Stuck in the Middle: The 1977 Honda CB550K

About 12 years ago, Mark thought it would be interesting to restore some of the machines he wanted when he was a teenager but couldn’t afford — namely, Suzuki 2-strokes like the GT380, GT550 and GT750. He purchased examples of each, chased parts and eventually had three pristine Suzukis. When they were done, Mark enjoyed them for a few years and then donated them to the National Motorcycle Museum in Anamosa, Iowa.

Then, about two years ago, the collecting bug hit him again. That led to a search for another mid-1970s motorcycle project. And this is where Mark’s sense of nostalgia enters the story. When he was 16 years old, his uncle, Lynn Blanchard, bought a brand-new Honda CB550K. “I rode the bike just after he bought it, and I thought it was the biggest thing on the road,” Mark recalls. “I mostly rode Suzuki and Yamaha 2-strokes back then, and I didn’t really think too much more about the 4-stroke CB550, except for keeping the memory alive.”

From CB500 to CB550

Honda introduced the CB550 late in 1973 as a 1974 model-year machine. The CB550 replaced the CB500, which ran from 1971 to 1973. In the December 1973 issue of Cycle magazine, the editors wrote about the newly minted CB550: “… thousands of motorcycle riders would think the [550] is still the same machine. It is far from the same. Solutions to two major problems on the 500 and a few other smaller improvements make the 550 a considerably better motorcycle. Fixing the 500’s two big flaws — an ill-shifting transmission and a clutch sometimes prone to slipping — makes the biggest difference in the 550 aside from a bit more mid-range,” they said.

The CB550 was equipped with Honda’s single overhead cam, 4-stroke, transverse 4-cylinder engine. With a bore and stroke of 58.5mm by 50.6mm, the powerplant featured a 9:1 compression ratio. Fuel and air were mixed in four 22mm Keihin carburetors, and four exhaust headers led to four separate mufflers — two on each side of the machine. The engine was placed in a dual-downtube cradle steel frame, and the front forks were upgraded from piston-valve to the free-valve type to help alleviate wear. Atop the fork, the 550 now had the same instruments that graced the CB750. New hand control switchgear included an audible beeper to remind riders to cancel their turn signals, a love-it-or-hate-it feature that many owners eventually disabled.

Brakes consisted of a single disc up front and a drum out back, complete with a visual wear indicator that had a red line on the backing plate and a red arrow on the brake actuating arm — when the arrow pointed at the line, the shoes needed to be renewed.

The Cycle test ended succinctly. The editors suggested that a then-current owner of a CB500 need not trade up, nor a CB750 owner trade down — unless the weight of the larger motorcycle was an issue. “Should a new rider buy a 550 Four? You bet. And you’ll love it.”

Colors galore

The 1974 CB550K0 came in three colors; Flake Sunrise Orange, Boss Maroon Metallic and Freedom Green Metallic. The gas tank was two-tone, featuring the base color and black side panels accented by a gold stripe. The side panels were finished in the base color. In 1975 the CB550K1 featured dark green instrument faces. Paint was Candy Jade Green or Flake Sunrise Orange with a black and gold tank stripe. The tank stripe carried over to the 1976 CB550K2, and it was finished in Candy Garnet Brown.

For the 1977 CB550K3, Candy Garnet Brown was still available, together with a new Excel Black scheme. Both colors were set off by a wide stripe in red and gold, and the fuel-filler cap was now hidden under a locked cover while the side cover emblem indicated “550 Four K.” Honda dropped the signal light beeper in the handlebar switch for 1977. The last year for the model was the 1978 CB550K4, which came in Candy Alpha Red and Excel Black. A new stepped seat altered the profile of the machine.

A sibling joined the CB550K in 1975 when Honda launched the CB550F. Styled in the café racer “Super Sport” line, the F models had a four-into-one exhaust system and a different gas tank and seat. Engine specs weren’t much different between the 550K and the 550F, and the sportier model lasted just three years, with production ending in 1977.

Problems within

Mark’s interest in transverse fours was rekindled when a 1977 Honda CB550K turned up for sale in Walneck’s Classic Cycle Trader — it was a similar model to the one his uncle owned. The Honda was located in Georgia and was represented as an original, 11,000-mile machine. Mark bought it sight unseen, but was disappointed with its condition upon delivery. “It was a mess, and it certainly wasn’t rideable. It sounded more like a threshing machine rather than the refined sound of a 1970s Honda 4-cylinder. The Honda fours were sewing machine quiet.”

A rattle-can restoration wouldn’t do for Mark, so he searched for somebody who cares as much about restoration excellence as he does. He found Brady Ingelse of Retrospeed in Belgium, Wisconsin. Retrospeed is a full-service repair shop catering to both modern and vintage machines. Brady’s shop also specializes in complete, concours-quality overhauls. That’s what Mark wanted; a fresh, off-the-factory-floor restoration.

“The bike Mark sourced looked great from 10 feet away, and we thought it was a great core for a rebuild,” Brady says. “Unfortunately, the Honda had been restored once before, and many problems were hidden within.”

Before diving into the restoration, Brady started the Honda. The CB550K’s engine made an ominous growling noise, and was quickly shut down. After getting the engine out of the frame and digging into it, Brady found the noise was the field coil, which was simply rattling around under the side cover. Further, parts that should have been painted were chromed or polished — or vice versa. According to Brady, it was a train wreck.

To make the CB550 a concours-quality restoration, no aftermarket or reproduction components were sourced. Every new part is either directly from Honda or was located as new-old-stock from suppliers such as David Silver Spares or CMSNL. The cables, gaskets, footrest rubbers, grips, fork stanchions and spokes and nipples are all new.

The frame was clean and straight, but the VIN tag had been previously removed and reaffixed with screws. Brady welded in the screw holes and drilled the area to accept rivets. The center and sidestands were in rough shape, as the motorcycle had obviously gone down on its left side, resulting in serious scuff marks in the metal. Brady sourced new replacements and sent the frame, swingarm and stands out for powder coating.

The forks were rebuilt using the new stanchions, while the fork sliders were polished to the original luster and used headlight ears were sourced and chromed. The original DID wheel rims were replated and then laced to media-blasted hubs with new spokes and nipples. With the wheels together, new Continental Twins Classic tires, RB2 front and K112 rear, were levered into place. The rear shocks were actually in good shape, but Brady took them apart to polish the bodies and collets before putting them back together with the original springs.

Polishing time

The instruments were restored and some lenses, such as those on the signal lights, were replaced. According to Brady, many of the Honda rear taillights, which were produced by Stanley, are prone to rusting in areas that are difficult to access and properly restore. The original metal bodies were pressed together and then spot-welded. On this CB550K, Brady cut the body apart, had the pieces chromed and then carefully TIG-welded the assembly back together. The red plastic bulb cover was polished in-house to make it appear brand-new.

“We do all of our own blasting and polishing to ensure we get the correct finishes on these motorcycle restorations,” Brady says. That includes all of the engine components. On Mark’s CB550K, the cases were powder coated a silver color that’s as close to factory Honda as Brady has been able to get. “We’ve spent a lot of time getting the silver powder coat just right. When it’s done, it looks like a brand-new Honda engine,” he says. The cylinder and cylinder head were also powder coated to give them the appropriate dull finish. Inside the engine, the crankshaft plain bearings were in good shape, but one of the transmission bearings felt notchy and was replaced. The top end was in fine condition, and was simply cleaned and reassembled. The engine side covers were polished and then taken to a brushed finish.

The carbs were cleaned in an ultrasonic bath, and then all of the levers and linkages were either clear or yellow zinc-coated by Oshkosh Plating Technologies in Wisconsin to original specs. The float bowls and carb caps are a lightly polished, brushed aluminum finish that Brady replicated on his buffing wheels. Even the front brake master cylinder has been reanodized to the correct Honda color. USA Anodizing in Milwaukee, Wisconsin, did this job.

Paint and exhaust

Brady worked with the original exhaust system, spot-welding holes in the mufflers and grinding the surface smooth in preparation for chrome plating. Larger dents in the header pipes were filled with weld and ground smooth, too, before being dipped in nickel and then chrome.

The gas tank and side covers were painted the original Excel Black, while new emblems came from Badge Replicas in Australia. After talking to many different people about whether the warning decal on the gas tank should be on top of or under the clear coat, Brady learned the sticker goes on top. The Upholstery Shop in Fredonia, Wisconsin, installed a correct Honda cover on the seat.

“This motorcycle is quite awesome to ride,” Brady says. “It’s a little milder and there’s less vibration than on other inline fours. In town and just scooting around, it’s a phenomenal machine.”

And that should work out just fine for Mark, as he plans to ride the CB550K at least a few hundred miles every year. Of the finished machine, Mark says it’s everything he expected it to be — like a brand-new mid-liter Honda — and he’s quite happy to be stuck in the middle with this one. MC