Welcome aboard ! Interesting story.

Maybe you could give us more detail on the ignition system. Is it running stock points, stock EI, or an aftermarket EI ???? I'm not clear on that point, AND inside the front cover is your starting point. So small details like that make a big difference in the approach.

The engine cranks but won't turn over.

Maybe you got this wrong ? Or am I misunderstanding ? So I can fully understand, didn't you mean the battery/ electric starter will rotate the engine, but it still doesn't start ??

However, I don't get the "clicking" that would indicate a dead battery. I checked the drop in voltage upon ignition, and it remained above 10V.

Clicking from the starter or starter relay ?? What clicking are you talking about ?

Wouldn't the condition of the lights be a better, more measurable indicator (or metric) of battery condition ? Since no one here heard your "clicking" before the issue showed up, how are we supposed to compare it to the new "non-clicking" sound to obtain a useful indicator ?

Also, if I am not getting spark, then a fully charged battery won't do me any good.

Well, since the entire ignition system function is based upon having an operational battery, I completely fail to follow the logic of this statement. Care to re-state ?

Would my next step be to check the resistance on the coils...primary/secondary? I guess I am wondering if there is somewhere else I should look besides the coil. Any insight would be appreciated. Thanks!

Coils will run 25+ years and hundreds or thousands of miles before failing... if ever. Stock coils did fail, but you don't have stock coils. So how did coils get to be the primary focus ? You are having trouble simply because you are NOT proceeding in a logical fashion.

• No sir, I suggest we start as always with the simple stuff that's 100x more likely to fail, like battery condition, battery connections, and fuses.
• Then we remove the front cover, and if points ignition, we make sure the points are opening and closing properly. If EI, then we check the connectors.

And as far as battery condition, do this....
• Disconnect one or both of the cables from the battery terminals
• Pop the tops of the battery and make sure ALL the cells have a visible fluid level
• Place the trickle charger on the battery for 4-6 hours
• Connect a spare 12V headlamp or tail lamp bulb (NOT ONE connected to the bike's electrical system) across the battery terminals for 2-3 minutes
• ASAP, connect a DC voltmeter across the 2 battery terminals and tell me what the battery reads

Your battery reading needs to be well above 12V to be viable. Hopefully between 12.3 and 12.8V when reading right off the battery terminals after charging.

Right now, here's what I believe happened... Using the chargers somehow blew a fuse, or a reverse connection killed one cell inside the battery. But the bike did crank and then ran on the alternator and damaged battery. As long as the engine was running the alternator supplied all the power needed. However, when you got back to the garage and the engine returned to idle, there was not enough battery to take over from the (now) slow turning alternator. So the engine coughed and died. The ignition system MUST have adequate electrical power from either source, which seems to be missing now due to an impaired or deceased battery.

Only a clearer description and battery testing will tell us.

Hope this helps.

Thanks for your input. Indeed, it does help.

Here is an update on the ignition system:

Aftermarket Enduralast Heavy Duty Ignition. Stock ignition trigger. Also has 450W alternator upgrade from EME.

Admittedly, this is the first airhead I have owned with EI. I clearly have more reading to do, and will do so.

I came home today and saw that the trickle charger indicated that it was fully charged. I tried to fire it up, but no luck. (yes...the battery/ electric starter will rotate the engine, but it still doesn't start. And I was referring to the starter when I referenced the clicking that I would have expected in the previous post).

This time, a screeching sound (that's the best description I can think of) came from what seemed to be the front of the bike . This sound wasn't present the day before...but the battery was likely not at full charge at that point. The battery is currently sitting at 12.9V.

I was reading over what the PO had sent me when I purchased the bike from him. I hadn't noticed before that it was a 9 year old battery (Panasonic AGM). I had glanced at the battery before I charged it, and thought it was a flooded battery. It definitely is not and I was definitely too hard on it.

I've got some more digging to do. Will proceed with recommended battery test.

Still no basic information to report on the lights ?

The OEM ignition trigger has an Achilles's Heel in the white/ivory connector coming out of the "bean can". These connectors disintegrate, and when that happens the engine will not fire or run. I suggest you remove the cover to investigate the noise, and have a quick look at the 3-pin connector.

The Panasonic battery gets VERY high marks, but 9 years on a battery is almost unheard of. 12.9V is very high and must be the reading directly after charging, but without the suggested bulb draw-down procedure.

Hooked up a tail light to the battery for 2 minutes, and it did not dim. Checked voltage afterwards: 12.77V

Looked at the ignition trigger connection. Definitely degraded, but not as badly as in the picture you posted. The missing pieces of the male end still reside in the female end of the connector.

If I am thinking about this correctly...the battery actually seems fine. Would the state of the ignition trigger cable in the attached photo be enough to cause a disruption?

Hooked up a tail light to the battery for 2 minutes, and it did not dim. Checked voltage afterwards: 12.77V.

Dimming was NOT the object; finding the TRUE voltage of the battery was. Your true battery voltage is 12.77V. That's very good.

Now I only need to hear about the lights. This is the third request.

Looked at the ignition trigger connection. Definitely degraded, but not as badly as in the picture you posted. The missing pieces of the male end still reside in the female end of the connector.

Brother, this is the difference between your observations and mine. That connector definitely needs replacing. Call Motorrad Eliktrik and order the pigtail they offer. It's about $29.

If I am thinking about this correctly...the battery actually seems fine. Would the state of the ignition trigger cable in the attached photo be enough to cause a disruption?

You've got a 40 year old vintage vehicle with an undocumented service history, and you want me to tell you that's the only issue ? I don't think it works that way. I believe in fixing all the issues found (like the ignition connector) while going through the proper service steps one by one... in the comfort of your shop.

In this way you not only get the bike running again, but discover and repair issues that might become BIG problems out on the highway. A prudent person takes these steps while they are servicing their bike. Performing the 'bare minimum' is a great way to insure a long hike home.

All the best.

Wobbly: Was looking over your previous posts to determine what the third request was regarding the lights test. What the lights do when I attempt to start the bike? Sorry, but could you restate?

Fair enough regarding the ignition trigger connector. Ordered.

8166: Will proceed with ignition trigger testing. Thanks for the resource.

Kill switch not engaged.

Here are a couple of photos. Let me know if another angle would be helpful.

Thank you both for the responses. I appreciate your time.

Regards

Wobbly: Was looking over your previous posts to determine what the third request was regarding the lights test. What the lights do when I attempt to start the bike? Sorry, but could you restate?

Simply tell me what the lights are doing when you turn the ignition key to the "ON" position. I know some models will turn them OFF during the cranking process, but that's not what I'm after. I need to use the operation of all lights to indicate 1) the fuses are good, 2) fairly normal harness function, and 3) fairly good battery function.

Remember this exchange ? ...

Would my next step be to check the resistance on the coils...primary/secondary?

• No sir, I suggest we start as always with the simple stuff that's 100x more likely to fail, like battery condition, battery connections, and fuses.

99% of BMW repair is simply checking the "simple stuff". So let's finish checking the simple stuff.

Wobbly: All lights accounted for (head, tail, turn). Nothing out of the ordinary on that end.

8166: Read through the ignition trigger test you suggested, but unfortunately haven't had time to run through it. I will try to get to that tomorrow. And yes, the damaged lead is question is what I ordered. There definitely wasn't any corrosion on connector spades, but I reckon that is a moot point considering the connectors condition.

Also, the cover that was missing in the photo was previously on. I had only taken it off while I was rooting around. So something getting in there is one thing that can be ruled out.

Will update as soon as I test the trigger.

Thanks

Yes, it has been a while...but I finally did get around to testing the ignition canister.

Got spark on the grounded cylinders. So, at least I know what I am in the market for now.

I've found a replacement hall sensor, but I was wondering if you had any recommendations?

I've found a replacement hall sensor, but I was wondering if you had any recommendations ?

Yes, replace the plug wires with Metal Core wires. And replace the spark plug caps with 5K Ohm NGK.

Or you can get a set of pre-made plug wires from Motorrad Eliktrik.

http://motoelekt.com/ignition.htm