a batteryless system on a 1-phase, but I know that it's been done (by someone I know personally).

The size of the cap sort of depends on the power consumption of the bike. The HEI system is very efficient, even more so than the factory elec-ign which is more efficient than points and way more efficient than the Dyna S. Generally speaking the cap should be from 6,000 to 12,000 micro-farad (uF) and should be rated about 50v to protect against spikes. Higher uF is better since yours is a 1-phase, so I'd recommend in the 10,000 to 15,000 range.

There are a couple issues to be aware of. First you will need a dedicated switch to kill tail and headlights. Most likely the bike will not start with the lights on. High wattage lights act like a dead short before their filaments heat up. This will drain away all alternator current and prevent the cap from getting an initial charge. It takes about 1/4 to1/2 second for the lights to heat up before the capacitor will start to charge. So you have to start the bike with the lights off. After you start the bike, you give a little rev then hit the light switch. The ignition cuts out for a split second as the lights drain the cap, but since it's still turning, there is time for the lights to heat up and then the cap re-charges quickly. After the lights heat up it should run fine. See the last paragraph for converting the starter button to a light switch.

Another issue is the wiring for the reg/rec needs to be altered if it is the type with the brown sense wire on the reg. The early 650's with 1-phase systems didn't have that type so it may not be an issue for you. But for others: The problem is, that when you shut off the bike with normal wiring, the motor may have momentum. When the bike is shut off, the power to the sense line gets cut so the regulator stops regulating. But since the motor is still generating power, and none is being used, all of the electrical current goes to the cap for just a moment. This is enough to blow the cap. So the brown sense line needs to be hardwired to the power output line of the regulator/rectifier. (It is not done this way from the factory since this may slowly drain a battery, but with no battery, no problem.)

One other thing I noticed, is that it is slightly easier to stall if you are sloppy on the clutch/throttle in casual driving. The problem is the motor drops to a very low RPM and the cap drains enough to prevent spark. It's not a big issue, except that if you are in traffic, you may forget to turn the lights off and sucker will not start. For this i created a self holding relay circuit which automatically shuts off the lights when the motor stops. The relay is actually triggered by the now un-needed starter button. This also allows you to use the starter button as the light switch thus eliminating the need for another switch. I can post details if needed, but I think I have a thread on it somewhere.

you need to write a book one day Lou,youre a genius!

Hey, thanks Plumm!

Becker, I posted the diagram for my batteryless bike on page 4 of this thread:
kzrider.com/index.php?option=com_kunena&...limitstart=60#259190

I forgot to mention, I put a 5 amp fuse to the cap in case the cap shorts, but I think it's unnecessary. I also keep a spare cap mounted and ready by moving one wire.

Also, I'm running a cap-fault or spike detector I designed, but after one season there hasn't been any problem. Here is the design for the spike detector in case anyone is interested.
www.geocities.com/loudgpz/GPZspikeDetector.html

Thanks for all the help lou thats exactly what I was looking for. The first time I saw the maggot tail on your bike I had an intensley nauseous feeling that was quickly replaced witha "that is the coolest tail I've ever seen"
feeling. Sick, truly sick. I love it.

Thanks Becker! I had to bring him in for the winter, though.

Let me know how the batterylessness goes for you.