This build was featured on Town Moto. The post below is from the Town Moto blog:
Photos by Alex Lee
Our window bike for January is a heavily modified 1974 cb550 built by Kemp Archibald of Ripple Rock Racers. For an indepth look at what he did on this build keep reading below.
From Kemp: “The Roadster” build plan was to be true to the heart of the traditional café racer, a highly modified standard road bike that looks and performs like a road racer but is actually a daily ride.
For the build we chose a 1974 Honda CB550 because in its day, the CB550 was renowned for its light weight, nimble handling and magnificent four cylinder engine. This was a standard motorcycle capable of performing well as daily transport or as a stylish corner carver, a perfect base for a café racer build, then and now.
The plan was to keep the style and look of a period café racer but use a few more modern bits that would have existed in the period as relatively exotic specialty parts but have received refinement and mainstream availability today. To that end we took bits from Suzuki’s 85’ GSXR-750, the very first production street legal racer. The Suzuki’s wheels are very light cast aluminum pieces with the requisite 18 inch diameter. These units are wider than the stock CB550 wheels with the added bonus of using modern radial ply tires for a serious performance advantage. We snagged the GSXR fork which is a traditional design but beefy at 41mm, up in size from the CB550’s 35mm. The GSXR fork also offered external compression adjustment which was something very rare in the 1970’s and quite innovative in 1985. We used the Suzuki’s 4 pot calipers and large brake discs to enhance braking power to basically modern standards. A boxed aluminum swing arm with needle bearings from a GS1100 Suzuki model was shortened by 2 inches to keep the 54 inch wheelbase and thus the nimble handling inherent in the stock Honda.
To make our CB550 even more responsive, we used Koni rear shocks from the era but 1 inch longer than stock. This, coupled with the 18 inch front wheel, effectively steepens the steering to facilitate a bit quicker corner entry. We built an aluminum frame brace to tie the frame rails together just below the steering head thus adding stiffness to the frame for hard braking and cornering. The beefy triple clamps we custom built from Billet Aluminum with 45mm of offset to keep the correct front end geometry. We’ve used clip on handlebars with a slight rise to keep the road racer profile and handling precision but still afford a comfortable riding position for everyday use.
The engine received a complete rebuild with a big bore 591 kit and a CB650 cam for a bit more lift and duration. It has a complete Dyna ignition system and over bored carbs now measuring 27.5mm. The bike sports a new Hindle Vintage Racing Exhaust system that is a super lightweight stainless unit with fabulous sound! These modifications will translate into a much more responsive engine, with greatly increased torque and horsepower, but it will still remain a very flexible and reliable unit for everyday use.
The look is traditional café racer with a bump stop seat from the Ducati Imola racer, clip on bars and a knee dent 500T tank. We’ve used Mini Gauge Instruments and a GL1000 headlight shell for a low profile minimalist look. The build has our signature speed holes (reduced weight you know), fat Bridgestone BT45 tires, and fully adjustable rear sets for added comfort.
This is a bike designed to be ridden hard, cloaked in the memories of an earlier time. A machine that most riders could maintain themselves like the café racer of the 70’s did.