The first thing you learn on the road to becoming a "good mechanic" is to be Observant. Look for the obvious. Look for the out-of-place. Look for the unusual.

Now before reading your post I didn't know a thing about cracked BMW coils. But I do know enough to know that a crack in a coil casing isn't a good thing. There is so much energy running around inside a coil that even a hint of moisture might cause the unit to fail. Moisture from riding in the rain, or from a bike wash, or even excess moisture from humid air.

> So (even with zero knowledge of BMW coil issues) if this bike came to my shop, the first thing I'd replace is the cracked coil. It may not be your problem now, but it will eventually become a big problem, so it gets replaced right at the start. There's simply zero advantage in waiting; it's ALL risk and zero reward.

> Being thorough in my work, the second thing I'd replace would be the plug wires AND the spark plug 5K Ohm caps. These things degrade with age, so at a cost of ~$10 it's the cheapest insurance you can ever buy. In other words, it would be stupid to put the old parts back on the new coil.

> Lastly, I'm going on something you INFERRED. You said you were checking the spark. People who are riding their bike don't "check their spark". Instead they simply go for a ride !! So I assume you must not be riding the bike, and the bike in all likelihood is simply sitting. Might be out of the weather and well cared for, but it's still sitting.

If that is true, then ethanol fuel is also sitting in the tank and in the carbs. And that is VERY bad. And here's how it affects you. It's my experience that old ethanol fuel will foul even brand new spark plugs in less than 5 seconds. So that if you tried to crank the bike with old fuel, then all your plugs are fouled. Meaning they will not even spark while sitting on the cylinder head. They are Dead. Deceased. Passed on. Gone from this life. Expired. (And every other term used in the infamous Monty Python parrot sketch.)

If your fuel is over 6 weeks old, then empty it all (tank AND carbs) into your car (which can't tell the difference) and buy all fresh fuel. Then toss all the older plugs into the trash bin, and go to the store and buy 2 new plugs.

That's where we start.

Hope this helps.

PS. Thank you for all the background info. You gave the model, the year, some history, and explained some of the steps you've taken, all without being prompted. That makes answering your question sooo much easier.

Thank you for your quick reply. Yes, my bike has been sitting for around 13 years, and my father told me if I could get to run I could have it. I've cleaned the tank out thoroughly with vinegar several times, then used a mild acid to etch the interior. I also recently rebuilt the carburetors and, having done a few carb rebuilds on dirtbikes, they should work well enough to at least startup.

I did post in this forum a few months ago, trying to figure out why none of my electronics worked, and I finally found that one of the positive leads was broken. After solving this problem I did have spark, though now I do not, now that everything else *should* work. I have around 150 psi compression on both cylinders, my petcocks work and fuel is flowing, I have a new air filter installed, and I have a brand new AGM battery. All the lights around my bike work and spark seems to be my only problem right now.

I've seen many suggestions to replace the coil packs on these bikes with Dyna Coils, but I was skeptical as to which specifical model of coil pack I should use on my particular bike.

Alternatively, is there a preferred method of testing the coil packs? I do not wish to play around with several thousand volts without a procedure.

Yes, my bike has been sitting for around 13 years, and my father told me if I could get to run I could have it. I've cleaned the tank out thoroughly with vinegar several times, then used a mild acid to etch the interior. I also recently rebuilt the carburetors and, having done a few carb rebuilds on dirtbikes, they should work well enough to at least startup.

> Vinegar IS an acid. "Google it."
> Such a second cleaning is uncalled for because BMW tanks are coated. All you probably did is remove the coating and now it WILL rust.
> You probably missed the enrichener jet in the bottom of the float bowl, which your dirtbike Mics don't have. A BMW won't start without those jets (1 LH, 1 RH) being clear and able to flow at least SOME fuel.

I did post in this forum a few months ago, trying to figure out why none of my electronics worked, and I finally found that one of the positive leads was broken. After solving this problem I did have spark, though now I do not, now that everything else *should* work. I have around 150 psi compression on both cylinders, my petcocks work and fuel is flowing, I have a new air filter installed, and I have a brand new AGM battery. All the lights around my bike work and spark seems to be my only problem right now.

> 1988 had another issue, you need to at least check for.... Disconnect one of the battery leads. Remove the front cover of the engine. Look for the light tan-or-white colored 3-pin connector coming out of the ignition "bean can". Defeat the clip and unplug the 3-pin connector. Hold the white connector body in your fingers and closely inspect it. The white connector is known to disintegrate over time. When it does, the ignition stops. If the white connector is cracked, flaking, broken, chalky, fractured, etc, then replace it. In other words, if it's not in absolutely perfect condition, then it must be replaced. Call Motorrad Eliktrik and talk to Rick Jones. He sells a replacement connector already attached to a 12" pigtail for about $28. All you do is cut the wire coming out of the Bean Can and splice in his 3 conductor wire. You'll be finished in 10 minutes.

A Photo of my 1988 White Ignition Connector

I've seen many suggestions to replace the coil packs on these bikes with Dyna Coils, but I was skeptical as to which specific model of coil pack I should use on my particular bike.

> And you should be. The internal resistance of the coil is KEY to the proper operation of the ignition. A resistance much different than the stock coil can burn up the ignition circuit board. I'm no expert, but smoking the circuit board is generally considered a "bad" thing.

Alternatively, is there a preferred method of testing the coil packs? I do not wish to play around with several thousand volts without a procedure.

Yes. The preferred method is this:

Remove old coils. Toss into trash. Install new coils.

Nothing has changed since I previously wrote you. A cracked coil case is 100% risk, with NO POSSIBLE benefit. If it is not the problem today, then it will be as soon as you're 300 miles from home. At that point the cost of a coil will pale in comparison to the towing fee.

Or, I guess you could call your dad to come get you. But because he reads this too, he's only going to say you should have replaced the coil, and then advise you to check into a motel because he's not going to be there until 11 the next morning. What's the price of a motel, breakfast, bed bugs, fleas, and a lost day of work ??

Or, I guess you could call your girlfriend to come get you. By the time she gets a tow vehicle and a trailer attached, then pays a mechanic to get the trailer lights working, then drives 600 miles, and finally gets home at 2:30 AM. The "thrill" will be all gone when she figures out she needs to get up in 4 hrs to go to work. That's going to cost you $75 in chocolates, $150 in flowers, and $4000 for an engagement ring just to be able to talk to her again.

New coils are cheap any way you want to slice it.

Hope this helps.

Yes, I know vinegar is an acid. The tank was full while the bike was sitting, so the coating was basically non-existent after a decade. Yes, I've done my research as far as the tank is concerned, as I plan to etch it again after I get the bike running in preparation of re-lining the tank.

I rebuilt the carbs following the instructions in the Bing book and a Clymer manual. I did check the passages you mentioned.

My issue currently is spark. I'm on a college budget and my goal at this point is to just get the engine to turn over and run at least a bit, so I can determine whether an entire rebuild is necessary. I cannot simply throw money at my bike at this point in order to fix it. If I need to purchase a new part I will, but I would like to know for sure that the part needs replacing before scrapping it.

I'm interested if anyone has any information on which Dyna Coil Pack I should use. The stock coil pack replacement was ~$260 from various places, while the Dyna Coil Packs were ~$100 and seem to be preferred over the stock ones. I just need to know which ones to buy.

I plan to replace the spark plug caps, spark plugs, and wires as well.

I'll take a look at that white wire underneath the front cover tonight.

You've picked a great bike to have for a "college budget" if it's running. I rode a R60/6 through 7 years of college myself. But this is not a great bike to choose to get running on a college budget. The bike is 31 years old and that makes it a "vintage vehicle". BMW parts degrade over time whether the bike is sitting OR running. And, BMW parts can be very expensive. So you got 13 or 14 years worth of catch up maintenance to do and it will get expensive. So as a reality check, you need to take off the "Dad's old bike" glasses, and look at the bike with "vintage vehicle" glasses to fully appreciate your predicament.

I'm not playing games with you here or pulling your leg. I'm trying to help you, but there are going to be some HUGE start-up costs associated with your dream of getting this bike running and ride-able. Let's just be honest and admit it may take well over a year to get it back on the road. But if you'll listen, I do believe you can crank the bike this month.

Yes, I know vinegar is an acid. The tank was full while the bike was sitting, so the coating was basically non-existent after a decade. Yes, I've done my research as far as the tank is concerned, as I plan to etch it again after I get the bike running in preparation of re-lining the tank.

Why re-coat ? 99% of the bikes in the world have no internal tank coating, including the dirtbikes you have experienced. So if funding is as tight as you say, why bother and why spend the money ??

I rebuilt the carbs following the instructions in the Bing book and a Clymer manual. I did check the passages you mentioned.

That's good. Spend the money after the bike is running on the later model ethanol-proof carb parts. You'll be much better served.

My issue currently is spark. I'm on a college budget and my goal at this point is to just get the engine to turn over and run at least a bit, so I can determine whether an entire rebuild is necessary.

Your experience with dirtbikes continues to cloud your judgement. Airheads will run 250,000 miles between engine rebuilds, storage or no storage. I can assure you the engine does not need rebuilding.

I cannot simply throw money at my bike at this point in order to fix it. If I need to purchase a new part I will, but I would like to know for sure that the part needs replacing before scrapping it.

If the coil is cracked and open to water it is dead, or will be shortly. I'm a degreed engineer who's been working a "side hustle" in the motorcycle trade since 1967. When I say replace the part, I really do mean replace the part.

I'm interested if anyone has any information on which Dyna Coil Pack I should use. The stock coil pack replacement was ~$260 from various places, while the Dyna Coil Packs were ~$100 and seem to be preferred over the stock ones. I just need to know which ones to buy.

Well smart guys have at least 2 options: a) You can measure the resistance of the primary winding and then match that with one from the Dyna web site. Or, b) you could figure out a way to get me your text number and I'll send you a replacement BMW coil off another 1988 model.

I plan to replace the spark plug caps, spark plugs, and wires as well.

Good. Smart. Now we're talking.

I'll take a look at that white wire underneath the front cover tonight.

Look again at the photo I sent you. White connector.

Hope this helps.

I've been busy with labs and exams for the past week so I didn't get a chance to look at the white connector that was previously mentioned. Then when I went to view the photo of it, the link had expired.

I went ahead and looked at the only white thing in the front of the engine that I could find:
https://photos.app.goo.gl/Dnp2k2ZaqkYk7qFU9

But that didn't look like a connector, so after a second inspection I noticed a connector caked in grease and stained yellow, but maybe it used to be white. I sprayed it heavily with DeoxIT and brushed all the crap off of it:
https://photos.app.goo.gl/bjBGyt64Qhmaaruv5

Whichever it is, does it look like its in decent enough shape?

On another note, I did some more research as to which coils are correct for my bike, and I've decided on this pack:
https://www.euromotoelectrics.com/Dynatek-0-7-Ohm-Dual-Tower-ignition-coil-p/dyna-coildc9-1.htm

Oh man, I hated those autumn and winter labs. Prof would blather on and on about something not related to Materials, Metrology or whatever the lab was supposed to be. I'm standing there looking at my watch, seeing it's already 9:30PM and getting colder every minute... and thinking... it's going to be a bitter cold R60 ride back to my home 45 miles away. Treasure those days !

Your first photo is the alternator. You can tell it's an alternator because its got a slip ring. It has 3 wires because its a 3-phase alternator. Those wires are rather heavy because of the high current coming out of the alternator.

Your second photo is the beast you're looking for.... 3 much smaller, low-voltage, low-current wires on a lead coming from the smaller diameter "bean can", which is below the alternator. (The ignition devices are rotated by the crankshaft, and so you'll see the bean can aligned directly with the end of the crankshaft.) The black connector never gives any trouble. Defeat the latch that holds the 2 connectors together and unplug the pair. Inspect the white housing for cracks, flaking, dusting, chalking... any type of materials degradation. If everything looks good, you'll still want to clean the 3 contacts on both sides before plugging it back together. You might even use a dab of No-Ox-Id on the 3 contacts to keep the weather OUT and keep the electrons flowing. The electrical pulse which triggers the coil and travels through that connector is about 2V. So ANY minuscule corrosion or misalignment of the contacts kills the ignition system completely. And that's why you need to closely inspect that specific 3-pin connector.

BTW... Be very careful when re-fitting the cover. It looks easy, but it is possible to pinch one or both of those wires between the engine block and the cover. When you tighten the cover bolts it will cut through the insulation and make lots of big trouble. Don't ask me how I know this.

Hope this helps.

Primary winding resistance from a BMW gray coil using a reliable digital Ohm meter was 1.8Ω

I replaced the coil pack, nothing.

The white connector in the front of the engine turned to dust in my hands when I disconnected it.

• 1988 had another issue, you need to at least check for.... Disconnect one of the battery leads. Remove the front cover of the engine. Look for the light tan-or-white colored 3-pin connector coming out of the ignition "bean can". Defeat the clip and unplug the 3-pin connector. Hold the white connector body in your fingers and closely inspect it. The white connector is known to disintegrate over time. When it does, the ignition stops. If the white connector is cracked, flaking, broken, chalky, fractured, etc, then replace it. In other words, if it's not in absolutely perfect condition, then it must be replaced. Call Motorrad Eliktrik and talk to Rick Jones. He sells a replacement connector already attached to a 12" pigtail for about $28. All you do is cut the wire coming out of the Bean Can and splice in his 3 conductor wire. You'll be finished in 10 minutes.

You have to call, this part is not shown on his web page. Bought mine about a year ago. Rick is a really nice and knowledgeable BMW guy. You'll like doing business with him.

You have heat shrink and solder, right ??

Yep, I have electrical stuff.

I'm assuming they aren't open at 6 on a Sunday so I'll call them tomorrow.

I assume this type business is run out of his home. Call and see. It certainly can't hurt.