Wednesday 6 November 2019

Honda CB650


I had spent hours trying to get the oil filter off. The bolt was mashed beyond hope. I had to take a chisel and hammer to the filter body and whack away violently until the whole thing was reduced to a pile of rubble. Murky, white-grey oil slithered out of the engine but there were no disturbing bits of engine amid the lubricant. There was, at least, some hope that the 23000 mile engine had some life left. After a new filter, housing and bolt were bought, the engine was flushed clean and new oil added.

I was impressed by the quiet whirr of well oiled bits. A 1980 machine, the CB650 Honda had evidently had some hard times but survived them well. The local dealer had taken the machine in part exchange and let me have the bike for £500 before his mechanics had a chance to transform it into something more saleable.

I had blown a couple of weekends sorting the Honda out, adding new consumables and dealing with the damn filter (a common OHC Honda fault). Much to my surprise, the valves and carbs had been correctly adjusted whilst the non-standard electronic ignition needed no attention.

For a 650cc OHC four that develops only 60 horses I found the engine surprisingly peaky. It did not like to run below 3500rpm in fifth gear and needed a handful of throttle to avoid stalling on starting off. This rather belied the machine’s image as a staid tourer and often made the bike a pain in the arse to ride after a long day’s ride, when all I wanted was to relax by letting the CB650 slog along in a tall gear. No hope of that.
 

The transmission was the usual Honda mess, lacking in predictability until you became used to carefully feeding it through the box. First to second was by far the worst aspect of the change, usually putting the bike in a rev mad neutral. Conversely, clutch drag in slow moving traffic meant neutral was almost impossible to find. The first few months were fraught, the engine’s insistence on revs making use of the gearbox mandatory, but I eventually became used to its nastiness.

Between 60 and 90mph in top the engine was at its best; both smooth and prodigious in its output of power and torque. The engine would happily hold a 90mph cruise up steep hills and against strong winds. There was a useful edge in acceleration thereafter up to an indicated 115mph when a kind of plateau was reached that could only be broken by a long road or downhill section. Several times I managed 125mph on the clock, but the secondary vibes once past 90mph made it a poor experience that I was in no hurry to repeat.

Also, beyond 90mph fuel consumption took an astonishing dive from an acceptable 45mpg to a mere 28mpg. As long as speed never broke the 90mph barrier, 45mpg would work out as the average. In fact, even cruised mildly the bike still did 45mpg. Only on a few rare occasions did the CB manage as much as 50mpg, usually with a howling gale of a wind behind us. This is probably down to the weird lack of torque below 3500rpm and a transmission that lurched so badly at low speeds in top it must have been highly inefficient. The combustion chamber design was inherited from the old 500 four so was probably not too efficient at this much larger capacity.

The suspension and steering geometry also dates back to the early seventies in inspiration. However, there was none of the sogginess that I had expected the front forks had been modified and the shocks exchanged for a set of Konis. The result was a taut feel more usually found on big British twins.

At 450lbs the staid geometry meant much muscle was needed to carve a fast path through the bends. The 4-1 exhaust someone had fitted carved chunks out of the tarmac when the bike was ridden hard through the lanes, but at least the side stand was tucked well out of the way and the centre stand junked. Older Honda fours have a habit of digging in their stands, lifting the back wheel off the ground and throwing the rider in a ditch.

The tubular frame appeared straight and reasonably strong around the headstock and swinging arm pivot. Smooth roads the Honda could hack reasonably well... there was always the odd bit of fluttering from the back end but nothing malignant like you might find in an early CB750 four, to which the 650 is surprisingly closely related. It was when the road turned rough that the admittedly nonstandard suspension refused to cope. Road oscillations were fed directly into the frame which reacted by either shaking its head or twitching its tail.

On reasonable tyres (newish Avons or Michelins) most of the wobbles could be ridden through with little fear of the consequences. With my self imposed limit of 90mph I had little to worry about. On worn tyres, though, it was an entirely different matter. The bike would undergo violent, vicious speed wobbles that left the bars twitching from lock to lock and the machine leaping from one side of the road to the other. These wobbles occurred at as little as 50mph and as much as 100mph. I soon learnt to replace the tyres once they were down to 3mm (which took 7-8000 miles).

Once I had become accustomed to these problems I found the bike useful in a variety of roles. It was cheap and robust enough to use all year round as a get to work and back hack. Over time, I became impressed by its general ruggedness. Carbs and valves needed minor attention every 5000 miles, oil was changed every 1000 miles and that was about it engine-wise.

After a few months of commuting I was happy enough to take the bike touring round Europe. The machine whirred through several countries without giving any problems. Its tireless nature was spoilt by a rotten riding position tor fast work (bars too high, rests too far forward) and a seat that turned to a bed of nails after 70 miles (it also soaked up water like a sponge). I was much relieved each time a petrol stop was necessary.

The weather was fantastic, though, which made most things more than bearable. The first winter revealed a front disc caliper that hated water and cold as much as myself. Seizing solid with the brake hauled on was its favourite trick that not even several strip downs managed to cure. A replacement from a breaker fared no better, so I paid out for a new ‘un. After all, it didn’t seem worth spoiling the dependable nature of the bike by suffering the aged brake caliper.
 

Slowly, I replaced bits like bars, pegs and seat to turn the bike into a more useful, comfortable tourer. It didn’t cost that much and made a hell of a difference to the pleasure I got out of taking the Honda on long runs. | even began to curse the 120 mile range of the petrol tank as being too small, such was the improvement in comfort. The longest day’s ride was up to Scotland in the spring, 700 miles of excellent fun. I didn’t half sleep well that night, though.
 

I had the bike for three years, adding 41000 miles to the clock. With 64000 miles done the engine still ran with incredible reliability (all those regular oil changes and lack of thrashing, I think). Even the camchain tensioner still worked, which is a minor miracle for a Honda four of that era. The frame needed constant attention as paint kept falling off, but tank and panels were still in reasonable shape. Both guards had been replaced with plastic items after a minor spill sent the bike sliding down the road, but serious damage was limited by the engine bars. The handling became no worse.
 

I liked the Honda a lot. It had so many weird mannerisms that it never became bland like so many Japanese fours. I revelled:in the reliability of the engine, feeling I could always jump on the machine and be assured of reaching my destination, be it a few miles or across a couple of continents! Running costs were a bit high for the kind of speeds employed but the lack of engine attention needed and low purchase cost meant it worked out as good value. Indeed, I got £750 when I traded the bike in for something bigger and newer.
 

There are other fours of the same period which are faster and just as reliable. But the Honda was cheap to buy, easy to work on and fast enough to be interesting. The CB650 is not rated highly in some circles but I found little to complain about in my machine.

Paul Newnes