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Hi, I am Roland and the new owner of an R 65 LS I have already owned a 2012 R 1200 R

R

rgarlinghouse

New member
Now that I have recently purchased a 1984 R 65 LS and have been riding a bit I find a problem, It runs fine for about 50 miles, but after that it starts backfiring or stops running. I have checked the fuel flow and it is OK. When it acts up the tach goes to zero even though the engine is still turning over. My thought is that the coil is failing and that is what is giving me the ignition failure. Can anyone tell me if the tach gets its input from the coil as that would confirm my suspicions. Also where are the best places to order parts for these older BMWs? I love the way this old bike handles. My prior BMW experiences have been with 2012 and later R1200Rs and 2016 R1200RS, so I'm a bit clueless on the care and feeding of these older animals. Any info would be very much appreciated.
Thanks, Roland at regarlinghouse @msn.com or MOA @ 213339. Ride Safe!
 
Hi Roland, welcome from Newfoundland. I have an '82 R65 LS so I know your ride. I can't say for sure but when I've had some similar issues it was one of the fuses coming loose. They're easy to get at under the seat, might be worth having a look.
 
Welcome to the forum, Roland! As for the issue after riding the bike for a while, I would first look at renewing the heat sink paste that is between the ICU and its mount. If the paste is old, it might not be transferring heat as well as it should, which then shuts down the brains for the ignition system. I do believe that the tach on all Airheads got their input from the coils...the rate of the field collapsing is indicative of the engine RPM.

What part of the country are you in? Maybe you're near some BMW outfit for parts. I tend to go to my dealer for most things. But I've heard that MaxBMW has a good reputation for working with Airhead owners. Bob's BMW is also a good source. Bench Mark Works tends to focus mostly on pre 1970 but they do work on and have parts for Airheads. Beyond that, for specific items it may be worth dealing with some of the independent mechanics that are positioned around the country.
 
skibum69 said:
Hi Roland, welcome from Newfoundland. I have an '82 R65 LS so I know your ride. I can't say for sure but when I've had some similar issues it was one of the fuses coming loose. They're easy to get at under the seat, might be worth having a look.
Click to expand...

Hi skibum69. Thanks for the tip. I will make the fuse check as suggested. I hope the fix is as easy as that.
 
20774 said:
Welcome to the forum, Roland! As for the issue after riding the bike for a while, I would first look at renewing the heat sink paste that is between the ICU and its mount. If the paste is old, it might not be transferring heat as well as it should, which then shuts down the brains for the ignition system. I do believe that the tach on all Airheads got their input from the coils...the rate of the field collapsing is indicative of the engine RPM.

What part of the country are you in? Maybe you're near some BMW outfit for parts. I tend to go to my dealer for most things. But I've heard that MaxBMW has a good reputation for working with Airhead owners. Bob's BMW is also a good source. Bench Mark Works tends to focus mostly on pre 1970 but they do work on and have parts for Airheads. Beyond that, for specific items it may be worth dealing with some of the independent mechanics that are positioned around the country.
Click to expand...

I live in Fort Myers, FL so it does get warm down here. The local BMW dealer does not work on airheads. I recently discovered MaxBMW and they have a great website. Your suggestion on a heat transfer issue makes a lot of sense since it runs great until it has run for at least an hour and then the problem arises. I will get going on that. Can you suggest a source for the heat sink paste? Do you know of any airhead mechanics in Southwest Florida? Thanks for your help.
 
I would have suggested Radio Shack for heat sink paste, but don't think that's an option anymore. Certainly any electronics house can supply you with a tube of the stuff.

Not sure exactly what SW Florida is...Tampa? I've heard of a number of Airheads living around there. You could check the Anonymous Book to see who might be around you. A few months ago, the Airheads Beemer Club mentioned a TechDay up in Homosassa. You might also check the Airheads Beemer Club website and join that group as well.
 
There are Radio Shacks in Florida (at least according to their website), and they still show their silicone-based thermal pucky as p/n 2760418, $6.95/tube.
Computer parts supply shops also sometimes have thermal paste; I've used Arctic Silver when installing microprocessors.
GC Electronics (in Illinois) still carries three types and can be mail-ordered. http://www.gcelectronics.com/index.asp
 
If you haven't already join the Airheads club. I know for sure there are a bunch of really nice members in FL who have generously helped me with mine. Good bunch who run a bunch of tech days and other events. If you talk to Kevin the Air Marshall tell him I sent you!
 
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