Is it likely?

[Ed Miller]

I have read that some later or aftermarket coils aren't very compatible with the original ICU, but it hasn't struck me as a very conclusive argument.  That means that I can't remember it exactly, but it didn't really persuade me.  

I have an aftermarket ICU from Rocky Point (about 35 bucks) and the BMW replacement coil for my R65 and it all seems to be working great.  I'd guess it's only been about 15,000 miles though.  I still have my stock ICU as a spare as it did not turn out to be the problem I was chasing.

[montmil]

I have read that some later or aftermarket coils aren't very compatible with the original ICU, but it hasn't struck me as a very conclusive argument.  That means that I can't remember it exactly, but it didn't really persuade me.  

I have an aftermarket ICU from Rocky Point (about 35 bucks) and the BMW replacement coil for my R65 and it all seems to be working great.  I'd guess it's only been about 15,000 miles though.  I still have my stock ICU as a spare as it did not turn out to be the problem I was chasing.

Ed, I also recall reading similar threads about the incompatibility of certain automotive-style coils as BMW MC replacements. First time I pulled the fuel tank on my recently purchased 1983 R65, I found two blue Bosch ignition coils hose-clamped to the frame. Quite the ghetto install, it was. Bike ran fine but I promptly replaced them with a new Dyna. Talked with Rick Jones about the odd install and he agreed that the Dyna was, by far, the better idea.

Also, the Bosch ICU component -located just aft of the coil- is a commonly used bit on several German autos and can be purchased for far less money than the parts box branded BMW. I have a cross reference list... somewhere.

Cuzin Monte  

[Justin B.]

The ICU looks the same as on my Volvo 240 as well.  As an aside, I'm pretty sure my '81 R100RT has a pair of "automotive style" coils in what looks to be a factory configuration.  I'm thinking that if the load that the coil presents to the ICU is the same then the ICU probably won't care (or know) that a "BMW approved" coil isn't installed...

[Ed Miller]

snip I'm thinking that if the load that the coil presents to the ICU is the same then the ICU probably won't care (or know) that a "BMW approved" coil isn't installed...

That's what I think, too.  I can't remember who was making the argument; I want to say Oak on the Airlist but I don't know.

[Justin B.]

I remember discussion about the "new" stock coil needing a "new" ICU due to the new and improved coil not matching up with the older ICU.  But, people who did not change ICU have never had any problems that I know of...

[Bob_Roller]

I have the original ICU on my '81, and I ran the 'upgraded' red and black OEM coil for 11 years, before it quit, and I have been using the Dyna 'brown' coil for about 4 years now without ant problems .