Sunday 10 January 2021

Honda CB250RS

The Honda CB250RS is becoming so elusive that it’s almost a classic! I see the odd one still on the despatch. circuit in London. Invariably a real rat - chain churning along the ground, suspension sagging and a smoky, rattly engine. Maybe they’d fetch a hundred notes on a good day. Somehow, they keep on going, doubtless helped along by a garage full of cheap spares - for every one still on the road there must be ten broken for spares. Before I found my machine I'd viewed half a dozen overpriced, well worn out heaps. I admired the optimism of their owners but could only laugh at their stubbornness, and the way they told blatant lies over the telephone.

Even the one I finally found had 29 thou on the clock but the chassis was perfect except for faded, original paint. It was old but had never been ridden in the winter - three owners but all from the same family. Three hundred quid after the usual round of negotiations, against an initial demand for £435.

I knew I was on to a good deal when the vendor came up with the original toolkit, spare cables, workshop manual and a large box of used parts. The workshop manual was heavily greased around the bits on piston and camchain replacement, which gave pause for thought. Sounded just like a typical Honda from the eighties.

To those who missed out on the RS experience, it’s a lightweight 250cc thumper with a thoroughly straightforward chassis layout. Being on the short, squat side I fitted on to the Honda quite well. Flat handlebars well matched to the pegs and a together feel more often found on bigger bikes. The engine performed on a par with a 250 Superdream, which ain't exactly inspiring but more than adequate for town and country work. Even motorways could be cruised at 80mph if some energy was put into the gearbox and throttle.

Of course, you had to learn to absorb the vibes - the engine had a chain driven balancer system that took most of the vibes out when new but wear made it less than perfect. There is, in fact, no way to completely remove the vibes from a single, the art being to redirect the buzz so that the chassis can absorb the worst of it. The tubular frame has to be matched to the engine.

There's always a bit of a thrill, playing with a new bike, during the first few days. The Honda had neutral steering and decent Avon rubber. Combined with its light weight, made for a ridiculously easy time. No hidden nasties. Only that the overall experience was a bit bland - more likely to break the clutch or drive chain than do a wheelie or donut. Singles are supposed to be full of character but even the louder than stock exhaust failed to impress.

Time and mileage went by at a rapid pace, as it does when you're getting on in age. The RS ran up to 36000 miles with no major expenses. Then the camchain rattled away like a box of screws dropped in a washing machine. I'd found no less than three dead tensioners in the boxes of bits. Forewarned, I'd already bought a new tensioner and camchain at an auto-jumble. A good set of piston, rings and barrel were much rarer, the stuff I came across far gone.

One of the joys of running an old Jap is, of course, riding halfway across the land to an auto-jumble, spending an afternoon swapping insults and tall tales with like minded enthusiasts. Much better than dying of boredom in front of the TV. It was just as well that the RS was turning in 70mpg, otherwise I would've been well out of pocket. Cycle parts in good nick were also rare; one of the great coincidences of my life to have the front guard disintegrate en route for an autojumble only to find a better replacement there for all of a quid. Enough to make you believe in God.

The RS came with a pretty marginal front disc when brand new and a decade’s worth of abuse hadn't improved on it any. With the exception of the EBC pads that allowed sensitive braking in the wet.

The caliper is one of those curious Jap designs that corrodes together so solidly that it won't come apart again without doing a self-destruct act. Charmed by such delinquency the average owner finishes off the job with a sledge-hammer. These are as rare as sexy women at autojumbles, although a solution of sorts is to modify the caliper so that a couple of screws can force it apart. Such minor engineering work is beyond most owners. I don't know if the long term effects of wear and winter on more modern efforts allow them to fare any better...

The drive chain’s another short-lived item. A combination of small drive sprocket, odd swinging arm placement and disturbingly thin chain that did nothing to resist the thumper power pulses - old British singles used to have ruddy great shock absorbers on the end of the crankshaft, along with much heftier flywheels.

Needless to say, the high revving little Honda would see off most of that dross. I don’t mean to insult those who believe old British bikes are brilliant, and have yet to forgive the Japanese for what they did in the war, but my own experience of old Brits was not very pleasant.

There are all kinds of solutions to the fast wearing chains. From heavy-duty kits to full chain enclosure but I found the easiest solution was to use the cheapest chain possible, often second-hand, taking links out when necessary. A bit tedious but | had more time than money on my hands. Obviously, this made life interesting, every ride an adventure. The time the chain snapped was quite traumatic. I should've replaced it because there were some pretty obvious tight spots - in one position it was bow-string taut, in another there was three inches of free play.

Anyway, there I was charging through commuter-land, going across a large junction on amber when the thing went. A bit of a bang followed by a rapid loss of speed which I blame on the dragging front disc and slowly deflating tyres. The inner-tubes had more patches than original rubber and the tyres were often worn down to the carcass.

I was about halfway across when all the cars from the side came streaming towards me. They couldn't believe that I wasn't going to get out of their way. The screaming brakes and tyres overcame my own hollering efforts. I tried to urge the bike on as if I was on a horse. Somehow, the cars braked and swerved around me. It was a bad day, a fat porker was waiting on the pavement, and wrote down a long list of offences. Mumbling away that I shouldn't be let loose on the open road. The only lucky thing about the event was that the chain had flown off harmlessly rather than wrecking the crankcase or my leg.


With just over 42000 miles clocked up some very strange electrical antics occurred. Fuses blowing, lights flickering, the battery going dead and the bike refusing to start. Sometimes it'd conk out in the middle of traffic, forcing me to paddle it to the side of the road, amid harsh horns and sibilant shouts. I cursed and threatened the heap but never quite found it in my heart to abandon it.


Not since a brief spell with a GS450 had I been so frustrated. That bike was soon sold as there were no cheap electrical bits for it. After much mucking around, both the alternator and rectifier were found to be on the way out. A complete rewire, used black boxes and battery were necessary, as well as a cheap exchange generator. It took so long to figure out because the - components were only breaking down when they became hot. I had a long argument with one mechanic when I refused to pay him for telling me that there was nothing wrong with it!

After 47000 miles performance became less than scintillating and the vibes only likely to please the most perverse sado-masochist. A worn out balancer chain proved the cause and a used one was fitted, not without a lot of cursing and grazed fingers. The tensioning of this item's best described as pre-historic, making a mockery of an otherwise easy bike to maintain (or more likely neglect).

Yes, the engine will run without the balancer connected but only viable if you want to stand the bike on its end and let it dig a huge hole in the garden. I know this because a lad around the corner had boasted about this trick only to complain a week later that the petrol tank had split open and even the tubular frame was beginning to crack up.

I occasionally bumped into other RS enthusiasts. We’d swap lies about our highway escapades, the longevity of the engine and the size of our spares stashes. I had about half a dozen telephone numbers of people with whom I could swap parts. This is pretty common amongst owners of old Japs, even better than hitting the jumbles or breakers. The only bad point was that I never came across any young women riding old RS250s. The same mix of comradeship and practicality used to exist amongst British bike owners, until the machines were priced out of the game by the greed of the classic brigade. Japanese bikes don't seem to have gone down the same weary road.

53000 miles saw the total melt- down of the motor whilst a lot of the chassis was threatening to rust through. I’m not sure which bit of the motor failed first but the result was a wrecked crankshaft, melted piston and tangled valves. This is pretty common at this kind of mileage unless an unlikely amount of effort has been used to keep the bike in prime condition. Few people seem willing to lavish that kind of energy on the RS.


Foolishly, | bought a motor for fifty quid without hearing it run. It did work but the rattles were so fierce that | knew it wouldn't last for long. Top speed was a reluctant 65mph whilst fuel economy of around 40mpg indicated how far gone was the engine. I ran it like that for two months, shocked that the mill didn’t actually seize up. When my vision started going from the vibes I knew it was time to move on. The RS plus a mountain of spares was sold off for all of £90. I didn't feel cheated, I’d had a few years of good riding, met a lot of people and learnt a fair bit about motorcycle engines. I’m now toddling along on a SR250.


Alan Jones