- Engine: 1,047cc air-cooled DOHC 4-stroke 6-cylinder, 64.5mm x 53.4mm bore x stroke, 9.3:1 compression ratio, 103hp @ 9,000rpm (at the crank, 85.5hp at the rear wheel)
- Top speed: 136mph
- Carburetion: 6 Keihin 28mm CV
- Transmission: 5-speed, constant mesh, chain final drive
- Electrics: Battery-powered solid state CDI, 12-volt alternator
“That engine!”
Scott Mercer is referring to the 6-cylinder powerplant found in the legendary Honda CBX. It’s a mill that has long fascinated him, but a strong sense of nostalgia also plays a vital role in this story about his 1979 Honda CBX.
It all starts in the early 1970s when Scott’s stepdad, Russ, got a once derelict Aermacchi-built 250cc Harley-Davidson on the road again. “It was a non-running machine,” Scott recalls of the Aermacchi. “My mom actually paid a shop to put it back together, and he taught me to ride that bike — that launched my motorcycle career. Russ was passionate about motorcycles, and I followed closely in his footsteps.”
In 1978, the year Scott graduated from high school, his mom and stepdad bought him a 1972 BMW R75/5. He rode it extensively, but the machine was a little tired so he took out a $1,000 loan and freshened up the BMW’s engine and transmission. Sadly, while riding home from AMOL Precision, a motorcycle shop located in Dumont, New Jersey, an errant driver took out the front end of Scott’s machine. The bike was totaled. To pay off the loan and accumulate enough cash for a down payment on a new BMW R80/7, Scott worked two jobs for a number of months. AMOL was running a special in conjunction with BMW of North America on the R80/7, and it included the $650 option of a Luftmeister fairing and Krauser bags at no extra cost. Scott says he jumped on that deal, but shortly after his purchase Russ arrived home on a brand new 1979 Honda CBX in Candy Glory Red.
“I was gobsmacked by the CBX,” Scott says, but adds he couldn’t afford the $4,000 price tag of the Honda so continued riding his BMW. “We would ride to BMW MOA National Rallies, me on the R80/7, my mom on her Honda CB400A Hondamatic and Russ on his CBX, with that engine!”
Fast forward to 1983. “By this time, I’d read that Honda had leftover CBXs sitting in dealer warehouses because they couldn’t sell them,” Scott explains. “So, I managed to source a brand new, in the crate, zero mile, ’79 CBX in Perseus Silver from Honda Mineola Long Island for $2,850. It was a four year old, brand new machine.” By this time married with a young family, Scott says life was humming along and he enjoyed riding the CBX but he began hankering for something a little sportier. In 1991, he sold the CBX with 11,000 miles on the clock and replaced it with a Kawasaki ZX11. Perhaps that was just a little too sporty. “I was a young fool and I was going to kill myself on that thing, so in 1992 I bought a BMW R90S in Daytona Orange.”
From BMWs back to the CBX
After that, Scott’s motorcycles were mainly BMWs but his interest in the CBX never really waned. For close to 20 years, he kept track of the CBX market and says about 10 years ago he reached out to TIMS CBX (Tim’s International Motorcycle Supply) in Georgia expressing an interest in purchasing a restored Honda. His timing wasn’t good then, but about a year and a half ago, Scott reached out again to TIMS with the intention of buying a CBX.
“A 1979 CBX in Candy Glory Red out of South Carolina had just come in on consignment,” Scott recalls. “It had been restored five years earlier by TIMS, and the owner had put only 500 miles on it. He wanted to move it; we agreed on a price and I had it shipped here to my home in Pennsylvania.”
Upon delivery in September 2021, Scott was pleased with his purchase and put a few miles on the CBX, but says he wanted to go just that much further with the bike to make it the Honda he remembered from the early 1980s. “I embarked on a journey to make it exactly what I envisioned and remembered of those early CBXs,” he says.
Looking back
Introduced to journalists late in 1977 in prototype form, Honda’s CBX was something completely different in the motorcycle marketplace. “Even in the age of superbikes, nobody could believe it when Honda unveiled the CBX Six,” notes a review of the bike in the January 1979 issue of Cycle World. “More cylinders, more camshafts, more horsepower, more speed, more acceleration, more more. It was the fastest, quickest, flashiest, most head-turning two-wheeled street vehicle ever seen.” In 1978, when Cycle World tested a prototype CBX, the magazine proclaimed the model was the fastest motorcycle it had ever tested. In 1979 production trim, the CBX was even faster, clocking an 11.36 second run down the quarter mile at 118.11mph.
And it had every right to be fast. The CBX project leader was Shoichiro Irimajiri, who, in his mid-twenties, drew up GP racing 6-cylinder engines in 250cc and 297cc capacity. He was also the mastermind of a twin-cylinder 50cc engine with a 23,000rpm redline and a 125cc 5-cylinder. Irimajiri was quoted in the February 1978 issue of Cycle. He said, “When we were racing, we were up against the 4-cylinder 2-strokes built by Yamaha and Suzuki. Cylinder multiplication was the only way we could be competitive. That’s why we built the Five, and the two Sixes.” He continued, “The CBX-Six is a direct descendant of those race engines.”
Honda’s 1,047cc CBX 6-cylinder powerplant featured twin overhead camshafts and four valves per cylinder. The manufacturer was proud to announce those last two facts on a tank-top decal, declaring the CBX 6-cylinder was a “Double Overhead Cam” and had “24 Valves.” Bore and stroke was 64.5mm by 53.4mm with a 9.3:1 compression ratio. Each cylinder got its own 28mm Keihin CV carburetor and an impressive 6-into-2 exhaust system handled spent gases. To keep the engine relatively narrow, ancillary components such as the ignition system and alternator were mounted behind the engine’s cylinders instead of at the ends of the crankshaft. Compared to Honda’s CB750 4-cylinder, the CBX’s 6-cylinder engine wasn’t much wider, measuring only 40mm broader.
All six cylinders were canted forward and the engine acted as a stressed member in the tubular steel frame. Front suspension was telescopic fork and, for the first two years of production, twin rear shocks provided rear suspension. Rolling stock consisted of aluminum 5-spoke wheels, a 19-inch rim up front with twin disc brakes followed by an 18-inch hoop out back with a single disc. Although Honda employed weight-saving materials throughout the CBX, according to the January 1979 Cycle World test the machine still tipped the scales at 580 pounds with half a tank of gasoline.
Honda’s CBX was intended to be a sporting motorcycle, and for the 1979 and 1980 production years that’s how the machine was marketed. The 1980 models gained air adjustable forks and the twin rear shocks also became adjustable. For 1981 and 1982, the CBX took on a different persona as a sport touring motorcycle. The engine was slightly detuned using altered camshaft profiles to put more usable power in the midrange. Suspension was changed to a single shock Pro-Link rear and the fork tubes were made beefier, as were the brakes. Honda took some flex out of the chassis tubes and strengthened the frame. Topping off these changes, Honda installed a wind-cheating fairing and a pair of saddlebags.
In his Retrospective column, moto-journalist Clement Salvadori noted in the October 1996 issue of Rider magazine that the CBX did “Everything well … except sell. Somehow it did not strike a chord in the hearts of motorcyclists. Everyone admired it, everybody wanted to ride it, but few people were buying it.” Even after the redesign, turning the CBX into a sport-touring model, Salvadori says the bikes just weren’t selling and 1982 was the last of Honda’s 6-cylinder CBX.
“The frame is not terribly robust,” Scott says of the early CBXs, “and the forks (with 35mm tubes) are spindly, too. But the bike has an incredibly sporty nature, once the engine hits 6,000rpm it really scoots and the package is very smooth, and very comfortable.”
Dialing it in
About a week after he got his new-to-him Honda 6-cylinder nostalgia machine, Scott asked a CBX-knowledgeable friend to help make a few changes. “He agreed to take it apart and scrutinize everything for Honda factory accuracy,” Scott explains. Once completely dismantled, it was discovered the engine case was from a slightly later CBX. To make it more correct, an engine case made the same month as Scott’s frame — identifiable through serial numbers — was sourced and all parts were swapped. All of the motorcycle’s nuts and bolts were cleaned and re-plated. Aftermarket rear shocks were swapped out for a pair from Honda.
To bring the instrument cluster up to his standard, Scott sent the gauges, which include speedometer on the left, tachometer to the right and voltmeter in the middle below the larger dials, to CBX Performance in Costa Mesa, California. There, the instruments were taken apart, cleaned and lubricated, calibrated and finished off with what CBX Performance describes as “exact reproduction faceplates” that “are NOT a cheap sticker or decal, but an actual replacement plate virtually identical to the OEM plate.”
With the CBX’s dash looking brand new, Scott managed to source brand new handlebar switchgear to add to the lower handlebar that’s part of Honda’s highly desirable Sport Kit. This kit came with shorter cables for clutch and choke and the throttle housing was different, too, with cables originating from the top rather than the bottom. Scott’s CBX also has the Sport Kit’s rear set controls with different footrests and gear shifter linkage. The paint on his CBX, in the Candy Glory Red that Scott remembers of his stepdad’s bike, was done very well and needed no attention. With all revisions to the CBX being done over the winter, Scott’s machine was returned to him in April 2022.
“By old bike standards,” Scott explains, “it’s a breeze to start. Put the key in the ignition, but don’t turn it on. Turn the petcock on, open the throttle several times, put the choke on, turn ignition on and hit the start button. It fires up every time.” He’s added about 800 miles to the odometer since its refurbishment, and while it’s not a daily rider, he concludes, “It is a cream puff motorcycle that I want to work, because I want to be able to ride it and I thoroughly enjoy it. The sound, the feel, the acceleration, that engine, it all brings to me instant memories of my first ’79. And it really is an ode to my stepdad, Russ, that I have this bike.” MC