Barebones wiring suggestions for a 96 Sportster, David Bird chopper conversion

[farmall]

The point of running an electronic ignition is to get rid of the advance mechanism and associated wear. If it shits on the road, ya walk (or have a complete points setup in your road bag which is a fine idea no matter what ignition you run because unless a coil dies you will get home).

The point of running a mechanical advance (but with points) is easy roadside repair, ability to run at lower voltages than EI tolerates when limping home with electrical troubles, very fast troubleshooting, cheap replacement parts and they work very well with kickers.

I'll run either but my kick only-bikes get points. The EI bikes don't get mechanical advances because that's what electronic ignitions are for and there is zero functional advantage to a mechanical advance with an electronic trigger over an electronic trigger with (often adjustable) electronic advance.

Inline fuses should of course be modern blade fuses. Glass fuses are delicate corrosion-prone shit. I prefer circuit breakers and won't run fuses on new installs, but you can have the best of both worlds with the blade style inline circuit breakers which drop in to fuse holders. I suggest buying online for best selection.

This wikipedia piece explains the ATO fuse system and shows sizes. You can save a lot of bulk by running small fuses. ATO circuit breakers are made to the same connector standard. https://en.wikipedia.org/wiki/Fuse_(automotive)

Silicone dielectric grease is ideal for protecting blade fuse connections, plug/socket connections (like Harley alternator connections which are otherwise prone to oil intrusion and degradation), terminal studs and more.

Check other Chop Cult wiring threads for posts on how to buy supplies, crimpers etc. Forget the usual auto store junk. A wiring kit isn't expensive and makes life easier so assemble your own.

[Skjoll]

... The EI bikes don't get mechanical advances because that's what electronic ignitions are for and there is zero functional advantage to a mechanical advance with an electronic trigger over an electronic trigger with (often adjustable) electronic advance...

IMO the simplicity of not having both a trigger and an ECM is why an HEI has an advantage, it connects straight to the coils just like points yet without the wear issues that points have and it's just as easy to pack a spare HEI and install it if necessary like a set of points. FWIW, I have never had an HEI go bad despite running them on my race bikes and air cooled VWs for hundreds of thousands of miles. As for the advance I can see if a mechanical one is or isn't working and can fix it or find a temporary workaround out on the side of the road... try doing that with a VOES and ECM setup. So in my eyes an HEI has the best of both worlds although I'm assuming you see it as a compromise on both accounts.

I guess the whole thing boils down to what the user feels is most important... the same reason why there's a constant debate over passive vs active pickups on guitars.

[JBinNC]

IMO the simplicity of not having both a trigger and an ECM is why an HEI has an advantage, it connects straight to the coils just like points yet without the wear issues that points have and it's just as easy to pack a spare HEI and install it if necessary like a set of points. FWIW, I have never had an HEI go bad despite running them on my race bikes and air cooled VWs for hundreds of thousands of miles. As for the advance I can see if a mechanical one is or isn't working and can fix it or find a temporary workaround out on the side of the road... try doing that with a VOES and ECM setup. So in my eyes an HEI has the best of both worlds although I'm assuming you see it as a compromise on both accounts.

I guess the whole thing boils down to what the user feels is most important... the same reason why there's a constant debate over passive vs active pickups on guitars.

This is why I mentioned the Dyna S.

Jim

[Skjoll]

This is why I mentioned the Dyna S.

You're right, I'd forgotten just how popular the Dyna S was decades ago when a lot of riders got sick of dealing with points.

[farmall]

HEI is specifically a GM automotive ignition design though the module pinouts of the era permit Ford and Chrysler interchange (outside the distributor of course). It doesn't fit motorcycles, early Boss Hoss V8s of course excepted.

If you mean Pertronix style ignitions (Compu-Fire is a Pertronix brand who offer both mechanical and electronic advance models) they are electronically quite reliable and were first used to replace points on pre-electronic ignition systems and famous air cooled VW upgrades. They retain the stock advance for simplicity including the ability to fit more engines with fewer stock numbers since timing is performed by the stock mechanisms. Pertronix are successful because they cover more car, truck and tractor engines than any other make.

VOES malfunctions don't render a Harley unrideable unless the diaphragm leaks leaning the mixture. If in doubt, ground the VOES lead from the ignition module then pull and plug the vacuum hose. Fast and easy. (I'm lazy so I like everything fast and easy.) The VOES vacuum switch exists to retard the engine under load.

Roadside fixes for anything require spare parts i.e. basically a spare ignition so any ignition can be a spare because any ignition can be installed at roadside.

I've replaced far more mechanical advances on customer bikes than VOES. Advance units do come apart (usually after neglect) and get sloppy with wear. The old trick of using a washer under the advance retaining bolt to lock the points cam was rightly popular.

[JBinNC]

I have replaced far more mechanical advance units than VOES switches as well, because they have been in use longer (since 1970 for the cone cover version). But the VOES switches are catching up fast, because they have been around long enough to start falling regularly from age.

I think the discussion is about simplifying the wiring, and a simple ignition is part of the recipe. That doesn't make it the best ignition, however. I suppose if we want real simplicity, we could go back to hot tube ignition and atmospheric intake valves.

Jim

[Skjoll]

HEI is specifically a GM automotive ignition design though the module pinouts of the era permit Ford and Chrysler interchange (outside the distributor of course)...

Since I kept mentioning 'Hall Effect ignitions' (here and in the 'Points in early Evo BT?' thread)I assumed that HEI was an appropriate acronym to use and wouldn't be confused with the Delco-Remy HEI (High Energy Ignition).

[Coleboi]

Your cam position (actually ignition pickup) must be connected, like it was stock, to the ignition module to provide the timing pulses or triggers. Otherwise you get no spark. It would pay you as well to keep the stock VOES switch and wiring if you are using the stock ignition module (or other electronic module for that matter).

Jim

Jim, can you bypass the electronic ignition? I’m running a 4 position momentary key turn with a fuse box. Run coil to ignition module back to the fuse box to key for spark?

[JBinNC]

Jim, can you bypass the electronic ignition? I’m running a 4 position momentary key turn with a fuse box. Run coil to ignition module back to the fuse box to key for spark?

No, you cannot "bypass " the electronic ignition. You have to have some kind of ignition. There are simpler systems (as touched upon in this thread). You will always have a coil, a pickup, a module, and usually a VOES switch or MAP switch. On most aftermarket systems, the pickup and module are combined in a unit that fits in the cam cover on the motor. That will make the wiring simpler than the factory systems with separate modules.

Jim