Honda RC165 250cc six-cylinder at the TT
Honda revolutionised motorcycle racing in the mid 60s with the arrival of the truly incredible mechanical masterpiece that was the RC165, and then quickly improved on it with the RC166.
The crankshaft was a 13-piece item and the 41 mm pistons spun through a 31mm stroke to 18,000 rpm. This is some amazing engineering from more than half-a-century ago complete with double-overhead camshafts operting four-valves per-cylinder. A bank of six 22 mm Keihin carburettors fed the engine. It had a seven-speed gearbox and if you held on long enough could reach almost 250 km/h.
After dominating with this design and setting a new standard in motorcycle engineering, Honda then stepped away from Grand Prix motorcycle racing and took what they had learned with this project across into their foray into Formula One.
Check out this incredible exploded diagram below and remember that for scale, the entire engine is only around 350 millimetres wide… Then below the picture, click the video to take a demonstration lap around the Isle of Man TT with Steve Plater, followed by another video that gives your ears a tune-up as to how incredible this thing sounded.
It is quite simply, an incredible masterpiece.
Honda RC165 lap of the IOM with Steve Plater
Listen to the cluch slip required to keep that thing spinning at low revs. It does not appear to be fuelling all that well and would have been ridden harder during the heated battle of competition by the likes of Mike Hailwood back in the day. But I certainly don’t blame Steve for taking it relatively easy for a demonstration lap on what is an almost priceless machine, and especially when wearing the old school attire to boot!
I imagine even for Steve it felt like quite an honour to ride such a magnificent machine around the Isle of Man.
Check out a good demonstration of the sound in this further video below.
