$190 Gas Springs and a plethora of fairings…

Of course, I can’t simply rebuild a bike “as is”. I am not one of the many folks who seem to take on the role of voluntary BMW docent, and I don’t think “original” or “as built” holds much appeal on its own. Don’t get me wrong, sometimes an all original survivor or restoration is a wonderful thing and I am glad that folks are into that. For me, I don’t think I will ever do a “concours” or pure original restoration. (As I write this, I am eyeing the barn-find R90S in the garage). For Blue, I am aiming to create a great airhead for actual touring. That’s going to mean making some accommodations for modernity, performance, capability, etc. Where I can, I will use BMW OE or reproduction components, but not at the expense of my goal.

Because I want to use this as an actual touring bike, I am unsatisfied with the single headlamp configuration. The headlamp, itself, is just OK. Not great. I may consider something more radical there before I am done. Even with an LED conversion, I want to add more upfront lighting. Something that I loved about my road trip on a rented R18 was the auxiliary lights. They made all the difference feeling confident driving across the desert.

After spending way too much time looking into modern options, I just can’t abide using any of the standard LED auxiliary lights sold by aftermarket manufacturers. They all seem to be made specifically for the contemporary adventure rider crowd and have a sci-fi/batmobile/pseudo-military gear vibe. /to me, that is just silly on an airhead RT. I considered buying the auxiliary light kit for an R18, but they are extremely costly. Digging into BMW OE options, I found the answer in the European parts catalog.

All BMW airhead RTs have fairings that are ready to have OE authority lights bolted in. These rarely made it to the US and are pretty hard to find. When installed they replace the air inlets with flip-out auxiliary lights. These are lever actuated and install adjacent to the RT storage bins. That weird little blank held in with two Philips screws? That’s where the levers go.

Back in January, I was able to find a beat up RT fairing with these installed.

Over the past few days, I got around to getting all my body parts ready for paint, and these needed to be included. That meant delving into a bit of airhead disassembly that is not well covered. Most folks simply want to remove the RT fairing or replace it (like I did with project Red). As I am hoping to get this all put back together, I needed to pay more attention to the assembly. I started with the fairing from Red, since it’s not likely to be reused at all. Once I was sure of what I needed to do, I removed all the parts from Blue’s fairing and boxed them up.

Then I got at the white fairing with the lights. These create some differences with the addition of the levers, necessary wiring, and the blanks covering the vents.

Getting the parts out is a bit tricky, mainly due to the wiring. Harnesses are fished into place before the components are installed and this constrains the movement available during disassembly. It’s more tedious than troublesome. Once inside, you get to see the lighting assembly completely. The standard brackets holding the pocket/vent panel is replaced with a more robust version accommodating the lever. There is also a second hinge assembly that is the mount point for the light pods. A linkage arm is used between the brackets and there is a gas spring that is intended to assist the extension of the lights. It’s a clever and slightly complicated design that won’t throw any BMW owners off.

Once all the bits are removed, we can see what we have.

• 2 Lever bracket
• 2 Light-pod hinges
• 2 Light elements
• 2 Gas Spings
• 2 Linkage arms

This fairing had a mix of very good and very bad hardware. The brackets, hinges, and mounting bolts were all in excellent condition. Not so much for one of the linkage arms and both of the gas springs were shot. My mangled linkage arm was bent quite a bit. I have no idea how this would have happened but even if it were clean, it would be unusable. Less surprising, the 50 year old gas springs had lost all their contents. This is all a good news / bad news situation. On the good news side, the gas springs seem to be available for order. The bad news is they are about $190 each. As for the linkage arms, forget it. Unless you have another one of these assemblies laying around, you’re out of luck.

I could not bear to spend $380 plus shipping on new gas struts. Especially since I have no idea when the replacements were manufactured and how well they hold up over time. Looking at them they were made by Lift-O-Mat in West Germany.

Researching these turned up almost nothing. Lift-0-Mat is not a product line from Stabilis and they no longer make anything quite like these. Nothing available on the part number painted on the body and no historians discussing how to decode the numbers. All I can gather from the markings is it appears to be a 200 Newton force spring. That’s about 50 pound feet. So I was off to see what other suppliers can offer. I was able to find an option that closely matched the size and force, but the modern spring uses a smaller rod and eyelets. What’s more, it’s threaded at M3.5. That’s a problem, since I can find eyelets in M3 or M5. There does not seem to be a sleeve style reducer from M3.5 to M5, so I am out of luck. this leaves two options.

• Drill out the supplied eyelets
• Have my own manufactured

The manufacturing route would be my preference BUT, PCBWay now charges the Tariffs, so that’s not economical and don’t bother looking for a US based shop. I have estimates ranging from $400 to $750 for a single eyelet. Seriously. These are small, aluminum parts that would take about an hour to program, produce, and inspect. As an aside, this is yet another tick mark in the “Just buy a mill and lathe” column. Oh well. I opted to drill them out and see where it left me.

They are thinner than I would like, but since they are springs that push outwards, Most of the eye is just to hold them in place. There is plenty of material towards the center, where all the force is applied. I’ll see how they hold up for now.

For the linkage arms, there is no choice but to make my own. For this, I needed a left hand thread cutting die since the linkage arms had left and right threads. This allows you to spin the linkage arm and adjust the overall length, and hence the final open and closed position of the light pod.

I got everything I needed from McMaster-Carr. Some 5mm 7075 aluminum rod, M5 LH and RH rod ends, and the two thread cutting dies I would need. I cut the rod to length, ground a chamfer on the ends, then used my drill press and a vice to hold everything while I cut the threads by hand. I did not get a photo of my setup for this, but I put the rod into the chuck and the die in the vice. Some careful alignment of the vice before bolting it down made a mostly repeatable setup. I could use the arbor to apply force with one hand while spinning the chuck with the other to cut the threads. These are the same length as the good original, but I may need to make new ones if I need more adjustability. Still to do is grinding/filing a flat on the rods so I can use a set screw and 3D printed knob to make adjustments when installed. That will wait, since my 3D printer gave up the ghost after 8 years. A new one is on the way though.