1981 R65 Charging System & Ignition

[tlangman4]

Hi All -

As I begin to address the long list of work that needs to be done to my recently purchased ‘81 R65, I realized that I failed to think about both the charging system and ignition. My last airhead (and all 3 of my previous airheads) were all ‘70s models of 247 engine vintage. This is my first 248/1.

Two questions-

1) Is the Bosch electronic ignition on this model the same bean can used on 247 models of similar vintage? Any difference’s
2) Is the charging system as marginal as that on ‘70s 247 models? I recall my ‘73 R75/6 being borderline for daily use.

Thanks for any feedback!

Tom

 

[m_stock10506]

Don’t know about the bean can. But, the /5 charging system put out about 180 watts, the later Airhead systems put out 240 watts. Lots of folks do the upgrades to higher output systems, but the 240 w system is reasonably capable unless you’re doing stop and go riding which won’t recharge the battery.

 

[20774]

The ignition sensor for a 1981 R100RT is part number 12112413906. From RealOEM, that part covers many models:

http://www.realoem.com/bmw/enUS/par...0_RT&mg=12&sg=12&diagId=12_0776&q=12112413906

 

[26119]

Hi All -

As I begin to address the long list of work that needs to be done to my recently purchased ‘81 R65, I realized that I failed to think about both the charging system and ignition. My last airhead (and all 3 of my previous airheads) were all ‘70s models of 247 engine vintage. This is my first 248/1.

Two questions-

1) Is the Bosch electronic ignition on this model the same bean can used on 247 models of similar vintage? Any difference’s
2) Is the charging system as marginal as that on ‘70s 247 models? I recall my ‘73 R75/6 being borderline for daily use.

Thanks for any feedback!

Tom[/QUOTE

Airhead charging systems are sufficient for a stock bike ridden more than just stop and go. They are known to fry the diode boards due to a decayed ground wire. A cheap and easy precaution is to add another ground wire from the diode board to the case. Or carry a spare diode board and ground wire. Time is the culprit, corrosion or mechanical failure. I replace the stock systems $300 and sell the used parts $100 to to people who demand vintage parts.

 

[boxermaf]

I would check the diode board as a number of them from this period still have various failures from poor solder, heat, wear&tear, etc.. I got a new aftermarket diode board from Rick at Motorrad Elektrik - or you can probably get the same one from EME. Check all the wires, replace any that are cracked or corroded. I wasn't getting great charging in my 82 R65LS, and it was a flakey diode board that was the primary culprit. The aftermarket ones are quite well designed - won't charge more as that is limited by alternator output.. but you WILL get the full capability of your alternator with it. Another common point of failure or weakness in charging is the older (silver can with red tape) voltage regulator. These work pretty well when they work, but generally these are beyond their lifespan now. Again, there are ones you can get from Motorrad Elektrik or EME that will allow slightly higher output voltage (but again, doesn't increase total charging power... just ensure you get the most out of what you have).

The bean can from the 1981-models are all basically the same. They use Hall Effect sensors with centrifugal advance mechanism. The bean cans from pre-1980 are the "points-in-a-can" type.

 

[happy wanderer]

The best way to find out _exactly_ what you have is to go to RealOEM and punch in your VIN number. This will always get you to the right bike, right year and configuration of your specific model for your specific country.

The R65 had points in a can ignition up to 09/80.
12 11 1 243 441 DISTRIBUTOR (to 09/80) 1.34 1 $637.11

After that it used the Hall Effect
12 11 1 244 088 IGNITION SENSOR 1.31 1 NA

They don't make them any longer but recently introduced a replacement plate for the vital part that failed which was the sensors themselves with this part:
121112440881 REPAIR KIT FOR IGNITION SENSOR 0.26 1 $329.99

If you are handy with small parts and have some soldering skills the sensors are available and you can replace them yourself at considerable savings to the BMW replacement plate. I have two; one in my RS and one in my G/S. I take them apart periodically when the idle starts to hang up and lube the advance mechanism which gets sticky in all that heat down there over time. Note that the Honeywell AV54 hall sensors that were used originally are no longer made by Honeywell. But there are some other manufacturers that still make them, mostly in China. I can't speak to the quality or longevity when compared to Honeywell's product which seemed to last forever as I have not needed to replace one yet.