BMW motorcycle ignition

SOURCES for/of INFORMATION AND REPAIRS THROUGHOUT THIS ENTIRE ARTICLE SHOULD NOT BE TAKEN TO MEAN THAT THEY HAVE MY UNCONDITIONAL APPROVAL. They are listed for your information ONLY! I have tried to make some pertinent commentary on them when this applies.

For further information, see Haynes, Clymer's, or other manuals; just be cautious for errors in those manuals. They are, frankly, not all that good on Ignition items and testing, and certainly not for the innards repairs.

Remove one spark plug. SECURELY fasten the threaded metal body to a cylinder or head fin. You can use a bungee cord for this. Leave the spark plug cap connected to the spark plug.
Next, disconnect all battery negative terminal wires. Remove front cover. Reconnect battery. Remove the bale wire from the three prong white connector (the one leading from the canister ignition).
You can now disconnect the connector halves. Disconnect, and reconnect. See if the engine now has sparks....if so, you had some corrosion on the connector spades. Assuming no spark, disconnect the two halves again. Use a bent paper clip or whatever and insert it into the center connection on the engine side connector. Turn on the ignition, be sure kill switch is centered to run position. Repeatedly touch the paper clip to the engine case, which grounds the center connection. You should see sparks at the spark plug (darkened room may help). If none, you have problems in the module or power to it, or an open coil primary. If you DO get sparks, you have a bad canister.

The three pin connector that connects the three-wire plug from the canister to the bike wiring has a thin wire bale clip around it. That bale clip MUST be removed before you try to unplug the connectors from each other. Pry an end of the bale wire clip, or both ends, with a tiny tool, and then carefully remove that bale wire clip. THEN unplug the connectors. Don't lose the bale wire clip; reinstall it after you push the connectors back together. The 3 spade connectors in these male and female plugs are known to get very minor corrosion, sometimes invisible, and cleaning with an eraser and then a slight poof of contact cleaner-treatment, will likely fix the problem. Corrosion can exhibit itself particularly on the electronics ignition models from 1981, with intermittent ignition problems.

Canister with Ignition points:
Ignition points as used in canisters, that is, 1979 and 1980 models; unconfirmed data: Bosch GB534...as on Mitsubishi Colt (69-80 6 cyl), some VW (Bus to 1972 for instance); Volvo, some Toyota, Ford Cortina TD and TF, 6 cyl Falcom XY and XD, ....etc. Old VW points springs may be too weak, and cause floating problems. NOTE: Porsche, and some others, used Bosch GB752, which had a slightly higher spring tension, so less tendency to have floating problems at VERY high rpm.
The 1979 and 1980 motorcycle canisters with points did NOT have a felt pad to help keep the points cam lubricated. If the lubrication on the points cam dries out, the rubbing block and the cam can make loud chirping noises. This indicates that the rubbing block is wearing fast, and soon the points will have no opening, and the bike will quit running. Remove the outer lid (2 screws) and lubricate the cam and sides of rubbing block....all sparingly....with a high temperature grease. Put one drop of a decent oil on the outrigger bearing. NOTE that the points can NOT be adjusted properly withOUT the outrigger bearing in place.

NON-canister points: Ignition points for 1970-1979 Airheads: BMW has been shipping wrongly made points sets, made in China. The rubbing block is too long, and you cannot get proper timing, etc. I suggest the Noris points from such as Beemershop, etc. Rotating the points plate Clockwise will retard the spark.
****NOTE!! The NON-canister Airheads have points located on the end of the camshaft in a small engine cavity. The lower points screw heat is very close to the points spring, and if a wrong screw or washer is use, the screw can contact the spring and the points are effectively shorted, and you get no ignition. This is seen now and then right after someone replaces the points and can't understand why the engine will not start.
****NOTE!! The ignition points wire that leads from the points cavity to the rest of the motorcycle fits through a rubber protection grommet, and this grommet often gets displaced when working in the area. DO NOT replace the cover until the wire and grommet are in proper place, or you can cut the wire when replacing the cover.

Before the 1979 introduction of the canister, the Airhead motorcycles all had points ignitions with felts, and the felt AND cam required lubrication (both on the engine cam's shaft inside the ATU, and the ignition cam outer surface). Since the automatic advance unit was at the cam tip (not buried as in the canisters), the automatic advance unit cleaning and lubrication could be done rather easily; with two types of Bosch greases used, one for the rubbing block, one for the area between automatic advance and cam....and the shaft. The canister is not so simple to service, to say the least. I personally lubricate the cam in the 1979-1980 canisters that have points, and I do it very very lightly. There is no felt in most if not all point sets for these canisters.

High idling rpm, perhaps it came on slowly worsening, is often the cause of one of two problems. Occasionally from both.
One of these problems is a sticky automatic timing unit in the ignition canister at the front of the engine.
The other problem is leaking intake manifolds or mis-adjusted carburetors (usually the idle mixture screw) or, no slack in one or both throttle cables.

Perhaps THE most common problem, is a sticky automatic advance unit, that results in a high idle speed, typically after a full warm-up of the entire engine. A full warmup takes at least 10 miles, often 20. You must have the ENGINE CASE fully hot, NOT JUST THE CYLINDERS. The PROPER fix is to disassemble the canister and very carefully clean and re-lubricate it. This project is not easy for the novice. Sometimes removing the oval side plate and squirting in a cleaner and then a fine oil (NOT EVER WD40!) will help, but may or may not hold up over time. When disassembling the canister, some of the ATU parts may need to be burnished (sort of a more complete polishing) which DOES help, when necessary. Typically a careful cleaning and light lubrication is enough; but a judgment call is needed about burnishing, which removes a minute amount of metal, to enable smoother operation. I try to do what is necessary, so when the ATU is HOT, it does not bind in the slightest.

There are several TESTS for proving that the ATU is at fault for a high idle rpm after warmup (rare, before warmup) (and not, say, a vacuum leak at the intake rubber hoses, no free play in the throttle cables; or a mal-adjusted idle mixture screw).
In some instances, just turning off the engine and restarting it after it was already hot and exhibiting the very high idle, is enough to reset a stuck ATU from the inertia of beginning ATU rotation, so try that. If that then shows a normal idle, it is likely a ATU problem. A few repeats, and if this is the situation, you can be nearly 100% sure it IS the ATU needing attention. YOU CAN DO THIS YOURSELF.

If restarting doesn't show up the problem, then DO get a friend's help. First take the bike for a 10-20 miloe ride, and if the idle rpm went quite high after a FULL WARMUP of the ENGINE CASE, then pull the bike up to a nice big object, like a brick building. You could also just use the front brake.
With the bike in gear, let out the clutch very slowly, loading the engine, and thus slowing the engine to about 900 rpm. Have a friend use a timing light, triggered from the left spark plug, point the light at the timing hole. If the timing is well-advanced and not where it should be (~S mark), then the ATU IS THE PROBLEM. Prove it by pulling in the clutch...you have a high idle rpm again, yes? Try several times to be sure.

If the increase from the ~900 rpm test is SLOW, and the timing is OK, then try tightening the intake rubber hoses at carburetor and at cylinder head, and then start the engine and let it idle, and spray brake cleaner at that hose and its ends...no rpm change should be noted. If OK, re-synch the carbs (don't even think about doing this unless you KNOW the valves are properly set, as tight valves will mask all your analysis and work). During the resynchronization, pay especial attention to the idle mixture screw, idle balance, and ending idle rpm (1000-1100). Go back and forth until all adjustments are OK. If you take more than a few minutes for all this, either ride the bike to cool the engine a bit; or use fans blowing on the cylinders. My website describes how to get an appropriate squirrel cage fan for nothing.

A problem seen now and then is a Hall device failure. Often, but not always, seen as a complete failure, they have also been known to become intermittent; often with temperature changes. USUALLY, but NOT always, the Hall problems occur after a very thorough engine warm-up; the ignition gets intermittent, or dies. In some instances, the ignition can fail for a few seconds only. The devices are replaceable, but BMW only sells the complete canister, VERY pricey indeed....but with this article YOU can repair them, or send them to someone who will! ALWAYS check the module to be sure (unless riveted type on the later headsink) it has good heat sink paste under it. Failure to have good condition heat sink paste under the module will cause it to overheat not too long after the bike is started, and the ignition typically acts up or totally quits, until the module cools down. After enough of these overheating occurrences, the module WILL FAIL.

****A RARE, but super-annoying problem, because you likely will go CRAZY before you find the answer, is one of the 1981 and later electronic ignition airheads, that typically will idle OK, but won't raise its rpm up properly. This problem acts somewhat similarly to a hole in the carburetor diaphragms. The actual problem is a poor ignition kill switch at the bars. Cleaning that switch may not fix the problem. Bypassing the switch will show whether or not the problem is that switch or not.

Troubleshooting Ignition Trigger, as posted to the BMW Airhead Boxer mailing LIST, on 19 April, 2001, by John W. Snider.

Ignition Trigger Repair Bulletin, by David A. Braun. http://www.deathstar.org/~flash/ig_trig.html
disclaimer: I was accused of plagiarism by him. After some correspondence, he agrees that I had not, and my information predated his.
I am listing the URL here, because it is useful, and I do NOT hold a grudge, nor any ill-feelings. I only mention this incident because it
...or some anyway...got published, and published things tend to last forever, whether or not someone sees the follow-ups.

Hall devices: Honeywell (MicroSwitch) part #2AV54. This is available from Newark Electronics as part 96F1986 www.newark.com
Another source for the 2AV54 Hall Effect Device: http://www.onlinecomponents.com/
Reported other sources: Siemens HKZ101....available from www.Jaycar.com in Australia as ZD-1900. I suggest you compare prices from the various sources.

Note that the Honeywell device, in case you try to find it on the Honeywell website, can be difficult to find. That is usually because its official name
on that site is a "Hall Effect Vane Position Sensor". You can TRY using this:
http://www.honeywell.com/sensing/
You will still have to mess around to find the correct page....Honeywell constantly plays with location addresses in its website. You don't need to go find it, unless very nerdy, because I have
all the needed information, and then some, right here on this page.

UNconfirmed information is that the Hall units may be found in 1979-85 VW; 1978-1983 Audi; 1979-1982 Porsche; and that Bosch 1237011052 may be the number.

***I have thought about recommending that everyone get a replacement Hall device; before they stop making them. My decision, so far, is that this
is quite premature, because of the many sources, new and used.

Red, power; black, ground; green, signal

OLD units had the sensor plates screwed together and the rivets were hollow; later plates were a push fit, solid rivets.

NOTE FOR THE NERDY: This is a schematic of the Hall Effect device. Note that the output is an NPN transistor with open collector.

Ignition modules (the flat black box under the fuel tank)(mounted vertically or somewhat horizontally flat, depending on year and model of bike):
Common ignition problems (1981 and later, except riveted modules) include failure to clean and renew the heat sink paste under the Module under the fuel tank at reasonable intervals. If the heat sink paste is old and dried out, the Module will tend to overheat and cause ignition problems after the bike has been on the road awhile; and too many overheating cycles will result in module failure.

There is more than one place of location for the ignition module on the Airheads (1981+) depending on the MODEL OF AIRHEAD and the YEAR.   The 1981-1985 R80G/S, 1983-1984 RT80ST, 1981 to 1987 R65, 1982 to 1984 R65LS, 1985 to
1987 R80 and R80RT, and the other bikes from 1988, all have the ignition module on the right side of the frame backbone tube (under the fuel tank) and are just behind the COIL. All other earlier models have the ignition module located directly under the tank, on a piece of flat aluminum plate, which is attached where the old ATE master cylinder was located. Modules that are screwed/bolted to the attached plate can be unfastened by those fittings, in order to clean the bottom of the module, and the plate, before applying fresh heat-sink paste.

Listed here are reported modules that MAY work.   The word MAY is being used here, because there MAY be complications, particularly if you have the very latest 0.7 ohm single coil with twin towers. Read the COMMENTARY by Oak, that is just below! Also note that Oak has explained MORE about the confusion over the ignition modules and coils,
in an article in the November issue of AIRMAIL.   I have mostly the same information here, of course.

Bosch 0227-100-116; GP Sorensen; 11-5064; NAPA (Echlin) TP100 (supposedly from Globe Motorist, but will not sell small quantities, and Napa prices are vastly higher, but worth another look); Standard Motor LX501; Wells Mfg RB100. MANY cars use similar modules. They may not be same for logic and timing, but probably will work, don't leave the key on for long periods of time with engine not started.

         Modules for Airheads: Transpo BM-300 Rocky Point Cycle.com    Also has #9604, Ignition Module, made in the USA, for the R bikes and also has Part number 9608, Ignition Module, made in the USA, for the K bikes.
                   Also sells the Boyer-Bransden Ignition....a curve for the Microdigital is later in this long page.

         VAG (VW and Audi) ignition module part nr. 191 905 351b is a drop-in replacement for the earlier airhead modules.
         Cars that you may find modules on in wrecking yards, or can get modules at auto-parts stores:
         VW Golf and Passat 1979-1989
         VW T2 Transporter and Jetta 1979-1992
         VW Scirocco 1979-1995
         VW Corrado 1979-1995
         Audi 100 1980-1993
         Audi 80   1979-1993
         Audi Coupe 1981-1994

Due to changes made by BMW, and confusion over the issue, I decided to greatly expand this area. However, Oak beat me to it. Somewhat below I am printing his commentary, as published to the Airheads LIST on May 11, 2011, edited by me for clarity.   I have NOT included here the information he published in November 2011 AIRMAIL, since I have already covered it here.

Note that Oak had posted back on December 6, 2003, some of the same information. I used to have that information in this article, but have dropped most of it, as Oak's May 11th, 2011 and November 2011 information is better.

Here is one part that I wrote previously that I am leaving, and this part is in BLUE, slightly edited here.

The Ignition Modules (under the tank modules) were initially made in two versions. On these early modules, a spark could occur when the key was first turned on. One version was for the kickstart bikes, one version was for the no-kickstart bikes. The original modules had a timing feature that cut off the current flow AFTER about 5 seconds for the kickstarter equipped bikes, and about 1 second or so for the NO kickstarter equipped bikes. Later this was changed to about 1.5 seconds (UNclear to me, but perhaps this 1.5 was for both...or for the kickstarter equipped bikes...not sure). The kickstart modules timings were originally longer to allow time to kickstart the bike. Which is a bit strange, since engine rotation causes the modules to be triggered anyway. The reasoning behind the shorter cutoff for later models is to lower heating of the coils, which supposedly was THE, or only one of the, causes for the original twin-tower gray coil to fail by cracking. Apparently, some folks would turn on the key, and continue a conversation, without starting the motor. Perhaps some very early modules never had a timer at all. The coil redesign for reliability (no more cracking) did not result in any change in the electrical characteristics of the coil.

Another thing about the earliest modules was that the module could misfire between the two cylinders. Weird, but, yes, could happen. BMW eventually cured this problem in later modules. BMW also fixed the modules so that there was NO SPARK unless the engine was being rotated.

This module and coil information confusing is just that........confusing. Some simplifying hints are just below. NOTE that if the module has white or pink lettering, it is only to be used with ignition coil 12-13-1-243-910. This applied to all engines BEFORE 1991. If the number on the COIL is 12-13-1-244-426, then you NEED the latest upgraded MODULE. What is completely confusing to many, is that the early and later modules use the same part number. The last of the TWO modules has TURQUOISE lettering, and it is usable with ALL the coils, including the last high powered coil. That coil ends in part number -426.

***NOTE AGAIN that the PART NUMBER for the old modules replacements was NOT changed, and a paint code used to identify the changed modules.

OK...now here is the last part of the confusion.   The very latest module, usable with all the coils, has that turquoise lettering.   But, it came in two versions:
12-14-2-325-284
12-14-2-325-550
ONE of these fits YOUR bike....because the only difference is the MOUNTING.

Another problem, not so rare, is with the last models of the Airhead. This does NOT apply to earlier models, and NOT to two coil models. If your bike is hard starting, you may have a problem with the early version of the Ignition Control Module, located under the fuel tank.     Versions of these that HAD the problem are coded by paint markings, of PINK...and (OR) WHITE.   The updated module is 12-14-2-325-284.....with turquoise paint mark; some bikes had the other mounting, -550 module.
NOTE!....if your bike has had this hard-starting problem, or single cylinder running until it warms a bit and nothing has seemed to fix it, and you don't want to install that new pricey module, nor an aftermarket one, you can try a little trick. When your bike is not starting immediately, SHUT OFF the ignition kill switch, then turn it back on immediately, then try starting the bike.   This is not well known, and to my knowledge Oak never wrote about it (??).

There is an interesting way to find out the 'time' for cutout, not that it means much to you, actually.    Watch the fairing voltmeter....or any voltmeter attached to the system. You can also get fancy and watch the proper terminal at the module. From key-on, the bike's voltmeter with most old modules, drops a bit, and may continue to slowly drop....note the time from the initial small drop TO where the voltmeter gives a wee jump UP, ...it is quite noticeable. Some have used modules from various cars. OR, from Stan at Rocky Point Cycle. I fail to see how this is a big problem, again, don't leave the key on without starting the engine. A RARE, but super-annoying problem, because you likely will go CRAZY before you find the answer, is one of the 1981 and later electronic ignition airheads, that typically will idle OK, but won't raise its rpm up properly.    This problem acts somewhat similarly to a hole in the carburetor diaphragms.   The actual problem is a poor ignition kill switch at the bars.   Cleaning that switch may not fix the problem. Bypassing the switch will show whether or not the problem is that switch or not. But, that above problem can also be a wrong module, see above paragraph.

OK....here is Oak's May 11, 2011 commentary...EDITED BY ME FOR CLARITY:
"1) The ICU version with the heat sink riveted to the ICU is BMW's very latest. The part number is 12-14-2-325-284. It is now BMW's standard replacement part for ALL models from 1981 forward and has ALL the updates, and is applicable for both the kickstart and non-kickstart models. The ICU comes now with the aluminum heat sink attached and is NOT meant to be serviced by removing and cleaning and installing fresh heat sink paste, as were prior NON-riveted versions.

2) There were SIX prior ICU versions previously used, with the following part numbers, and these used a SEPARATE heat sink (that is, the module was not rivet to a heat sink, but bolted/screwed). These types require cleaning and fresh heat sink every couple of years.
       ALL of these are now obsolete (that is, they are no longer available from BMW).
       12-14-1-244-089---Non kick start version circa 1981 thru 1983
       12-14-1-244-191-- Kick start version circa 1981-1983
       12-14-1-244-226---Kickstart version circa 1983 and later
       12-14-1-244-481---12-14-1-244-482, from mid 80's up till about 1987-1988.
       12-14-1-244-477---Kickstart and non-kickstart version up till about 1988.
3) There were THREE heat sink design versions with (physical dimensional??) changes. ALL these heat sinks are obsolete, but may be available.
       12-14-1-244-087---First one, in 1981
       12-14-1-244-192---For kickstarter ICU's circa 1982/1983
       12-14-1-244-328---Post 1983 supposedly for use with kickstart or non-kickstart models.
Why all the changes? There are multiple reasons.
        A) The earliest design (089) internally, provided almost 2 seconds of time for coil current to flow while cranking the engine for starting. If the starter button was not depressed in time, the ICU would shut off the coil current off to prevent spark coil and ICU
              overheating.     There was a reset time needed which now and then caused starting problems. This created more than enough reason to call for change.
        B) There was a ICU ( 191 ) kickstarter version to delay spark current loss for up to 5 seconds to accommodate the slower use for kickstarting. Replacement choice required care to make sure the correct unit was fitted.
                 For this version there were some problems. It was superceded using the 226 later design circa 1984.
        C) There were other relatively short lived ICU's that followed, without any explanation.
        D) Another problem arose. Many of the later mid 80's models exhibited difficult starting, frequently firing only on one cylinder. Sometimes it would start easy, sometimes most difficult. The problem was eventually traced to the
                failure of the ICU to determine when it should fire for both cylinders all the time always on the power stroke. BMW crudely explained this as a loss of synchronization. Some users reported needing to place the KILL
                switch in OFF then back to ON position to rearm the ignition; then it would start. This problem was followed up with another redesign of the internal electronics of the ICU with a part number change again to 12-14-1-244-477
                for both the kickstart and non-kickstart models, obsoleting ALL prior versions of the ICU. Keeping the same part number, it was explained that if a new unit was installed, to make sure it had a turquoise paint color identification
                to insure the replacement unit contained the redesign. What they had done is to redesign the unit so that NO current would flow UNTIL the engine was rotated with the starter or kickstarter. That avoided the overheat problem entirely.
                The turquoise painted version was capable of handling the higher current required by a " souped up" much improved ignition coil.
        E) BMW also had problems with spark coil failure of the earlier single coil dual output from the early 80's onward. ( The TWIN black Bosch coils of the 81 thru 84 models are OK--work perfectly ). The plastic shell coils would crack and
             develop open or shorted windings. BMW decided to finally fix that problem and came out with a much improved single dual output coil for use with the later 80's thru end of production in 1995. They also provided a hotter spark, with a
              lowering of primary resistance to permit a higher current. The coil can be retrofitted to earlier models but would require the latest in ICU design due to the higher current need.   This complicated matters. It is necessary to use the 477
              suffix ICU part number with turquoise paint code, or use the very latest ICU (with the integral riveted heat sink--part 12-14-2-325-284 number ) which obsoletes ALL PRIOR VERSIONS. They do warn, that you must NOT use
              the updated coil on ANY of the older ICU's unless the ICU is coded with a turquoise paint dot. If you do use the new high power coil on an incapable older ICU, it will overcurrent the ICU and very likely cause it to fail.
Oak summarized thusly:
    There is only ONE ICU now available from BMW, ( 12-14-2-325-284 ) and comes with the riveted heat sink. The latest ICU should be factory equipped on all models circa 1988 and later. It is fully updated, all the gremlins removed and
    will handle the new high current hot spark single coil with dual output (part number 12-13-1-244-426 ). The new coil is supposedly equipped on all 1991 thru 1995 models. You may need to order some of the trivial mounting hardware to
    retrofit the latest ICU and coil to your machine depending on year and model. Now there is a word of caution involved with use of aftermarket ICU's. Remember, BMW took a long time to get their act together on ICU and coil updates. I
    have no idea what versions of aftermarket ICU's will work to perfection or demand and which may not. They all look alike and have the same terminal coding which apparently is standard but that is where the similarity may end. The
    internal designs have been upgraded a number of times. The question of aftermarket upgrades applicable or necessary for airhead use may be a mystery. I make no recommendation on aftermarket choices--that is your decision. If you do
   go that route, and the cost savings may be considerable, if it works OK you won !!

MORE NOTES:

1. There is often confusion about the coils used on early models. Some of the literature is wrong.....or misleading.
BMW coil 12-13-1-351-584, is Bosch 0 221 100 022, and was used on the /5, which is a points model.
BMW coil 12-13-1-243-452, is Bosch 0 221 101 003, and was also used on the POINTS MODELS, in the /6 and /7 era.
Both of the above coils are about 1.5 ohms each. It is possible that some literature will say that the coils are the same. For practical purposes, they do interchange...both being
1.5 ohm points coils.
BMW coil 12-13-1-244-142 is Bosch 0 221 100 028. Some literature will refer to 12-13-1-243-142 (note the 243, not 244) as the 1981+ coil with 0.7 ohms)...said literature
will or may show the Bosch number as 0 221 100 313.
The electronic ignition models began with MODEL YEAR 1981.
Because the MODEL year begins in September, some literature might show the -142 coil being used in 1980, or even on R65 models as late as 1982. Very confusing, and WRONG!

2. The canister bikes automatic advance had 120° dwell angle for 1979-1980 (points models), and from 1981 (electronics models) the dwell was 104°.

3. Electronic ignition models: The original troublesome gray colored twin tower single coil, which tended to crack and fail intermittently, usually eventually totally failing, but initially usually failing when damp, was the Bosch 0221500200 and was replaced by Bosch 02210500203, BMW 12-13-1-244-426 (that IS the NEW COIL). The troublesome coils were used in the 1980's, but NOT on all bikes until much later, and there were some on bikes such as the R45, R65, R80GS, R80ST. DO see later and also above, herein, about the MODULE changes and how they apply, or do not apply, to the updated later coil. The OLD coil was BMW 12-13-1-243-910. That coil is for pre-1991 engines, and the control units (Modules) with white or pink lettering are used with it. The very latest modules can be used with any of the coils!

4. The updated coil was black bodied. In the typical scenario of the beginning failure, drying and epoxying the coil cracks could be done as a very temporary measure BUT this may not work at all. The Oilhead coil has a low primary resistance, probably 0.35 to 0.50 ohm; and needs to be used with the proper module.

5. An Oilhead coil; or, TWO each 6 volt Bosch coils can used on SOME electronic module models in the early 1980's. For those Bosch coils, you MUST use the coils that have a LIGHTNING BOLT on the side, they have the correct electrical characteristics. The part number is 12-13-1-244-142. If substituting for the SINGLE two-tower coil, mount one coil where the original twin-output coil was. Use that coil for the LEFT spark plug. Mount the other coil towards the rear, under the relay bracketry, and use it for the RIGHT spark plug. Interconnect terminals 15 and 1 between the two coils. The remaining terminal 15 goes to the original green wire; the remaining terminal 1 goes to the remaining black wire. It is a good idea for the coils to be solidly mounted such that a good electrical contact is made to the metal body. These Lightning bolt coils are generally HIGHLY reliable, so long as one does not open circuit the spark plug outputs by foolishly lifting the spark plug caps when the ignition is on (this caution applies to all coil ignitions). You must also NOT ground the ignition coil, unless through a 5000 ohm spark plug cap. NEVER, EVER!....lift the spark plug caps with the ignition turned on!!!!!!

***NOTE: Some models had a red tower coil from around 1991, and they seem bulletproof. The red coil has a primary of 0.50 to 0.70 ohms. The original gray coil was 1.15 to 1.35 ohms.

The Oilhead coil was 12-13-1-341-978; the plug housing primary side is 61-13-1-459-515; and the connector for the housing is 61-13-1-459-516. The Secondary side (ignition cable to the coil) is 12-12-1-289-837, connector for the coil is
12-12-1-705-656...needed because the cable can't be screwed into the plug. Add a rubber cap at the coil. Bosch does have a part 0 356 250 033-000 plug and it CAN have the cable screwed-in.

****It is possible that some of the numbers I use are not in the BMW North America ordering system, but they exist.

6. BMW updated the module with some internal timing changes inside that 'black box'. Don't use the new black coils with a module with white or pink lettering.
***Additional information will be found at ignitionsingleplug.htm see #7 for instance.

7. Suppressors (Spark Plug Caps): CAPS were metal sheathed from 1970-1976, 1000 or 1200 ohms nominally, depending on which piece of literature you are looking at, and, in any event, the tolerance is officially +-20% (if they are 800 to 1500 ohms, I would be satisfied), and from 1977 were 5000 ohms nominally. ALL points bikes can use 1000 ohm caps, the NGK caps are preferable to the metal types. The electronic ignition bikes (1981+) MUST have 5000 ohm caps, using the BMW cable/caps.....NGK 5000 ohm caps are also OK. NGK numbers for 1000 ohm caps are LB010F; for 5000 are LB05F. They make 10,000 ohm caps too, so be SURE to ACTUALLY measure them, you MIGHT just confuse the part numbers for 1K and 10K. Some R65 had metal caps molded to the cable, and were 5000 ohms.

8. There is another article on this website with extensive information on spark plugs AND all the NGK caps information, etc.
sparkplugs.htm

For the 70-80 points Airheads, Dyna had an Ignition Booster....and this could be used with SOME dual plugging coils; like DYNA coils.

Many years ago, the original Dyna D35-2 system was NOT a wasted-spark system. They used DC1-1 green 3 ohm coils on the dual plugged conversions, and the sensor plate had THREE wires. Each cylinder could be set separately with a timing light. Since this was NOT a wasted spark setup, each coil fed ONE cylinder (that is, each coil fed the top AND bottom spark plug on ONE particular cylinder). Dyna has not offered this D35-2 in many years. Now, what is available is the D35-1, wasted spark model. The D35-1 has TWO wires at the sensor plate; and uses the 1.5 ohm coils...which are brown, or orangey looking, and are series connected. Timing is set with an ohmmeter or test light, as you rotate the engine by hand, so to watch the magnet location, to know what side sensor you are adjusting.

The popular Dyna III model D35-1 was for the 70-78 Bosch coils, or, Dyna coils....and the wiring is; to the Dyna box: white, left cylinder; red, right cylinder; Black is ground. The other red goes to +12 at ignition switch and to the left coil +. The coils are interconnected by a jumper, same as on original BMW, same numbers at coil primaries, if using those coils. The right coil (-)is the one with the brown wire from the Dyna box.
Unconfirmed: Dyna III uses UGS3040T Hall devices
If you have a Dyna III, either type 1 or type 2, Dyna has some simple troubleshooting information at:
http://www.dynaonline.com/skins/downloads/instruct/Dyna3TSG.pdf

Dyna coils are color identified:
blue coil is 0.7 ohms;...used on 92-95 airheads; secondary is 11.5K
reddish orangey or brown coil is 1.5 ohms, dual tower for dual plugging on the D35-1
gray coil is 2.2 ohms and 14K secondary
green coil is 3.0 ohms, for dual plugging on the D35-1.
black coil is 5.0 ohms, 17K? 14K/
brown coil is 1.5 ohms, 14K secondary, for 81-92 stock airheads.

If using the Dyna TWO wire sensor setup, the two coils will be in series connection for the primary windings. If the Dyna sensor setup is the three wire type, the coils are not connected that way, but are independent. If either of the red or white hall effect wires are touched to ground, you should get an ignition spark output.

Watch out for improper Dyna sensors insulation; that is, broken wires at the sensor plate where they exit the epoxy, and for coils shorting a primary to ground when hot. Use NGK 1000 ohm spark plug caps.

The old black box Boyer, the Mk3, can be used with or without resistor spark plug caps. The Microdigital (red box) is sensitive to RF interference, so the 5000 ohm spark plug caps are required. The unit won't be injured if you don't use these, but the microprocessor will go crazy and upset the timing. A URL for troubleshooting the Boyer MK 3:
http://www.oldbritts.com/boyer_testing.html

That URL has a schematic diagram of SOME innards, operation, wiring, spark curves.

Note!....the early Boyer ignitions have been known to cause rough running problems, and the bike being hard to start. This is usually from low battery voltage, and SLOW cranking speeds, both of which are disliked by the old Boyer. The early Boyer models also have an ignition curve that does not well match the Airhead engine requirements. In particular, the early Boyer had an ignition curve that was slow rising and kept rising, there was no practical limit....the ignition would continue to advance with increasing RPM. Many are in use, however, on Airheads, with no problems noticed.

The Boyer-Bransden ignition has been updated. The Boyer has always been a good ignition to consider when the tip of the pre-1979 camshaft was broken off. Now, with the new model with the updated ignition curve (ALSO available in a modified version for dual-plugging installations) (and supposedly now works OK with a slightly weak battery, low voltage that is, during starting), there is less reason to not recommend it.
www.rockypointcycle.com
Below is the Boyer-Bransden Microdigital Electronic Ignition advance curve, courtesy of www.Boyerbransden.com and obtained from Stan Smith when he owned rockypointcycle.

YOU ARE ONLY 1/3rd OF THE WAY DOWN THIS PAGE...WHAT FOLLOWS IMMEDIATELY IS A SKETCH. DO NOT STOP HERE...LOTS MORE FURTHER DOWN AFTER THE SKETCH!!

Oilheads and classic K bikes:
Information on the module and Hall sensor in the article you are reading has similarities to the oilheads and K bikes.

You may be interested in a how-to article, illustrated, which was for a R1100RT, but is VERY similar to a K bike:
www.ebbo.org/2av54.php

>>>>Some folks who are overhauling/rebuilding canisters: <<<<<

Motorrad Elektrik (256) 442-8886     www.motoelekt.com

OAK Okleshen AskOak@aol.com   Top quality work from our own Airhead Guru. ASK about any backlog!!!

Rebuilds ignition canisters:  Dwight Small, 1437 N. Denver Ave. #298, Loveland, CO 80538; (970) 214-2610; rbike.ignition@gmail.com

THE FOLLOWING SECTION IS IN PROCESS, IT IS NOT COMPLETED NOR CHECKED FOR ACCURACY. Furthermore, things may be out of order.

NOTE!!! It appears that there is more than one style of plates/sensor setups. The mounting plate may have a second plate affixed, and then you can't drill one rivet and use screws and nuts. One rivet can be ground down from the top plate. The new sensor comes with the mounting rivets imbedded in the plastic housing. You won't likely find a way to flatten the blind rivet BETWEEN the plates. You can remove those rivets, and use the holes for your own rivets. Make sure the sensor is flat and flush with the plate...it is a bit tricky, clearance is tight for the rivet tool, although you can modify one.

Disassembly (I highly suggest you make notes on what goes and fits where, as you disassemble the canister):

NOTE:   Some screws may be quite tight. You need a PROPERLY fitting screwdriver. Don't bugger-up things!
Remove the pin that holds the coupling to the shaft....at the end that goes into the camshaft.   You will need a small diameter round drift.   Be careful doing this, some are in very tightly, some are not. If quite tight, you may want to do this with a press, or make up something so as to use your vise. Do NOT bugger things up. In any event, support the shaft.    You will find some shims and a washer.
Remove the cap (Phillips type screws).  That cap normally has a spongy material on the inside. It tends to deteriorate. Remove it all. That spongy material can make a mess inside the canister once it moves all about.   Remove screws for the bearing plate, and remove the plate; noting how the plate fits.   Note the big snap ring, and how it fits in a groove.

Remove the C clip. Remove the three outside screws. Looking inside the canister, notice the 3 tabs that those 3 flat screws fit into. Mark a tab and can, so you replace them later in the same position...(if you want to), but the tabs are not equally spaced, so this is moot. Now remove the screws.

The flat screws hold the retainer. That fits the snap ring only in one direction....a keyhole in the retainer matches a protruding stud on the snap ring. Note that how the big snap ring fits, where its open end is.

Remove the plastic rivet from the wire strain relief. Note that the plastic strain relief has a tit, you have to pry or pull it out....once out, the strain relief moves in the slot easily.

The coupler has a spring thing wound around a groove. Pry an end loose, and remove from coupler.....you now need to remove the pin which is now visible. You need to improvise something that will not injure anything, to remove that pin. Do that now.

Use a soft hammer to move the shaft through and enable removing the contents, do this a bit at a time with the plastic wire strain relief...back and forth. Remove slowly, don't use a lot of force, and write down what you see about ....ALL about the many washers, etc., you find.

NOTE! BMW does not sell canister parts. I think Motobins in UK sells the springs for the advance weights.

It will be clear to you to remove an E-clip, and another snap ring, which hold the 'shield' in place. Note the pin, locating the advance and shield. Don't mess up that shield! Don't loose the small location pin either. This stuff is expanded upon in the next paragraph.

NOTE regarding the Sensor, if yours has failed: Once the canister is basically disassembled, you need to remove the 'vane' without injuring it. The 'vane' is between TWO C rings. Remove the top C ring, and remove the pin (very small). Be careful. You will have to improvise something for this vane removal. You can now remove the other C ring, and the 2 flat head screws on the sensor bottom. The sensor is riveted and you have to drill that out....replace with a steel pop-rivet or nut/screw.. Use a Dremel or similar or?? to grind off the rivet. See note at beginning of this canister section, about the dualplate and blind rivet models. Cut the wires on the old and new sensors, so you can connect them and insulate them (shrink tubing). Be cautious about the re-riveting; and keep things in proper shape. If the wires are long enough from the sensor, splicing can be done outside the canister. I prefer them connected inside, and the wires kept short enough to avoid fouling on moving parts. The triggering magnet part of the sensor and is retained by an E-clip and a snap-ring. The snap-ring does not hold the rotor in place, the PIN does. The snap ring keeps the pin in place. The PIN locates the magnet, with respect to the shaft. Don't lose that pin. Don't mess up here. Put the unit over a common socket of correct size, all on your workbench, hit the shaft with a SOFT hammer (plastic?).

It is very important that the parts be very well cleaned, and if need be the shaft burnished in the ATU area. You need to use some judgment and have some experience here. Sticky ATU problems show up as increasing idle speed USUALLY when the engine is quite hot....as the parts expand from heat. The weights are on a Teflon thing, don't oil the Teflon unless you have an oil that is exceptionally slow in evaporation and probably contains Teflon;....I use a Teflon grease in that area.

When doing the final assembly of the canister, pay attention that the shaft continues to rotate freely, in particular as you tighten the side screws. Ken Lee had one that "dragged the edge of the rotor with the bottom of the sensor housing between sensor and magnet" (his words). He suggested cutting a small relief slot with a Dremel tool for clearance.
When mounting the canister to the engine, install a new O-ring at the base.

NOTE: The sensors vary somewhat in how they look or are mounted. Pay attention to what you are doing. The canisters that have a lower plate and upper plate assembly that has the blind area, can be worked on, with some thought. You could drill a couple of access holes for a riveting tool. The Classic K bikes use two of the same type of sensors, just not in a canister! Oilheads are similar.

Modifying the canister for dual-plug conversions:
This is, or is not necessary, depending on who you talk to.

One point of view is to use an IDLE ignition timing of OT, or very slightly advances from OT; and leave the canister advance unit stock. Some who have this point of view may recommend bending the advance ears outward just shy of touching the case inside wall. That adds a bit of maximum advance. I have also modified the weights/stops for additional advance. It is not a must.

Another point of view has it that the advance should have its total amount shortened a bit. This point of view is held by some who, even on the old non-canister models, time the engine at the normal S mark, but restrict the total advance. An article posted by Pete Serrino recommended using one or more layers of shrink tubing over the advance weight stops. He did not specify the type of tubing, but said that one layer of tubing shortened the curve by 2° crankshaft; and he uses 2 layers for dual-plugged 336 camshaft bikes, and 3 or 4 layers for 1000 cc 308 camshaft bikes; and one layer less on 800 cc bikes. I honestly do not think that restricting the advance range is really necessary, and, in any event, I feel it depends on many factors, including the compression ratio in use. Certainly for very high performance engine modifications, one might want to delay the maximum advance or fiddle with the maximum. I certainly agree with what Pete said about one modification: Drilling the weights with a 1/4" hole about 2/3 up from the pivot point, and, a 1/8" hole close to the first hole, will move the rpm up 500. I prefer stronger springs, but, like Pete, I never found any, although some Porsche ignition springs were quite good enough.

Revisions:
09/16/2002: wire color code, notes, links fixed and verified; red emphasis areas. Additional changes to clarify meanings.
01/25/2003: additional minor clarifications and cautions; add Newark part number for the Hall element; note on canister/high idle; minor clarifications and grammar and typos of little importance.
02/01/2003: points parts number; gray coil information; information on Dyna and Boyer
to 02/05/2003: module timing and color coding information; some rearranging and editing of little consequence; other modules from cars; add suppressors information; information on dwell; canister shaft swelling; Bosch module versus SYSTEM, which I've colored, just above the sketch, as green
05/15/2003: minor clarifications, more information on coils; fix hyperlinks operation
05/15/2003: correct .htm, I upper case must be i lower case
07/13/2003: hyperlink for #2.
12/05/2003: greatly expand information on substitute modules
02/03/2004: expand information on modules and coils slightly in preparation for information to be obtained in future
03/09/2004: update slightly, not uploaded
10/31/2004: Add several URL's; edited entire article for better clarity.
12/30/2004: expand information on alternate sources for canister points
04/09/2005: add note at very top
05/11/2005: Electronic module and coils information from OAK, from Airlist; slight revision here and there due to that.
03/22/2006: Add Stan Smith, Rocky Point cycle as source, and Transpo number
04/13/2006: Correct hyperlink to ...oldbritts....
05/30/2006: updated things on the new modules and coils, for clarity
11/16/2006: Minor editing, and updating/expanding information on RockyPointCycle
11/23/2006: Add another source for the Hall elements
11/27/2007: Technical details updating. Modify testing and wiring notes. Stopped major updating, awaiting when I can personally overhaul a canister, step-by-step, making sure that section of this article is clear to anyone.
01/12/2009: Add Boyer curve and change my recommendations and feelings about it. Fixed some typos, expanded some things
to improve clarity.
02/05/2009: update Dwight Small's information
02/08/2009: Remove a few spaces, add note about being only 1/3rd way down the page
04/30/2009: Minor correction (clarifications really) to ICU pin functions
11/12/2009: minor updates; primarily was removing outdated links, and do some clarifying.
01/01/2010: expand, slightly, points amplifier section.
02/16/2011: information on faulty 1970-1978 points.
03/01/2011: clarify information on hard starting module problems
05/06/2011: Add note regarding motorcycle module locations and which are to be re-coated, which not.
05/11/2011: Completely revise this article for clarity, eliminating duplications, expanding commentary on the coils and modules, clarifying many issues.
05/15/2011: Add one troubleshooting link to Dyna information
06/07/2011: Add + and - symbols to the test with connector and voltmeter and 10K resistor sketch. Add more information on how to test for ATU problem with high idle rpm.
07/29/2011: Clarifications in NOTES section
08/29/2011: Add note about 3 pin connector being available at car salvage yards.
09/21/2011: correct Dwight Small's information; re-arrange where aftermarket rebuilders are listed
11/06/2011: minor clarifications on modules.
01/11/2012: add a bit more to the old points commentary
03/20/2012: Add this section: How to test for a bad Hall element in the canister: