There is an urban fantasy series called "The Rivers of London" series after the first book (or "Peter Grant"-series after the main character) and magic interferes with (in the sense of completely fries) more complicated electronics there, so his master (the last fully qualified wizard of Great Britain) also drives an old Jaguar that is all-mechanical and therefore magic-proof. Very entertaining series with lots of references to current pop culture.

Edit: https://en.wikipedia.org/wiki/Jaguar_Mark_2#Portrayal_in_med...

Sounds like Battlestar'ing your transportation. A very popular modification scene in the car world.

I have converted modern cars to points and carbs, its not that difficult. No reason you couldnt drive any car with some motorcycle carburetturs clamped to the intake runners. Hardest part is spinning the rotor and remembering how to set your points. Never drive-by-wire cars will need a throttle cable, and a manual transmission is the only electronics-free option. I have heard a simple mechanical relay logic system can control many autos, but have never tried.

That reminds me quantum bogodynamics:

http://www.catb.org/jargon/html/Q/quantum-bogodynamics.html

Sounds very similar to "The Dresden Files". The main character is forced to drive around in an old car, since his magic interferes with electronics.

That poor car... It was almost a character of the series and it was always getting the worst end of things. I would drive a beetle if I didn't know it would kill me in an accident. One almost killed my dad.

Yes, but Peter Grant drives a Ford Asbo (Ford Focus ST), which presumably has electronics. He just needs to remember not to do magic while driving.

Hogwarts interferes with modern technology too. :)

> I realized at one point that it was probably EMP-proof

The ignition coil will probably not survive an EMP event, so the bike will not run.

However, it should be pretty straight forward to wind a new ignition coil if you ever find yourself in a post-nuclear situation.

It can probably survive. It is just a coil, and a capacitor across the contacts. Diode rectifier in the alternator might be the weakest point.

It could be a magneto as well, which is more finicky to tune, but still mechanically simple and robust.

That bike is way too old for ignition coils, it almost certainly has a distributor, which could be mechanically rotated.

One cylinder engine has no distributor, but AFAIK coil is still needed. Where do you get high voltage for ignition from?

From a magneto, but AFAIK those were obsolete well before the seventies.

I hope I am not confusing things but as far as I know there is still a coil if you have a distributor.

Yes, you still need an ignition source. The OP is confusing the distributor with individual coils found on modern engines.

A distributor is only there to distribute the spark to the cylinders. On modern engines the distributor has been replaced by individual coils (on per cylinder).

Well, sometimes one coil for each pair of cylinders. I'm not aware of any motorcycle that had a distributor though.

All gasoline engines have a spark source. A magneto, a distributor/coil setup, or a transistorized driver/coil setup in the case of fuel injected bikes. Nearly all bikes from 1920-1990 have a distributor. The differince is that it often runs off, or is part, the stator (generator coil), making it appear to not exist. Just follow the plug wire.

That's simply not true. Every motorcycle that I am aware of (except the old ones with a magneto) has spark plug wires that go directly from a coil, sometimes one per cylinder, sometimes one (with two outputs) for every two cylinders, to the spark plug. They do not go through a distributor. The low voltage wires come from either an electronic module or a set of points (typically one set of points for each coil) which are mounted to one of the crankcase covers, not in a distributor.

And while the ignition cam may or may not be near the alternator or generator, it has nothing to do with it functionally.

Interesting, after some research I find that a few very old motorcycles - Indians and Ariels - did have distributors. But these are a tiny minority as compared to all the Harleys and British and Japanese bikes in the world.

Also, I forgot that some old Harleys have the points in a housing sticking up above the crankcase. It's debatable if this should be called a distributor though, since the spark plug wires don't go anywhere near it.

What determines the ignition timing without distributor?

You can move the points just like you'd rotate a distributor. One set of points drives one coil which provides ignition for two cylinders, one which is firing (near the end of its compression stroke) and the other non-firing (near the end of its exhaust stroke). For a four-cylinder engine, two sets of points and two ignition coils are used.

This setup is even used on modern-ish vehicles, where two transistors drive two coils to run four cylinders.

Sorry. What do you mean with points? On my old car the distributor also had a vacuum line that would adjust ignition depending on revs.

If your car has points-based ignition, you'll find them in your distributor underneath the rotor. They're switch contact points or breaker points or whatever you want to call them, that are driven by a cam on the distributor shaft. They're closed most of the time, allowing current to pass through the primary side of the ignition coil. When they open, the ignition coil field collapses and you get spark out of the secondary side.

Unless your car is very old, chances are that you have a more reliable reluctor-based ignition, where instead of points you have a magnetic pickup that's triggered by a toothed wheel on the distributor shaft. That pickup drives an ignitor (which may also be inside the distributor, or it might be a separate module) which generates the high current input to the ignition coil primary.

You can twist the distributor to change your base timing, plus you have the vacuum mechanism that moves the points or magnetic pickup to adjust timing according to manifold vacuum, and it probably also has sprung weights that swing out as rpm increases, which moves the cam or reluctor wheel to advance timing.

The actual distribution part of the distributor consists of the rotor and terminals on the cap. That's what routes high voltage from the coil out to each spark plug.

On an old motorcycle, you just have the points (one set for each coil for each pair of cylinders as described above) without the distributor cap and rotor part. You can move the points around the cam to adjust base timing, and you might have springs and weights to advance timing as rpm increases. I don't think vacuum advance was nearly as common on bikes as it was on cars.

Thanks! This makes me almost miss the “good old” days when I worked on my shitty cars almost every day just to keep them going.

Hah, yeah. I like my shitty car projects. I'd like to replace my current daily driver, but I just can't get excited about new stuff, so it hasn't happened yet.

That is false, ignition coils go back to... before the sixties at least, when magnetos were used. And no bike that I know of ever had a distributor.

Every motorcycle has to have a distributor, unless it's either so new that it has coil-on-plug like modern cars, or it's so old it uses magnetos, or it's a single-cylinder engine.

That's not true. As far back as the sixties at least, both Harleys, Triumphs and Japanese motorcycles had either one coil for each cylinder or one coil (with two plug wires) for every two cylinders. They weren't mounted on the plugs, but up under the gas tank or under the seat. The plug wires go directly from a coil to a spark plug, so there is no distributor.

The purpose of a distributor on a car was to distribute the output of one coil to several spark plugs. When you have a separate coil output for each plug, there's no need to distribute anything.

I had a diesel car that I once drove with no alternator and no battery: started off a jump and drove to the auto parts store. Radio, windows, and lights were dead, but the car drove fine.

Fond memories of my Merceded W124. You could rip the engine out of the car and it would go on and on. No electricity for motor management required whatsoever.

I think you meant "rip the battery out"?

What I meant was the pure engine without any additional managment once running was able to sustain itself.

It's one of the last types of Mercedes which were meant to go through WWIII and back.

Either one works, as long as you're going downhill.

That's how diesel works, off its own compression.

Yeah - I remember when I was a volunteer firefighter - if you parked a fire truck in an atmosphere that was filled with combustible gasses, the engine would not shut off.

The trucks were equipped with some type of an emergency throw should that situation ever arise. We never had to use it in my time there.

Discharging a CO2 bottle into the air intake is the usual ticket.

Diesels don't require spark, but modern diesels use electronics for fuel injection, fuel pump, drive-by-wire throttle, engine monitoring, and so on.

Since at least the ~2000 era, a VW diesel will run with no alternator (for a while) but not without a battery.

I still own a MB with OM616 [1] engine. It does not need an alternator when it runs. Even to turn fuel supply on/off it uses mechanical valve which is on the dashboard. It turns 40 this year but it starts in a split second even in cold winter.

[1] https://en.wikipedia.org/wiki/Mercedes-Benz_OM616_engine

Diesel ignights via compression and does not require external ignition. For this reason, they can 'run away' and rev until they explode if somehow given too much fuel as the result of a failed injector or oil leak from the turbo that feeds the combustion cycle. The yt videos are intense.

> I realized at one point that it was probably EMP-proof

Different kind of bike, but I used to feel that way about my bicycles. However, sometime last year I was parking at the office and realised even that world is on its way out.

The No-True-Scotsman actual cyclists have largely moved to electronic shifting and such, and the utility bikes are quickly moving to e-bikes.

>The No-True-Scotsman actual cyclists have largely moved to electronic shifting and such

Not true at all.

Electronic shifting is a thing, yes: google for "Shimano Di2". However, road bikes with this are usually at least $4k: it's really something reserved for very high-end road bikes. I got a $3k road bike last year and it doesn't have it, nor does anything else in the low-to-mid range. It'll likely be a while before it comes to low-end road bikes (which are generally still "high end" compared to cheap Walmart bikes)

>and the utility bikes are quickly moving to e-bikes.

Again, not really. There's at least an order of magnitude difference in pricing between a regular utility bike and an e-bike. I've been to cities recently where many, many people commute by bike, and only a very small percentage are e-bikes, though they are getting more popular, but still they're a LOT more money than a regular cheap bike.

Roadies are merely one tribe of scots. The Realest, Truest Scots are the grant peterson/jan heine/PBP types, who have (by and large) yet to accept that downtube shifters are replacable with barcons. >:)

I love those motorcycles. Sometime back I wanted to build my own from parts. Started some research only to find out that some states (in the US) make it very difficult to register a custom built m/c. The assembly seemed easier in comparison.

If you plate the frame in vermont by mail, you're gtg.

Was the engine two-stroke?

Two cylinder, four stroke. Old Honda UJM with a small engine and fairly low compression ratio, so you could kick it over in one kick without breaking your ankle.

Heck, you could 'kickstart' some of them by hand.