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| Map of Travels |
| A Quick Little Machine The Honda S90 Transformed Part One Honda’s S90 motorbike, manufactured back in the sixties was a wonderful little machine, that in my view, deserved better. It was an easy bike to work on with just one jug, one spark plug and one carburetor that pushed the bike to almost sixty mph. Not bad for a 90cc single and eight tiny ponies right out of the box. When I was done a little more than a year later the bike reached seventy-five mph and boasted more than eleven horsepower. For its size it was quick. I bought the S90 because of its diminutive size. I was into small at the time, partially because it was a simple machine to “wrench” and because it fit my limited pocket book. After attending the Tourist Trophy (TT) race week at the Isle of Man and watching Honda’s little 50cc racers buzz around the course, I was hooked. I couldn’t afford a 50cc racing replica or even if I was fortunate to own one, wouldn’t be able to operate on the road. So I did the next best thing and bought the S90. It was a step up from the step-thru 50cc town bike. The S90 was a true road bike with 40 more cc’s. Honda gave it a motorcycle look but it had no panache. The pressed steel frame was a half step up from the step-thru model. No doubt cost was a factor and I should be grateful for that. I figured it would be the perfect size for a “shade tree” project done in a corner of my basement. For once in my life I didn’t rush pell mell into the project but spent almost two months asking questions and taking notes. I was faced with a number of choices. Should I use mild or high carbon steel? Thin or thick wall tubing? Electric arc or gas? Did I know how to weld with electric arc or gas? No. Did I have any idea how to braze? No. Why did I think I could complete such a difficult project. As it turned out, I had to build more than one frame. A big plus was that no one told me I couldn’t. I’m handy with tools so I wasn’t frightened or discouraged by the difficulty of the project. I just dove in. First thing was to disassemble the bike. Every last nut and bolt. There were parts laying everywhere. Finally all that was left was the frame, and from that I cut off the head tube and engine support brackets. I was going to use the brackets as a pattern then decided to use them instead. I tried a small arc welder, on low power setting, to practice on mild steel tubing I’d decided to use. It was a disaster. I did nothing but burn the tubing. They say practice makes perfect but I was sure I’d age appreciably before I mastered the technique, so I tried welding with gas and had the same results. I was becoming a bit discouraged until I talked to a few welders and they pointed out that for someone of limited knowledge and skill, brazing would work. So I bought a small gas outfit and within a short time was gluing tubes together with bronze welding rod. I used an 11/12” diameter top tube as the spine of my frame and from that hung various smaller diameter tubes for engine, seat, and linkage support. When it came to angling the head tube for proper trail I also had to make sure the front and rear wheel were in alignment. I hung a carpenters string and plum bob from an overhead nail to align the head tube vertically and horizontally I remember several weeks went by as I frequently visited the workplace to eyeball the string and see how close to vertical the head tube was positioned. I looked at that string till I was crossed-eyed. It had to follow the centerline of the head tube. During those several weeks I constantly tinkered with the tube, held in place with duct tape. I fashioned battery brackets, brake and shift levers and linkages. I drilled holes in every piece to lighten the bike. I was able to salvage the side stand but not the center stand and kick starter. It became a run and bump machine. The project finally came together more than six months later. The engine was still stock. I used the S90’s fuel tank, wheels, seat, headlight nacelle and brake light. I worked many hours to make sure the welds were clean and strong and that everything worked. I remember pushing it up the ramp one morning into the back yard. I walked the bike to the street, turned on the ignition, sprinted ahead ten steps and the launched my right hip onto the saddle as I popped the clutch. I shifted into second gear and off we went up the hill. A few minutes later I was back and not a happy camper. The bike shook her tail as we rounded corners. I thought for a moment the bike was hinged in the middle. Not good I thought as I coasted down the hill. I was disappointed big time but had no thought of throwing in the towel. A month later, after massaging my ego, I was ready to unglue all the bits and pieces and begin again. Part Two The problem was the outer dimension of the tubing and thickness of the wall. I was disappointed with my first attempt but not surprised. So after unbrazing the engine support mounting and head tube from the smaller tubes I was ready to begin again. The top tube, running horizontally from the head tube to the end of the seat, is the backbone and from it all the loads, static and dynamic, are carried. So it’ s pretty important to get it right. I increased the diameter, from inch and a half, to two inches and increased the wall thickness by several thousands. In fact even the down tubes used as engine and seat supports where several thousands thicker as well. Using the same measurements I cut and brazed, completing the frame in several weeks. The last component was the head tube so I used the same technique and strung plumb bobs. As with the first frame I was in no hurry to even tack the head tube to the frame. Patience can be its own reward especially when things go our way. The head tube was finally tacked to the top tube. I removed the duck tape and checked the realignment again. I spot brazed the head tube in several places and checked for any warping. I took an overnight break and the next day completed the braze. I did it in small steps, giving it time to cool down before moving on, eliminating any tendency to twist. The rest of the frame tubes went together easily. All the tubes were notched, filed and sanded so they’d fit together with little or no gaps. The brake and gear levers were cut, trimmed, drilled and polished from ¼ inch aluminum sheet. The fuel tank and front brake drum were from Honda’s 160cc bike. The 160 brake drum was laced into the 90’s front wheel rim. Back wheel was left stock. Fenders and tank were refinished in silver with a red trim stripe by my friend Mad Tiny. After the tank supports, battery shelf and foot rests were glued on and the bike completely assembled I removed everything once more to have the frame nickel plated rather than chromed. I picked up the completed frame from the plating shop two weeks later. Ahhh, it was a beautiful thing to behold and when I slipped into bed next to my wife, Bea, that evening the frame was resting comfortably on the floor close at hand. I did take a huge ribbing from my bride on that account. During the weeks of construction I delivered the engine to Oscar Liebmann’s shop where the engine was over-bored to 105cc for a larger piston, a hotter cam installed and the timing altered. As the frame and parts came together the completed engine was installed as well. For the initial test run I stayed with the original carb. The frame performed beautifully. There was no sign of that awful hinge feeling in the middle. The bike was stable, accelerated faster, stopped much quicker with the larger front binder and looked smashing in her silver and red paint. As in the first incarnation I still didn’t have room for a kick starter. No problem. I though it looked cool to run and bump to fire up the ponies. I also played with fuel delivery, installing a Del Orto carb, but could never get the engine to idle, so I went back to the S90 unit. At a later time I was able to find, with some difficulty, a fairing that would fit. One afternoon I was running east down Route 208 in New Jersey, from Oakland to Fair lawn when a young man on a 350 Honda slowly passed. I yelled over how fast and he shouted 75. I was delighted preferring to believe his speed and not mine. GPS in later years, would have settled that difference big time. For a view of the bike before the fairing was added, go to my photos page. I equipped the bike with drop bars that didn’t bother my back or neck. I was thirty-eight at the time. Those bars would be impossible to use in my dotage. It was a wonderful, creative adventure. I had tremendous energy and passion in those days for trying new things and I guess I haven’t changed much as I’ve entered my senior years. The projects are a bit easier but no less interesting, and for that I’m thankful. |
| FOLLOW THE YELLOW LINE Motorcycle Touring with Stuart Davis and His Side Car www.followtheyellowline.com |
| Ramblings, etc. |