Saturday, 19 June 2021

Honda CB500/4

Honda’s CB500 four is an example of poetry in motion. A sheer joy to look at in its perfect proportions and classic silhouette. Unlike the early CB750 four there’s not so much mass as to make it dangerous in the bends and the smooth, linear flow of power never threatens to throw the tyres off line. In the seventies it was the perfect machine to move up to from a then learner legal 250 twin. That's what I did back then, and I had a really enjoyable three years and over 23000 miles out of a four year old CB500. After a series of ever faster and more complex Jap iron I ended up with an FZR1000. An absolutely lovely bike, perfect in almost every way... except that I was becoming very annoyed with the ever increasing cost of insurance. The CB500 is considered a classic as far as insurance goes and one of the low mileage policies can be picked up for a fraction of the cost of FZR insurance. All I needed was a suitable bike and I'd be able to relive my youth.

The FZR was sold to a youth who reckoned he was going to ride without insurance. A running if rat '73 CB500 turned up for £200 a week later. 63000 miles, a few camchain rattles and the most rotted exhaust system I’d ever seen - it may well have been there since new. After the FZR, the Honda felt very bland, more like a 250 Superdream than a 500cc OHC four, but then after the 170mph Yamaha just about any bike would feel like a slouch. There was also a lot of ribbing from my friends who found the Honda, resplendent in a sort of gunge brown and rust, truly hilarious. A feeling accentuated on the first run when the seat fell apart and the chrome front guard disintegrated: The seat was repaired with a couple of rolls of insulation tape and a bit of wood. The guard was so far gone that by the time I pulled over there was nothing left to repair.

Apart from these minor and entirely predictable incidents, the CB would still put a ton on the clock, cruise at 80mph and hold its own in the corners. I spent another 200 notes on bits to put the machine to rights, including a new camchain and tensioner, used guards, tank, seat and four into one exhaust. The protective layer of grime left the engine cases and frame in reasonable shape, which was highlighted after I sprayed the guards, tank and panels a deep, gloss black.

Back on the road, my friends were amazed at the transformation from rat to classic bike. The largest of them demanded a test ride, came back with a rattling clutch and clanging front disc. He was too big to hit but I was tempted after he muttered, something about coming out the other side of the red zone and nearly knocking down a pack of pedestrians when he suddenly needed to lose 100mph fast.

The clutch slipped above 5500 revs and the front disc barely worked, not that it could ever be called a stunning stopper even when newish. I had to re-educate my right hand as it'd become soft from the FZR that just needed a finger or two whereas the Honda demanded an iron grip. The rear drum was quite adequate but tried to pull the wheel out of the swinging arm when used in corners, disconcerting rather than dangerous.


Used CB500 calipers were not widely available so I stripped the old one, cleaned out all the brake dust and reassembled. A set of EBC pads were offered up along with new brake fluid. It worked but still needed a gorilla grip and had a momentary delay in the wet. Pushed really hard, used repeatedly from high speed stops, there was a bit of fade and enough heat off the disc to scramble an egg. Pattern clutch plates, after the obligatory bit of filing, were tenderly placed in the drum which benefited from having the burrs removed from the slots. Praise was lavished on the previous owner for fitting Allen bolts, although one of the recesses began to open out when I tightened down the bolts. I felt a lot of pressure was necessary to compensate for the Hermetite smeared old gasket. I'd given the Honda dealer the finger when he quoted me the price for a new one and pattern gasket makers sometimes blocked off an oil-way.

Piranha electronic ignition was already fitted, which made starting easy but may have accounted for spark plugs lasting no more than 2500 miles. The first time it happened I thought something serious was amiss as two cylinders went down. At a certain point in their wear, wet weather riding caused the engine to cut out on to two or three cylinders. New plugs solved this. Wet weather faults are not uncommon on this model, but my bike was running non-standard coils, HT leads and plug caps, as well as the electronic ignition.

Maintenance was a 1000 mile matter of doing oil, filter, eight valves and four carbs. Once I knew my way around the machine it only took an hour or so. They do need this frequent care unlike, say, a GS550 which can be neglected for 5000 miles or more. The only major hassle I had after sorting the clutch was the starter motor which jammed up, made a noise like the engine was falling apart. There’s a kickstart so I could’ve thrown the whole mechanism away but I liked to have the electric boot to hand in case I stalled in traffic. A used starter and clutch mechanism were found for £20, off, I think, the CBS550F model. Many Honda parts are interchangeable across models and as my bike already sported a non-standard exhaust, seat, suspension and bars I wasn’t too concerned about originality but I did want to keep the overall shape intact, though.

I did about 4000 miles before I had a big problem with the chassis. The back wheel started breaking up. By the time I pulled over as well as broken spokes (I was never able to clean the rust off them) the drum casting had cracks running through it. At this point I also found that the swinging arm bushes were shot and part of the swinging arm looked like it was rusted right through. The cosmic exchange system turned up the bits I needed, including a pair of wheels with alloy Borrani rims and a newish set of Dunlop tyres. Almost made the two hour wait for the AA worthwhile.

Then I had to suffer a boiling battery that almost gave me a third degree burn when I tried to pull it out. The gurgling acid sounded evil and did nothing for the finish of the surrounding chassis. Blowing bulbs indicated that too much voltage was getting through. The regulator was burnt out, due to a couple of wires shedding their insulation. It was pretty obvious that the whole bike needed a rewire. I was lucky that the electronic ignition hadn't gone up in flames. A mate was handed a very reasonable sixty quid with instructions to get the electrics sorted. I even went to the trouble of uprating the headlamp because the stock unit ain't much cop above 30mph on country roads. Even with decent electrics, batteries don’t last much more than eighteen months, which is strange as the engine’s pretty smooth and I don’t rev much past 9000rpm.

Even with the 80000 miles now on the clock, the engine has maintained its smoothness, civility and reliability. I don’t know what work was done before I acquired the machine, presumably there was a re-bore done and maybe a top end overhaul. Most Honda fours of this era need some serious attention after 50000 miles of abuse, or a lot less than that if regular oil changes weren't done.

In the time I’ve had the Honda I’ve grown to realise that the excessive power of newer bikes isn't really necessary to enjoy the larger motorcycle experience. At least in the UK, the CB500’s power is perfectly matched to the road conditions, as is its mass and agility. Also, the design is so simple that it’s very easy to understand and work on. It’s relatively effortless to make minor chassis mods to tailor the bike perfectly to my own needs. If, for instance, I decide I don't like the bend of the bars I just hit the nearest breakers for a different set and half an hour later I’m back on the road. Try that on an FZR!


Of course, the plastic replicas have gut churning acceleration that burns deep into the soul and is not so easy to forgo. But I don’t think it’s worth the cost in consumables, insurance and maintenance. The Honda keeps cheap tyres and chains going for over 12000 miles, pads for 15000 and costs nothing except oil to service. Funnily enough, fuel consumption worked out the same for both bikes, around 40mpg. A low mileage CB500 might better that but don’t expect more than 50mpg, something to do with the friction of all those moving parts.


Finding a nice CB500 four won't be easy and good ones can fetch more than a thousand notes. My engine must be due for serious attention soon but that's no problem as I've acquired a low mileage CB550 motor in readiness hopefully, I’ll do the swap before the old engine blows up or seizes. I don't think they will ever make four cylinder bikes this simple again. More’s the pity!


J. D. T.