Motorcycle Restoration Projects

Peter Sutherland has a passion (which is infectious) for both two and four wheels, with several projects on the back-burner. This two-wheel yarn is about a bike he lusted after as a young man when he saw it on the cover of Two Wheels magazine in 1979 – Honda’s iconic CBX six.

Peter started his working life as an electrician and he also loved to play with all things mechanical. Wanting to become more involved in electrical and mechanical engineering, he signed up with the Navy as an Avionics Technician, servicing its fleet of Helicopters at HMAS Albatross in Nowra, NSW.

After more than 22 years in the service he retired in 2019 and now enjoys fettling and restoring his cars and motorcycles.

He’d always kept an eye on the ‘motorcycles for sale’ magazines and electronic sites, looking for a six-cylinder Honda CBX that had a fascinated him all those years ago.  

Finally, there was one on eBay in 2020. The bike was in Newcastle, so he spoke with the owner. Among other things he found out that he’d broken a spark plug in the cylinder head and couldn’t remove it. So, Peter haggled with him and after settling on a satisfactory deal, headed north with a trailer to collect his long-awaited prized possession.

Back in his workshop Peter went about removing the broken plug with an easy-out, but alas, he broke the easy-out in the head. 

“I took the Honda to a specialist engine builder to not only remove the plug and easy-out, but also to check how much shrapnel was inside,” said Peter.

“As it was a major job to remove the engine, I thought the most sensible thing to do was to go-for-broke and have the pros completely overhaul the engine.”

CBX history

Honda led-the-way in motorcycle development in 1969 with the CB750, a bike that was to establish the word ‘Superbike’. The CB750 launch was a signal to the ailing British motorcycle manufacturers, that they were a long way behind in development.

The CB750 is justifiably recognised as a milestone in Honda’s successful invention of the modern motorcycle: a transverse, single-overhead-camshaft, in-line, four-cylinder engine, five-gears, electric starter and front disc brake. 

Back in 1969, nothing else came close. The Poms were all stuck on pushrod engines, four-speed boxes and kick-starters.

However, Honda didn’t have everything its own way and the CB750 was losing sales by the mid-1970s to the other Japanese manufacturers.

Honda’s next step in 1978 was the CBX, with no fewer than six-cylinders across the frame and not a single overhead camshaft, but twin OHC.

Its roots went as far back as the early 1960s, to Honda’s 250cc, six-cylinder, twin-overhead-camshaft, four-valve-per-cylinder race bike, the RC166. It spun the tacho to the dizzy heights of 18,000+rpm, developing some 65hp and had a seven-speed gearbox.

The great ‘Mike Bike’ Hailwood won the 1966 and 1967 250cc World Championships on the RC166 as well as the 350cc titles on the slightly larger, 300cc RC174.

In terms of road bikes, Benelli had beaten Honda to the punch with its series-production Sei 750cc six in 1972, but Honda’s background in sixes certainly gave it plenty of its own ‘cred’.

In his book The Ultimate History of Fast Bikes, Roland Brown wrote:

 ‘Honda’s mighty CBX1100 was the superbike that appeared to have it all. Its 24-valve six-cylinder engine produced a phenomenal 105bhp, making the CBX the most powerful production motorcycle on the road in 1978. Its searing speed was backed by remarkable smoothness and technical sophistication, even by Honda’s high standards.           

‘Years after the bike’s launch, it still inspires great loyalty from a devoted band of enthusiasts.

’It remains a landmark machine, having combined style, technology and performance in a way arguably not seen before or since from Japan.

‘The Six was a handsome machine that had a pure-bred sporting image. It came with a sense of history. having been inspired by Honda’s famous multi-cylinder race bikes of the mid- I960s. And its chassis was excellent, also, boosted by innovative use of weight-reducing materials.’ 

The CBX design engineer, Shoichiro Irimajiri, was the engineer who’d developed the 250cc six-cylinder race bike during the 1960s. The engine provided inspiration for the CBX’s cylinder head with its 24 tiny valves. 

The exhaust camshaft was hollow to save weight and the CBX broke new ground for a standard machine, with its use of lightweight magnesium for several engine covers. 

Irimajiri reduced the potential width of the six-cylinder engine by positioning a jackshaft above the gearbox to drive the alternator and ignition system. This allowed the 1047cc engine to be remarkably narrow at its base. 

Legroom for the rider was provided by tilting the cylinders forward by 33 degrees, and by angling the six carburettors inwards in two pairs of three.

Honda created the CBX as a no-compromise sports bike. Its styling was dramatic, emphasised by the way in which the wide engine, being air cooled and therefore requiring no radiator, was suspended by the tubular steel frame. 

The absence of down tubes added to the visual impact.

Straight-line performance was awesome, combining smoothness with the most ferocious acceleration yet seen from a production bike.

Below 6000rpm the CBX responded crisply but without great force. Above that figure it came alive and surged towards its 2I7km/h top speed with a memorable, high-pitched howl from its exhaust. 

Most riders who rode the big six-cylinder machine were captivated by its unique blend of speed and charisma.

Its chassis worked, too. The CBX had good quality suspension, plus efficient, twin-disc front brakes. 

Weight was kept to a minimum by use of aluminium handlebars, plastic mudguards and magnesium engine parts. Although the Honda still weighed a substantial 259kg that meant it couldn’t match the composure of Suzuki’s new GS1000 four, it handled well for such a big bike.

But for all its pace and panache the CBX sold very poorly, especially in the vital American market. The principal reason was simply that the Six cost far more than its less-exotic rivals. In some markets it was 50 percent more expensive than similar-sized fours yet offered no real-world advantage in terms of achievable performance.

After a 1981 redesign that created the fully-faired CBX IOOOB, in an attempt to add appeal for long-distance riders, the Six was dropped from the range. 

Honda’s six-cylinder gamble had failed. 

But the CBX had given the firm’s image a considerable boost, as one star-struck tester put it in 1978:  ‘The Six is one of those rare machines that will never, ever be forgotten. As long as fast bikes are ridden and admired, there is absolutely no danger of that’.  

Peter Sutherland’s CBX was in pretty good nick, apart from the engine dramas, but he has planned to fit a customised six-into-one exhaust system, not just for aesthetics, but to give it a more enthusiastic tone.

We’re not sure that’s necessary, because when he rode off up the road after our photo shoot, he cranked the throttle and increased the pitch to crescendo level that would make an angel cry!

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