Is the R65 ignition system really unreliable?

[steve_wicks]

Since discovering this forum I have become paranoid at the thought of my bike ('81) suddenly stopping with a dead ignition.

My bike has an aftermarket 2x coil system and although I can see the ht leads need replacing I don't know what has been done.

Is it so bad, are there warning signs, should I stop using it in case it fails to proceed and I get abducted away by rabid head hunters?

[montmil]

You may get better odds with being struck by lightning.

Do the maintenance chores to stack the odds in your favor, ie:
• Heat sink paste renewal for the ICU,
• Always disconnect the battery neg lead before removing front engine cover. Easy to forget, Simple to fry the diode board as power to it is always hot,
• Maintain the battery in top condition,
• Talk nice to your bean can.

The electronic ignition on the 81 and up R65s is almost identical to my 1986 VW Cabriolet. The distributor has the same Hall sensor and the ICU is identical to the bike's.

I have had a Hall sensor fail with me about 35 miles out in the boonies. It was just bad karma.

Don't sweat it. Ride the bike and enjoy it. My emergency kit includes a cell phone and a credit card... both fully charged.

Monte  

[Bob_Roller]

If you are not the original owner, the only things that I would look for, is some 'handy work' of some previous owner.

Like wiring put together with twisted wire and electrical tape, wire nuts etc.

I don't know what the resistance of the two coil system would be, maybe someone here can say for sure.

But condition of the coils and ignition leads are about the only things you can really check for sure.

Checking the electrical connections for corrosion.

I don't know if that is a real issue in your area, only reason I bring it up, is that you are on a salt water coastal area, and usually the conditions are just right for corrosion in areas like this.

The ICU, and the Hall sensor are usually components, that either work, or they don't, they are not known to give much warning of an impending failure.

If you are really concerned about them, only thing to do is replace them.

[Justin B.]

What do you mean by "aftermarket 2 coil ignition"?  Does this system replace the ignition pickup and ignition control unit?

If yours still uses the stock components they are not that prone to failure but are a bit picky about modifications, especially in the coil department.  It is reported that the Hall-sensor can be fried by cranking/running with a plug wire off and not grounded, also if the coil primary windings are not the proper resistance.

[montmil]

...What do you mean by "aftermarket 2 coil ignition"

This question goes directly to the recent installation of a Dyna coil on my '83 R65.

When purchased, the bike had two Bosch 6V coils hose-clamped to the frame's backbone. The original BMW coil wiring was installed, IIRC, with one of the two 14/16 gauge wire harness female plugs going to one of the terminals on each coil. There was a DIY jumper that connected the remaining two open male spade connectors on the coils.

Add another shout out for Rick Jones and Motorrad Elektrik here. [smiley=thumbsup.gif] While talking with Rick, I mentioned this set-up and he strongly stated that with the incorrect resistance of the Bosch coils, there was a real danger of ruining the ICU.

I did not start the bike again until the ICU heat sink paste was renewed and the Dyna coil installed. Yes, the bike ran with the twin coil rig but this begs the question... for how long?

Monte

[steve hawkins]

Interestingly enough my 1982 R100 has electronic ignition and a pair of original equipment Bosch coils as you would find on the earlier bikes.  I was expecting to find the old 'cracking' grey twin output coil.  The coils fitted to my bike are OE and were the original fitment.  One of them has even broke the frame mount.

My points system 1979 R65 is running a second hand twin output K100 coil.

Both are running fine.

The only comment I have on the 'Bosch Blues' usually fitted as a cheap replacement to the original 6v coils, is that they are longer and heavier than the originals.  If the originals can break the frame moints then the Bosch Blues certainly will.  And did on my R65 - which is why I removed them.

Cheers

[Justin B.]

Steve, my '81 R100 also has twin coils and the rear mount had snapped so it is now tie-wrapped to the frame!  Some day I'll properly fix it.  

I don't believe in a blanket statement that "if you have two coils you're gonna fry your ICU" as the factory apparently did it that way in the beginning.  As long as the coil resistance is correct the ICU is not going to know the difference.  I am thinking the twin coil probably came about more as a cost reduction and weight saver than anything performance or reliability related.  It wouldn't surprise me at all if the beancounters had them design in the crack feature in order to boost spares sales...

[Bob_Roller]

By the way Steve, great looking bike !!!!

[montmil]

Steve, my '81 R100 also has twin coils and the rear mount had snapped so it is now tie-wrapped to the frame!  Some day I'll properly fix it.  

I don't believe in a blanket statement that "if you have two coils you're gonna fry your ICU" as the factory apparently did it that way in the beginning.  As long as the coil resistance is correct the ICU is not going to know the difference.  I am thinking the twin coil probably came about more as a cost reduction and weight saver than anything performance or reliability related.  It wouldn't surprise me at all if the beancounters had them design in the crack feature in order to boost spares sales...

Please check my post once more... "he strongly stated that with the incorrect resistance of the Bosch coils, there was a real danger of ruining the ICU.

There's also additional thoughts floating around several well-known BMW sites regarding incorrect resistance Bosch coils being attached to the bike's ignition system and creating problems.

Now that there are also counterfeit look-alike non-Bosch ignition coils circulating on the market, it would be important to know and check for the proper specs of aftermarket coils.

The bike ran fine but I wasn't too pleased with the non-factory installation. The install actually kept the fuel tank from seating fully on the forward rubber tank mounts. Something not right there, too.

Monte

[ambrose78]

I reckon after 28 odd years of being reliable, it's probably reasonable to refresh the ignition system. Then it'll be reliable for another 28 odd years.

Along with what Bob_roller and Montmil mentioned for, piece of mind preventative maintenance replace the hall sensor, (it's the only time consuming hard to get to bit to change. they seem to just crack and stop working with age after many many hot cold cycles), freshen up the heatsink paste on the ICU and carry an ICU in the bike kit. (or replace the existing one with a new one and carry the old one as a spare JIC)

While you have the soldering iron out to refresh the hall sensor, get a pack of 1A diodes and replace the odd accessory diodes to replace the neutral light diode and the hazard/indicator circuit diode. Although they won't affect the running of the bike like an ICU or a trigger sensor, it is quick and easy to fix if you are in the soldering mood.

[steve_wicks]

Right, that stupid Hall sensor thing will evidently cost me almost as much as the bike is worth and then add the 'correct' coils makes it a stupid project.

So, rather than risk breaking down and being stranded in some remote (read dodgy) area I'll sell it before it breaks down.

Really annoys me beacause I've fitted new tyres and new clutch & main oil seals & things to fix the oil leak, but I've got to have reliable transport and that's why I bought a BMW .

[nhmaf]

EVERYTHING that is more than 25 years old may just not work quite as well as it used to!  The main thing with these BMWs is that they are user-serviceable, and all the major bits are designed to last a long time.
It is still much easier buying parts for these bikes than it is for 25+ year old japanese bikes.  And, even the 25+ year old BMW cars have their quirks, too.

Don't lose faith, it seems like you've done alot to get the bike up to snuff, but you're nearly there, and once you've hit the "plateau" it will be just as serviceable as when it was new.   Again however, while it was a reliable bike for its original time period, it isn't as maintenance-free or uber-reliable as a modern day machine could be.

I wouldn't bother to replace the hall sensor in the bean can unless it was acting up or I was preparing for an "epic" ride like from Canada down to South America or something, where much of the time I wouldn't be able to readily find spares parts or a safe place to stop away from banditos.   But, that doesn't mean that I won't keep my eyes open for one and buy it if the price is right, 'cuz it is very likely at some point in my life I'll end up replacing one.  The handy thing about many of the airhead models is that there are alot of parts that are interchangeable, so if you just buy ANOTHER BMW airhead of similar vintage, you'll have a full set of spares for most anything that can wear out !
 

[montmil]

For the hassle factor of replacing just the Hall sensor, I might suggest picking up a spare to take along. They are rather small-ish.

Noticed a very reasonably priced functional bean can on the IBMWR site.

http://www.ibmwr.org/market/

Monte