Airheads Beemer Club Forum - Recent Posts

RE: Signal lights R100 RS

Richard W — Thu, 29 Oct 2026 13:39:32 +0000

Running all standard bulbs, I'll compare the rears I just put in to the front ones to see if they're different.

There are many "standard" bulbs. Make sure yours are all numbered 1156 on the base (also listed as BA15S or P21W). These single filament bulbs come with a full size glass globe, and may be tinted yellow.

RE: Signal lights R100 RS

Mike Buhler — Thu, 29 Oct 2026 12:04:43 +0000

Running all standard bulbs, I'll compare the rears I just put in to the front ones to see if they're different.

RE: Signal lights R100 RS

Rick Schroeder — Wed, 28 Oct 2026 20:11:49 +0000

MIKE, I noticed in an earlier post that you asked about changing to LED lighting for your directionals. If you mux incandescent bulbs with an LED in the same circuit, you'll get strange flash patterns. Make sure all the bulbs are the same type in both the front and rear directionals. Then make sure you have a LED flasher as Richard mentioned in his response. Sounds simple but it makes for some head scratching. Good luck

RE: Signal lights R100 RS

Richard W — Wed, 28 Oct 2026 13:22:26 +0000

• You have most likely substituted bulbs of the wrong internal resistance or voltage. There are numerous 12V bulbs with a single filament, but only 1 bulb number will function properly as a Turn Signal. This is because the actual flasher module uses a "bi-metal component" that is counting on a very specific current. As electrical power flows through the bi-metal arm it heats up. As the arm heats up, it starts to bend and flex away from making electrical contact. And just like a manual switch, when the electrical contact is broken the light goes OFF. The bi-metal arm (now with no electrical current flowing) starts to cool, and so it bends back to its original position, once again making contact, and the process starts all over. (Watch this YT video: https://www.youtube.com/watch?v=f17dXzrpl90 at about 4:00 to see this in action.) Those very specific bulbs are what determines the very specific current flow to trigger the bi-metal flasher operation.

• If the bulbs are lighting up at all, then you have some type of "ground" return. Inside the tail lamp housing there are 3 Brown return wires that mate with the harness (L turn signal, R turn signal and the TL itself). Unplug those Brown wires and treat the male ends with a compound that fights corrosion, such as No-Ox-Id by Sanchem.

• Turn signals don't stay ON long enough, to get hot enough, to chase out the humidity. What I find very often is that the 50 year-old socket for the bulb (the steel part that contacts the brass "base") has some rust on it. That rust may be adding electrical resistance to the flasher circuit. These rusty sockets can be treated with, you guessed it, No-Ox-Id by Sanchem.

Hope this helps.

RE: Bing 64/32/13&14 carb syncing process

Tim Cubbedge — Wed, 28 Oct 2026 13:08:06 +0000

I have a Harmonizer for sale. They really do make this job much easier.

Thanks but think I nailed it.

RE: Signal lights R100 RS

James Strickland — Wed, 28 Oct 2026 13:04:57 +0000

If you replaced original incandescent bulbs with L.E.D. bulbs, It could be that the impedance is insufficient to cause the flasher relay to cycle on and off as designed. Generally speaking, a quick flash indicates a failed bulb or other disruption of continuity. An easy test for that would be to put the original bulbs back in and see if the issue resolves itself. Turn signal bulbs ground thru the socket sleeves. To confirm the ground path of the turn signal sockets, use a volt/ohm meter set to ohms and touch one of the leads to the socket sleeve and the other end to the negative battery post. A disrupted ground path would read as open or display no numeric value. If you have pulled the negative battery cable, test to the transmission case where the battery cable fits up.

Signal lights R100 RS

Mike Buhler — Wed, 28 Oct 2026 12:21:57 +0000

Me being an electrical idiot I don't know much about it. I replaced my rear signal bulbs and now the right side is steady on and the left side is fast flashing limp mode. Can someone please tell me the fix for this? I had a suggestion of ground but what do I know?

RE: '89 R100RT problem

David Elkow — Mon, 26 Oct 2026 05:25:03 +0000

Glad you have your RT going again! Hope you find the issue with old carburetors.

RE: '89 R100RT problem

Richard W — Sun, 25 Oct 2026 16:56:32 +0000

Richard W, David, Thanks to the help I got here, yes it is sorted!

That's great news ! Ride safely, my friend.

RE: '89 R100RT problem

David Elkow — Sun, 25 Oct 2026 15:34:37 +0000

A humbling experience - I chased a subtle carb issue on my ‘78 quite literally for a couple years. Sometimes i could feel it, most times not. It felt like one side would run lean when cruising at steady throttle. Just a funny little slight hesitation. Of course, i had rebuilt the carbs. I would work on it intermittently, then put up with it. I double, triple checked everything. Replaced everything. Played with various needle jets and needle settings. It was crazy. Then one day i was reading some carb material on Snowbum’s site, and it sparked a new thought. I dug back in. And i found the problem. There was a sharp edge at the top of the steel center post on one of my carb pistons. See picture. With a little lateral force, that piston would catch or “snag” in the bore in the carb top. It was slight, but it was there. I dressed the top of the post so it would slide smoothly and EUREKA!, my troubles were gone.

so, my theory is, when i had the carbs apart they were on a bench at a school i worked at in maintenance. I believe that someone, probably a student in shop class, knocked or dropped that piston on the floor. Of course, they put it back and said nothing. Years later, i finally found it.

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