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Old 04-20-2015, 07:19 AM   #1
kentuvman OP
kentuvman's Avatar
Joined: Jun 2013
Location: Minnetonka, MN
Oddometer: 12
Ignition Problem '82 R65 LS

Your experience and input in helping me solve a problem is appreciated:

I'd restored a non-op R65LS and some of the electrical component replacement items were a new black Bosch coil as Grey OEM (crack-o-matic) unit was cracked. I'd upgraded the voltage regulator to the unit from Rick Jones. Bike has new plug wires and NGK caps. New battery.

The initial issue was I'd be riding along at cruise and get a little "blip" like a sudden power loss - just like a millisecond and bike kept on running.

About a year ago, while riding the bike just started backfiring, etc, tach needle was swinging wildly and bike died, would not re-start and a friend came with his truck to load the bike and take her home. From what I'd read, it seemed like the Hall sensor in the bean can had failed and that was about the only part of the bike I hadn't gone through.

After replacing the Hall sensor, bike was much easier to start and I took her for some longer rides without incident.

This season, the bike has died at least twice - on one occasion she died but re-started and I was able to get back home - I removed front cover and checked connections where bean can plugs to wiring harness and all was good.

This weekend a friend and I went for a ride and about 25 miles into the ride, the started sputtering and backfiring. Up until that moment, she was running strong! She died and after letting her cool down, she started again. Never made it home - the same friend, a good friend at that, got his truck and we brought her home - again.

I described the situation on MOA Forum and shared the only thing I had not checked was the Ignition Control Module - I explored online and read a post by Anton Lagardier about the older ICM's with white lettering not being compatible with the newer black Bosch coils - I read the newer ICM's have a shutoff - here's what Anton says:

"Around 1991 the black coil (BMW 12 13 1 244 426, Bosch 0 221 500 203) was introduced. This coil has a 0.5~0.6 Ohm primary resistance. The ICM was simultaneously upgraded so that it cut off coil power after 1.2 seconds of inactivity, to prevent overheating damage to the coil, and presumably was rated to handle the higher current draw of the new coil. These ICMs have turquoise lettering (shown here) rather than white or pink. BMW recommended against using the new coil with an older ICM lacking the time cut-off."

I went ahead and ordered a new unit from Euromotoelectrics. I'm 99.5% confident that the bean can is functioning properly, and I do have a spare can (that was not with me when bike died).

I've been through the wiring harness and all connections are clean and solid (unless there's a broken wire I don't know about). The valves are set correctly, the carbs are set properly and the plugs look great! Petcock valve works as it should.

Wondering if any of you have had a similar experience and what the RX was - I did test the coil by removing each plug, grounding it, turning on ignition and switching kill switch on and off - there is a spark on each side.

Trying to figure this out so I can go out and take longer rides with confidence that I've solved the problem.


Ken in MN
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Old 04-20-2015, 01:21 PM   #2
Studly Adventurer
Joined: Feb 2013
Oddometer: 802
Does sound like the later type low resistance coil that you are using has caused your ignition module to overheat because it will have been pulling at least double the current of your original 1.5 ohm coil.

The new unit from Euromotoelectric should be OK though as that has built in dwell control which will limit the current.
A man haunted by a fixed idea is insane. He is dangerous even if that idea is the idea of justice - Joseph Conrad
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