Airhead Cleanup

Oh No! Another bike tear down. My landlords must just love me.

Task at hand today is just to clean everything off somewhat, check the wiring and cables and inspect for any other unknown issues to get a better idea of what work lies ahead and what I’ve gotten myself into.

First things first, new tire! I’d ridden back and forth to work a few times and just joyriding around close to home I must have put 2-300 miles on the old cracking and dangerous looking Dunlops that were on there. It’s now got Metzeler Lazertechs on the rear that the local BMW guru recommended for old airheads. I’ve left the front Dunlops on there with the cool raised white lettering as they still have a lot of life in them and arent that old. So now the bike mismatched Metzelers on the back and Dunlops on the front just like my Yamaha.

I’ve also gone by Batteries Plus and gotten a new sealed AGM sportbike battery. I wouldnt expect that a store that only deals with batteries would get a lot of business but the phone was ringing off the hook and they said business has been very good. The guys there were very knowledgeable. I said what I was looking for and they lead me to a very small batter that only had 120 CCA and I didn’t think that would work. So I pulled the seat and looked everywhere for a number on the old one and only came up with Napa 14-A2. Off the top of his head the guy says oh thats a wet battery of this type and size and showed me motorcycle replacements of the same specs, not a lawn tractor kind. Very helpful, I’d highly recommend them for any unknown battery stuff.

The wet battery that was in there already left me stranded twice when running out of a charge. If I needed a new battery I decided to spring for the expensive sealed kind so I could eventually mount it on its side in the tail section if I Cafe the bike down the road, and no maintenance is a big plus in my book. With the new battery the bike starts better, idles better, runs stronger, and sounds better too. It made a huge difference.

I scrubbed down the engine block with some Simple Green and some scotchbrite pads. It takes quite a bit of elbow grease but eventually it looks a lot better. I wasn’t expecting to go through the scrub pads so quickly, I need to get an industrial sized box of them I guess.

Heres a good before and after shot of progress on the fins. How I did this was fold a pad in half and just work it down in there back and forth, they clean up pretty quickly this way. Upon closer inspection the block still doesn’t look 100% clean in this pic but believe me its way better than it was.

Freshly brightened right side of engine.

On one half of the airbox cover I experimented with some aluminum polish. Cleaned the piece off first with simple green as best I could and used a buffing cloth to polish it. Using a cloth doesnt work so well, it only ends up shining up the high surfaces which makes the lower areas just look worse. New Method: apply polish with one of the scotchbright pads. Using the scrub pad gets the polish down into the crevices and cleans it all evenly. Buff off with the cloth and you’re left with a nice and not too shiny uniform surface.

Looks pretty darn good to me. I don’t want the thing to look too shiny, then it’ll just be more work to keep it looking clean. I now need to do the same to the rest of the block. This process is fairly labor intensive and time consuming, this is about 45 mins of work on this small piece. One drawback, that Blue Magic Metal Polish is freaking expensive, it was $14 for a little can of it. It may take more than a can to do a whole engine.

I will say one thing, that metal polish is amazingly good stuff. It made short work of shining up my weathered front rim and shining the chrome fender stay. I had been wanting to powdercoat the rims black and put on new chromed spokes on both wheels but after seeing it like this I may just leave it shiny. The spokes still have a lot of surface rust, I’m not going to bother with those for now.

After what a good job it did on the wheels I decided to try it on my Supertrapps. The pipes were a brushed stainless steel with the grain going around the pipes. They were yellowed and discolored unevenly with blotches here and there and just looked old and tired. The grain made polishing them a bit of work as I had to twist the cloth around the pipes and try to keep an even shinyness down the length of them. Only 5 mins of work and one side looked like new. Amazing!

With the tank off I started cleaning up all electrical connections I could find. Pull the wires off and spray some contact cleaner on both and reassemble. I need to get some dielectric grease to ensure they don’t corrode again and get a better connection.

These brown ground wires were not screwed in all the way. No idea what they go to but I fixed them anyway.

No idea what all of this mess does either but I tried to only do two wires at a time so I wouldn’t get them mixed up. I hope they all went back correctly, it still runs so I guess I didn’t screw up yet.

Extra wire? What the heck does this go to? Theres several tabs nearby that this might fit on but that would leave one coil without a wire in the same place on the other side so maybe it doesnt go to anything. Too hard to trace it back through the wiring harness just yet.

Another pair of extra wires. These look like they were added by a previous owner to run some after market gadget. One wire goes straight to the battery, the other goes to the ground by the coils seen above. No clue what may have gone here either but I’ll keep them there for now incase I think of something to add later, like say a voltage meeter.

Found yet another pair of extra wires under the tank stashed away, but these look like OEM wires and I’m guessing they went to this master cylinder cap. It looks like it has a float switch in it to warn you that you leaked out all the fluid and have no front brakes, theres a brake failure light on the dash. How nice of BMW to think of this for us, so they aren’t completely compromising safety for looks with the clean handlebars. I think with a bit of stained glass flux and solder I can put new tabs on here and fix this.

Once upon a time it appears there was a master cylinder leak too. Fixing the sensor is probably a good idea. Hopefully stuff inside the front cover isn’t a nasty mess because of this like I’d seen on other BMW airhead rebuild threads on ADVrider.

Frame definitely needs some attention and repainting or powdercoating but luckily theres NO rust anywhere that I can find except for this little bit of surface rust under the master cylinder. I think I really dodged a bullet and lucked out on that. I’ve gotten a nice solid candidate for a rebuild.

Left side of the engine before cleanup.