Running without lights or battery

[traderyoda]

I squeezed the points/condenser over on the left bottom of the schematic.

The problem with Rickmans is there's very little space on a Metisse frame to stuff anything. On other machines I've stuffed Tympanium units and supercaps in the airbox, but this machine has a very small airbox (much the same as the B441 Metisse) made of compound curves - no way to hide anything in there.

I did think about the nerve needed to flick that switch, which on this machine is between the seat and tank (where the oil fill would be on a MkIV frame). I can only imagine being the middle of the desert, having a plug load up, and reaching for it.

I'm thinking NiMH vs a supercap mainly based on current. Without any extra electronics, a NiMH pack will output around an amp of current. The field windings in the dynamo are 1.7ohm and I'd fear that a cap might dump in a ton of current and possibly burn up the coils. I don't know how much field energy it takes to fire up the motor. That'll take some experimentation down the road. I'll embed a tiny plug in the harness wired at 16-gauge so I can sort out the proper battery solution later. I have tons of NiMH, Li-ion, and LiFePO4 batteries lying around in the shop so I can play around with type and number of cells to find the best solution.

Were this a later model engine I would have found a magdyno vs this old style field coil unit. That's another option... I bet a later model magdyno would bolt right up and still be MZ ISDT.

[breakwellmz]

My old 250Supa Five had an `emergency ignition` position for starting when the battery was flat would yours work the same way without a battery? It does seems odd to have to have a battery fitted to a bike like yours.

[Puffs]

Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.

[traderyoda]

Thinking about that, another comment: why is your battery on DF, bypassing that resistor? Why not just do away with that DF connection?

DF (I assume "F" means "field) to D- is what the MZ manual shows as power going into the field coils from the battery. I could certainly hook the battery to the D+ and D- connections. A 4-cell NiMH pack is 6V and would put a steady 1 amp or so through the field coils. Going to DF+ and D- with the same battery looks to me like over 3 amps going to the field coils. Since the field strength is directly proportional to the current the field would be roughly 3X stronger. Maybe that's what it'll take to get a strong spark... guess I'll find out. I don't want to overload the field coils and damage anything so I'll limit the current and see what I get. But if my math is right, MZ didn't seem to have any issue dumping 3+ amps into the field coils to get things humming. I'm cautious because I burned out an old airplane generator by flashing it with too much current. 1.7 ohms isn't much resistance.

Regarding supercaps, the ones I use have no issue cranking out gobs of current. Trying them here I'd certainly use a current limiter.

[Puffs]

Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.

[traderyoda]

It'll take some experimentation to establish a strong enough field to get it started. I think initially I'll use my DC power supply to gradually step up the current until I get a decent spark and then try starting. I have no experience with this motor or the side-float carb so I anticipate a slow learning curve. But I'll get it running and keep the forum posted.

Thanks all for your fantastic support!

[Puffs]

Well, thank you for this interesting topic & showing this most interesting bike!
Enjoy riding it!

[traderyoda]

I love a good challenge and this project has it in spades.

I did install the dynamo and wired it roughly to see what I would get. I made a few errors in wiring and quickly sorted that. Result - nice crisp spark. I have a quick disconnect in the loop and hung a small battery pack on the circuit for about 10 minutes and that's all that was needed to energize the field coils. I doubt the battery needs to sit there at all really - just hook it up and kick.

I did update the diagram to correct my goofs.

Thanks to everyone for the help!

MZ Wiring Diagram_v2.pdf

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