powerdynamo electronic ignition - AC or DC?

I'm ready to order my powerdynamo electronic ignition. There are two versions AC or DC.

To get my plate in MI I am required to have:
high/low beam headlight
brake/tail light
horn

Turn signals would be nice but not necessary.

I can make due with a squeeze bulb type horn if I have to
I don't really want to have a battery but I guess I could tuck a small lithium one in somewhere as a last resort if there is no other way to do this.

So, the question is should I get the AC or DC version?

Will the AC allow me to set it up with high/low beam switch? are there horns that will function with AC? turn signals?

Would the DC be a better choice? supposedly everything would function without the battery but the lights would be very dim if the bike were idling, would there be any other problems?

Anyone else have the powerdynamo ignition? which version? Any advice would be greatly appreciated.

i am wondering this as well...

Everything can run off AC but the horn and the flasher relay have to be AC compatible. The advantage of DC is first your lights don't dim at idle and second, providing you have juice in the battery, you can test everything works without having to run the engine. The downside is that batteries die if not charged regularly. It's one more thing to maintain.

You can have high / low headlight with AC.

I have AC but hope to convert to DC at some point.

Regards
Lucien.

The DC voltage limiter / rectifier is bigger in the size.
When you not needed indicators it´s better/easier to choose the AC ignition kit ( the parts are smaller in size, you have more place under the tank for mounting ).
When indicators really needed, you have only one choice, and this is to take the DC system.
All other pros and cons was good described by "White Husky".

I have also in all my Huskys the powerdynamo systems and this works great.

If you have any asks, write a email ( or open there a case ) to powerdynamo.
The chief there ( it´s named EDGAR ) can answer you in english language.

regards, Bernd

Thanks, after considering the responses here and talking to a couple other people today, I ordered the AC kit. I also ordered a wire harness from Procycle complete with all the little parts and switches to make this work, including a horn and flasher unit that are AC compatible. I spoke with the guy there, explained what I was doing, asked a bunch of questions and he assured me this would all function properly. I can live with the lights dimming a bit when idling or using the turn signals. I'll post here again when I finish the project, it may be awhile since I need to save up some more $$$ to buy the lights themselves.

keep us updated of the powerdynamo install and the light kit..hope it works well!

I got my powerdynamo kit complete with easy step by step instructions, which I read thru only to discover I need to know how much to advance the spark BTDC. I figured the instructions would tell me this, but it says "consult you manual" which I did and found it calls for 20 degrees BTDC (I also found that the previous owner had marked 22 degrees on the flywheel for some reason) Anyway, I only know how to find TDC with a depth gauge in the spark plug hole, measuring mm of piston travel BTDC rather than degree of rotation. I don't have any sort of tool to measure degrees or even know how to do this... so how do I convert 20 degrees (or 22 if I go by what it was set at previously) to mm? Is it ok to do it with a depth gauge this way? Anyone know the timing setting in mm for a 1974 WR250?

I would have thought some simple maths would give you the answer. Take the stroke (in mm's) from TDC to BDC and divide by 180. That will give you piston movement deg/mm. Degree discs are cheap to buy, or you can make your own. I use both as a double check. You can buy or borrow a dial gauge to be super accurate with the measurement down from TDC.
Having just done the 390WR with an Electrex World unit, my book says 2.18mm from TDC, I think the 250's from the 77/78 era were 2.45mm. Not sure about the older models though.
Hope this is of some use.

If it wasn't for the connecting rod business it would be half stroke*sin of 20 degrees. I would just measure the circumfrence of the rotor then do a ratio of 20/360. Someone probably has created a calculator to do what you want. If you use a timing light that clips around the plug wire then you can be pretty sure the spark actually goes off where you want.
http://www.frannyk.addr.com/cafehusky/timing.wood.protractor.JPG

If the spark plug hole is not totally vertical then that needs be factored in as well to be perfect.

Povide the stroke and rod length then it is just some trigonometry of two right triangles. At least at first analysis. If the piston pin is offset then more complex to be totally accurate.

Look in ebay there should be plenty
EG http://www.ebay.co.uk/itm/Motorcycl...pt=UK_Motorcycle_Parts_13&hash=item3cbcb9712e

Thanks for the help. I hope this helps others too, I see there are a couple other people on here doing this same procedure. I printed a degree wheel printed out from online, and used an old calipers with a depth gauge down the spark plug hole (holding it steady with clamps) I ended up with 2.75mm of piston travel BTDC. This was at between 20 and 22 degrees advance using the degree wheel, I am not sure exactly because the piston pauses for a few degrees at the top. the manual says 20 degrees advance, it was set at 22 degrees by the former owner so I figure anywhere in there is ok. I have not finished the wiring yet so have not yet started the bike... I'm going to start a new thread, since now I am on to the wiring part and am in need of some additional advice.

Hey, you can look here for your specs if you hadn't set the timing yet:

http://www.yourhusky.com/files/MK-ML_workshop_manual.pdf

Also, take a look at my as I just installed an MZB on a 73 450wr.

http://www.cafehusky.com/threads/1973-ignition-450wr.32970/

By the way, what was the deciding factor that made you choose the AC system? I chose the DC system for my 450wr as I wanted the most lighting wattage output available.

In another thread I posted a link where this guy Matt does the MZB install, he did use the A/C system and it did dim at idle a little bit. But, it brightened right up when reved just a little above idle.
You can find that in this thread:
http://www.cafehusky.com/threads/headlight-for-1973.67897/

If you've already completed you set-up, how did it come out? Also, do you have a list of parts with part numbers on the A/C compatible stuff you used?

thanks,
Mark

I've been following your thread. Thanks for the workshop manual, I found the magic number I was looking for... looks like I advanced it about 1 degree more than the called for 20, but I was happy with the way it ran beforehand (with 22 degree advanced spark) I put the flywheel back on so I'm not changing it now. Speaking of putting the flywheel back on, I discovered my torque wrench only works to tighten in the normal direction, this is a reverse thread nut. I hope my elbow is calibrated enough that it is tight. I also only gave it light taps to set it after reading all those warnings in the directions about making sure the magnets do not get jarred loose. I have not started it yet as I'm still working on the wiring, to install the headlight I need to install the fork ears, so I got to take off the fork tubes, might as well change those leaky seals while I'm at it... this project is snowballing so it may be awhile before I get to testing it.

As for choosing the AC system, I talked to the guy at ProCycle https://www.procycle.us/dskits/dskit.htm I got the standard AC dualsport kit minus any lights. Options and part numbers all there. Give them a call, they answered lots of questions for me. They sell kits for both AC and DC, the AC wiring sounded much simpler, and I think that is a good thing. I can live with the headlights dimming at idle, I figure they will be at least as bright as a 6v system even at their lowest. To be honest, the thing that really pushed me towards the AC was asking my dad, his advise: the DC is likely better system, but knowing me and my minimalist taste in vehicles (I used to drive a '62 Land Rover, should have never sold it) he advised going with the AC as well.

So, where are you going to put your battery?

did you lap the flywheel to the crank stub? that is usually the cause for a sheared key or loose flywheel. especially when installing a different flywheel

I am not installing a battery. Going with the DC just makes it battery capable...but not necessary.

yes, with valve lapping compound

If you can not find an AC horn (they can be hard to find but do exist), you can still use a DC one if you either buy a bridge rectifier from an electronics store or 4 diodes and then wire them in configuration of a rectifier. You can do this after AC regulation. I have done this before and it does work. How well depends on the stator output and engine rpm. You can improve the sound output of horn a little more by connecting a small electrolytic capacitor after the rectifer/diodes to act as a filter to get more smooth DC power. You can also use this same principle for turn signals. It will work best if you use LED globes though which draw little current and the rectififcation losses after you have already regulated to 12v AC wont really matter at all. Horn/blinkers/brake light are all intermittent use anyway. For LED turn signals you need to use a flasher relay that is designed for LED turn signals.

So yes you could do it all with an AC system and no battery but you will just need to add a bridge rectifier before the DC component you want to use. Also if you are using the frame as earth for AC, make sure you keep the DC earth/DC negative above or floated from the chassis AC earth. You can not have the AC and DC earths both grounded to the frame. So in the case of powering a horn, you will have the AC power wire going to one AC terminal of the rectifier, then the other AC terminal shall be grounded to chassis earth, then you feed the negative (-) and positive (+) terminals from the rectifier straight to horn.

12 volt AC horns are fairly plentiful over here. Less than £10 delivered. Just find your nearest Vespa or Lambretta enthusiast.