Thirty five years of happy wrenching and riding.

I became the custodian of my 1975 BMW R90/6 ‘airhead’ motorcycle 35 years ago today, buying it for $2,000 in Los Angeles from the original owner with just 15,000 miles on the odometer. René, the wonderful Chilean seller, was returning to the country of his birth and assured me that riding a single track vehicle on local roads was not a prescription for a long life. He also informed me that he had turned down two earlier offers from ‘irresponsible kids’ who would not accord his machine the duty of care it was due. I do not think I have let him down.

This beautifully made machine, an exemplar of the best mid-twentieth century technology – and not all that much changed from the 1931 original design – is notable for its near total absence of electronic gizmos, a source of considerable joy for this mechanical engineer. Any self respecting mech eng will tell you that electricity is the work of the devil. And this is very much an engineer’s dream for the machine is easy to work on, most parts easily accessible with few special tools required. Best of all the machine’s enthusiastic following sees to it that most replacement parts remain available, 30 years after the last airhead left the German assembly line. Yes, there’s more maintenance than with a Honda but reliability is comparable to that of those fabulous Japanese designs.

What follows is a pictorial history of my time with the bike over the past 35 years. I continue to ride it regularly.

June 16, 1990. Accepting delivery in Encino, CA from
the first owner, René Francisco Lama.

At the fabled Rock Store in Malibu in 1990.

Ready for touring with bags and a small windshield.
The original café fairing broke when the bike fell over
in my Encino garage during the Northridge earthquake,
January 17, 1994, the only time it has been down.

Manufactured in October 1974, the bike was sold by
Bob Brown’s Motorworks in Pomona to the first owner in 1975.

The motor is a simple two valve pushrod design.

Engine maintenance is easy owing to the horizontally
mounted ‘boxer’ cylinders. The valve cover and valve
head have been removed here.

Resealing the cylinder with new gaskets is a simple task.

With the piston removed the con rod is held safely
in place with a cable tie. Nicks on the base gasket mounting
surface are not a good idea. The rubber pushrod seals
are replaced at the same time – they harden with
age and heat and leak.

Spaghetti junction. Not BMW’s proudest moment.
The wiring meets up with a small distribution board
in the head shell

The stock Bosch starter motor is awful, struggling to
turn a cold engine. After having it rebuilt twice over
the years I replaced it with a Toyota truck starter with
an adapted Bendix. Twice the power, half the weight and
current draw. The bike’s modular design means that the
starter can be removed in under 15 minutes.

Look hard enough and you can still find original German
Bosch copper spark plugs. That’s all the bike needs in
the ignition department. And ignition timing is 100%
mechanical, no electronics.

A collection of metric fasteners is essential.

Back in the day batteries came filled with liquid acid, which
would inevitably leak, corroding the battery tray.
The tray has been removed, wire brushed and repainted here.
Modern gel cell batteries do not leak, so this is a lifetime fix.

Well, I do have one electronic part in the bike. Here’s
the daylight sensor for the Kisan headlight modulator which
flashes the headlight in daytime riding, enhancing the rider’s
visibility to motorists focused on their cell phones. The
three position steering damper is below.

Over the years I have replaced most of the steel fasteners
with stainless ones.

A rare failure – the choke cable toothed follower snapped
rendering the choke inoperative on one side. A fellow airhead
kindly gave me the replacement part which is NLA from BMW.
Magura could learn from Rolex when it comes to engraving.

The bike came with the smaller 18 liter tank,
beautifully pinstriped by the ladies in Berlin.
The QD trunk is by Givi of Italy, and holds a full face helmet.

A few years ago I finally got my beaten up 22 liter larger
tank refurbished and the pin striping, done in
Scottsdale, is beyond perfect. I think it
looks far better than the small tank.

Way ahead of its time, the largely modular design makes
accessing most assemblies easy. Here the rear wheel,
driven by a shaft – no chains here – has been removed
for tire replacement. Sadly the wheels require
tubed tires, far less safe than modern tubeless ones.
The shocks are aftermarket Konis, superior to
the stock ones, and recently rebuilt.

The brake light sensor is a simple pressure switch.
Here I am replacing it as it failed after 30 years.

During baking Scottsdale summers I kept the bike indoors
to avoid premature rotting of rubber parts. Eventually
I insulated and air conditioned the garage to make for
better summer storage.

After 30 years the saddle foam was shot and the vinyl
seat cover was cracking. New foam from the Fatherland
on the left.

New seat cover installed over new foam
A very time consuming job, but very satisfying, and
easier on the bottom to boot!

While the stock tool kit is excellent the pliers
are poor quality. A superb pair of Knipex adjustable
pliers does the trick far better. The cylinder on
a chain emulates TDC when adjusting the mechanical points
ignition when installed on the nose of the cam.

The twin FIAMM Italian horns are not only much louder
than the weak stock offering, they are also paired out of
tune, the resulting interference effect on the two sound waves
making the output truly obnoxious. You want that in
a world which often does not see or hear bikers,
especially those on quiet BMW airheads. As the horns
draw high current I added a relay to avoid frying
the relatively lightweight horn button circuitry.

The horizontally opposed boxer engine design lasted through
1995, but remains available in some of BMW’s latest
machines where it is now oil and air cooled. Here the
1975 valve cover compares with that on a 1994 R100RT
touring machine. No prizes for guessing which I prefer.

In Scottsdale, Arizona.

A happy owner, with the bike on an all American
Handy bike lift. The hair is greyer but the smile is
every bit as wide.

I wish I could tell you that I am looking forward to the next 35 years with this beautiful machine but statistics and anno domini suggest otherwise.

A spot of wrenching.

One of the greatest joys of acquiring a new vehicle is the that of fixing the many things that need fixing. ‘New’ as in ‘new to me’ as I never buy new. I prefer to let someone else pay the 50-75% depreciation.

So when the Honda Silverwing maxi-scooter joined the stable recently, for the stunning sum of $3,250 with just 13,500 miles on the odometer, the first acquisition was the Factory Shop Manual, and I don’t mean some useless PDF version. Only paper manuals cut it for the serious mechanic and I was lucky to track down one of the few new ones left, the scooter last being imported to the US in 2013.

The Factory Shop Manual.

Hundreds of pages thick, the manual testifies to the complexity of a fuel injected, electronic ignition motor with linked ABS brakes and an automatic transmission. Mercifully the scooter is made in Japan, not Germany, with all that implies for the best design and quality control on the planet.

The only issue with this manual is with the circuit diagrams. While I have long known that electricity is the work of the devil, I also believe in ‘better the devil you know’, and that means having something I can read when messing with the circuitry. And the small print of the circuit diagram in the manual means it’s not useable.

However, it was a moment’s work to cut out the page from the manual, scan it and print it with SplitPrint which makes child’s play of printing something small over as many pages as you need – six in my case:

Making things readable with SplitPrint.

I needed a decipherable circuit diagram to permit installation of the greatest single motorcycle safety device on the planet – a headlight modulator. I have run one on my 1975 BMW Airhead for over two decades now and there is no better weapon to make SUV driving Psycho Mommy, with Little Johnny being rushed to his fifth activity of the day, sit up and take notice while fixing her hair and gossiping on the cell phone. Kisan tech has looked after me all these years and the device is 50 state legal. I keep a copy of the law in the glove compartment in case Officer Plod is on a sugar high from his third doughnut of the day and has forgotten the basics of the law.

The headlight modulator.

The device is inserted between the high beam bulb and its base. A separate daylight sensor is installed to ensure no modulation occurs at night, in compliance with the law. The flashing headlight may be a nuisance to car drivers, but being seen beats being dead.

However, the opening for headlight replacement is designed strictly for ultra petite Asian hands so the whole front fairing had to come off to grant access:

36 fasteners removed, and access to the bulbs is easy …..

Interposing the Kisan modulator in the headlight circuit is trivial. What actually dictated the need for the readable wiring diagram was the wiring in of a USB socket/voltmeter into the left glove compartment to provide power for an iPhone. I tapped into the circuit of the low beam bulb which is always on, switched with the ignition key. Here is the dual USB socket/voltmeter, neatly installed:

USB power for an iPhone.

The next task was to change the engine oil and filter (replacing the chintzy aftermarket one with OEM), the coolant (the scoot is liquid cooled), the brake fluid in both brake circuits and the all important drive belt:

Maintenance tasks.

The Silverwing uses a gearless Continuously Variable Transmission with a Kevlar drive belt riding on two pairs of conical pulleys. As the throttle is worked these expand or contract, changing the gear ratio between the motor and the rear wheel, a system invented in the 1960s by the Dutch for their Daffodil cars. Had they named these the Tiger or Lion they may have sold in the US. In the event, ‘daffodil’ was just too effete for the tattooed crowd. Honda made hay where the Dutch made failure. The belt has a life of 16,000 miles and while mine came with 14,000 on it, it was also 14 years old so common sense dictated replacement – see the lower right image above. It’s made by Mitsuboshi in Japan, Mitsubishi’s long lost brother with a spelling problem. It’s actually a very easy job, made easier with the use of an air wrench to remove that stubborn front pulley retaining nut. And while the belt is off, the rear drive oil is easily replaced along with the sponge final drive filter – both oft neglected tasks.

Tires were next. That small contact patch on a two wheeler is vital to safety and the date codes on the Bridgestone tires disclosed them to be eight years old, even though only 60% worn. I like to remove my wheels and take them to the tire place not so much for reasons of frugality but because I do not trust a guy who works on agricultural Harleys to have either the expertise or caring to do the job right on a sophisticated machine.

New front and rear OEM Bridgestones installed.
Serious rubber for an innocuous looking scooter.

Rear tire replacement is labor intensive, as a disk brake is used. This means the exhaust, rear brake caliper, parking brake caliper (yes, there’s a parking brake!) and swingarm all have to come off before the wheel can be pulled off. And when it came to removing the swingarm, corrosion had done its thing and the use of a three legged puller, straight out of the Spanish Inquisition, was called for:

Extricating the swingarm. Note the two brake calipers at left and right.

It’s always something with old machines. Fortunately removal of the front wheel is easy, requiring removal of the axle – one nut – after freeing up the two pinch bolts.

Replacement of the air filter was next and boy, was the sake ever flowing when Honda’s design engineers came up with this design. It takes me 15 seconds to remove, clean and reinstall the air filter in the clothes dryer. The same task on the Silverwing takes an hour after you have removed the rear yoke (4 bolts), the rear decorative plate (2 screws), the right footpeg (2 bolts), and the right body panel (2 screws). Then you have this:

Not Honda’s proudest design moment.

Yup. Count ’em. One dozen screws to remove the cover.

Then one more screw and the filter is replaced:

22 fasteners later and the air filter is disclosed.

With USB power to hand for the iPhone, it was next necessary to craft a centrally mounted iPhone mount. Side mounted handlebar mounts do not cut it, so I procured a RAM mount and mounting ball, replacing the handlebar cover retaining bolts with a home made plate to mount ball and mount on:

RAM mounts have a great reputation and there is no way the iPhone is going to fall out. The red arrow denotes the sprung upper retainer, the green the fixed side motion limiters. This is the ‘large’ RAM mounting plate and easily accommodates my iPhone 12 Pro Max, even with a metal protective ‘bumper’ installed.

The RAM ball mount is attached to a home made plate at left.

That plate is mounted on neoprene bumpers, heeding Apple’s recent warning about excessive vibration destroying iPhone cameras, though I do believe their message was aimed at pigs on Harleys. The counterbalanced, parallel twin in the Silverwing is the smoothest motorcycle I have yet ridden.

Ergonomics came next, the Silverwing’s low 29.1″ seat height meaning that my feet were far too high, causing back pain. As the floorboard height on a scooter is not adjustable this means that the seat had to be raised, which was accomplished with a water inflatable seat pad with a foam garage kneeler below, for a rise of some 3.5″. Now I could look over the tall windshield and the back pain was gone:

Seat modifications.

On cold days I ride with a heated vest, a lifesaver which requires a high current connection to the bike’s battery. If your kidneys are warm the rest of your torso will follow. There is no battery power take off on the Silverwing but after rooting about in the lower left of the bike I found a handy unused flange with two tailor made bolt holes. It was a matter of moments to craft an aluminum plate to attach to these, with a large hole at the other end for the robust Hella socket, wired directly to the adjacent battery:

The home made plate holding the Hella socket – without and with bodywork attached.

Now the heated jacket can be plugged in to the conveniently located, unswitched socket behind the rider’s left leg.

Body damage? There were a couple of spots where the paint had been scratched, easily remedied with matching touch-up paint from Colorite. The lower left skirt was badly scratched and cracked in one place:

Damaged lower left skirt.

Outlay of the modest sum of $50 saw a new replacement; I have never found repairs to cracked plastic to last in the hostile setting of a motorcycle. Total overhaul costs – new tires, new drive belt and the body panel – ran under $600.

One final touch was called for, a riser for the seat back rest to position it strategically. Here is the result:

The back rest riser installed.

She’s now ready to ride!

Maxi-scooter.

Americans do not ‘get’ scooters. Neither do Canadians, but that lot pretty much ‘gets’ nothing in any case. Still, we can excuse our northerly friends on grounds of climate, as theirs is awful.

After decades of motorcycling I bought my first scooter, a Honda PCX150, four years ago. It has proved to be the perfect urban errand machine, faster to 45mph than anything absent a Porsche Turbo or a Tesla and, with an added top box, it came with abundant storage for groceries and what have you. Averaging 95mpg on regular gas, and taking no space to park, what’s not to like?

Indeed, think about this. Were the 40% of the United Sates, bathed perpetually in sunshine, to adopt scooters as its primary transportation, rather than opting for the single driver in an eight seat SUV behemoth, Middle East and Russkie hegemony over global energy supplies would disappear immediately, and both evil empire petrostates would collapse overnight, Novochok or no. Putie, the world’s wealthiest person, would have to buy Switzerland and hide out there with his stolen billions. Simultaneously, America’s wasteful military spending would halve and we might even erase poverty in our homeland. Ah! well, one can but dream.

The Honda Silverwing, alongside an old friend, my 1975 BMW R90/6.

But Honda, maker of the world’s finest powered two wheel vehicles, is not a quitter. Back in the 1980s they tried to make motorcycling a more automotive experience, with the machine’s works shrouded in plastic to hide the nasty bits. They called it the Pacific Coast. It came with an excellent 800cc V twin with hydraulic valves (no adjustments needed!) and abundant power, great under seat storage and it was …. a complete flop. Honda imported it during 1989-98 until they finally gave up. Great machine, but spares are increasingly hard to get so not a viable modern ‘super scooter’.

Honda’s magnificent Pacific Coast. Vast underseat storage.

But not being quitters, Honda had another go in 2002. For years the big touring motorcycle of choice has been the Honda Gold Wing, now morphed into a six cylinder 840 lb. behemoth with a reverse gear to convey Americans’ waistlines out of tricky parking spots and, for all I know, a refrigerator and four channel sound. All for the price of a nice new car. An obscenity among motorcycles, it continues to sell well for chunky riders giving up their 3 tons SUV for a spot of light weight, relatively speaking. Ah!, the open road. So, deciding on a sane alternative, Honda decided to make a lightweight Gold Wing and came up with the idea of the maxi-scooter. A traditional scooter but with a fuel injected 600cc twin for power and genuine 100mph capability. They imported the resulting Silverwing to the States from 2002 through 2013 and it was …. a complete flop. Americans not ‘getting’ small 150cc runabouts, which is what scooters were traditionally, what hope was there for a midweight genuine tourer with all the scooter’s cargo carrying verve and true motorcycle performance to boot?

Yet that is exactly what the Silverwing is, with high global sales (Asians and Europeans truly ‘get’ scoots, foul weather notwithstanding) so parts availability is not an issue. The US import’s design changed very little with optional ABS becoming standard in 2007, along with a 10% increase in fuel economy, meaning an average of some 55mpg on, you got it, regular unleaded. Mine, acquired after a long search, is a 2007 with ABS and came to me for pennies on the dollar with just 13,800 miles on the odometer. A couple of small boo-boos in the paintwork from a parking lot tipover by the seller are easily touched up and while new tires and a transmission drive belt are dictated largely owing to aged rubber, the machine is ready to ride as purchased. And that drive belt, which takes all of 30 minutes to change, is part of a Continually Variable Transmission whose provenance dates to Holland and DAF’s Variomatic of the 1950s, plonked into their Daffodil sedan. Yes, you guessed it. With a name like’Daffodil’ the DAF’s chances of success in a market dominated by Rams, Chargers and Mustangs were zero, so the DAF disappeared from these shores but left behind an innovative dual pulley transmission design. And Honda was paying attention. Honda perfected it, so much so that their CVT is to be found in a high proportion of the world’s scooters, none of which has so much as a clutch or gearshift lever in sight. The Silverwing’s CVT belt has a 16,000 mile service life and even your better half could change it with a minimum of tools. Thirty minutes for me using one of these, two hours and a bad back for those without.

After the usual check of vital signs – tires, oil, coolant (the engine is liquid cooled), indicators, brakes, etc. – I removed the ‘duck tail’, drilled it in the spots indicated by the factory, and fitted my small Givi top box.

With the QD top box in place, you have all the storage needed.

A quick 50 mile shakedown run disclosed an engine which is most refined, along with disc brakes at both ends which stop the powerful machine fast. At 541 lbs fuelled, the Silverwing is some 50 lbs heavier than my old BMW airhead, but that weight penalty brings with it fuel injection (no choke needed), ABS, a powerful parallel DOHC twin and abundant protection from the elements. The ride is the quietest I have experienced on two wheels and Honda has paid careful attention to eliminating the irritating vibration which bedevils parallel twins. Have you ridden a British bike recently? They have added vibration counterbalancers to the motor and the absence of handlebar buzz is similar to that in my 1975 BMW boxer twin. Ah!, progress.

What’s left to do before some serious long distance touring? Well, the aforementioned new rubber – tires and transmission belt – but, most importantly, I have ordered a headlight modulator, as used for decades on my BMW, to grab the attention of soccer mommies rushing junior to his fifth sports activity of the day in their behemoth SUVs, the while drifting into the opposite traffic lane while texting on their cell. Once fitted, I will feel much safer. There is no better attention grabber for a two wheeled vehicle.

The maxi-scooter is recommended to anyone who ‘gets’ it. Just be sure to practice on something less powerful first, if you are new to motorcycling. So is the old airhead for sale? Heck, no. I need something to work on during the summer months in the furnace that is Scottsdale.