Gez takes a purchase-focused look at an entry-level four-stroke twin – the Honda CB250K series

Honda’s well-built, reliable workhorse is underrated – and makes an ideal starter classic. But get in quick, the word is getting out...

Once ignored as ‘just’ a cheap and cheerful learner bike or commuter, Honda’s CB250K is, at last, being properly appreciated. To be fair, the classic racing boys have been in on the secret for a while, snapping up every decent example of the CB250’S big brother, the CB350K and turning them into freakishly fast race bikes. Now it’s a job to find a good CB350K in road trim. So maybe the next best thing is the 250 version. But, if you fancy one, be quick – prices are shooting up and some mint examples are being offered for more than £4000. The CB250K0, launched in 1968, was the long-awaited replacement for the CB72. While the CB72 had done great business for Honda, it was starting to look its age by then. The new 250 was pretty well allnew – and it looked it.

A tubular, single-downtube frame replaced the pressed steel item of the earlier model (though there was still a pressed-steel section behind the engine) and the engine sat almost vertically in it, for a start. But the changes were more than skin deep. The CB250K0 and its 350 (325.6cc to be exact) stablemate share the same bottom end, with a four-bearing 180° crank with central chain drive to the overhead camshaft.

The camshaft ran in a separate cam box bolted to the cylinder head, and the rockers pivoted on eccentric shafts that rotated to adjust valve clearance, while a fivespeed gearbox helped make the most of a claimed 30bhp at a heady 10,500rpm. Primary drive was by straight-cut gears, CV carbs were adopted and there was a new, plunger-type oil pump. All in all, it was a much more modern package than the old CB72/77 mill.

The cycle parts were conventional enough, though. The front brake was still a decent, workmanlike twin-leading-shoe drum and the forks were conservatively shrouded. But a separate speedo and rev counter plus more imaginative colour schemes helped make the CB250 look ready for a new decade. External changes were minimal for the first six years of production. Some early camshafts failed, due either to faulty heat treatment or oil starvation caused by pieces of unsupported gasket material breaking off and blocking the oilways, and the hydraulic camchain tensioner fitted to the first models was swiftly replaced (many units under a warranty recall) by a revised, spring-loaded design. But once those few teething problems were resolved, most CB250S proved admirably resilient to the harsh treatment meted out by thousands of learner riders.

The first big change was the introduction of the G5 model in 1974. The G5 had a six-speed gearbox, a front disc brake and racy upswept silencers, but it also had more weight, less power (thanks to

carb changes to control emissions). And it somehow looked more sober than the K models it replaced. The revamped (and short-lived) CJ250 appeared in 1976, but it would give way the following year to the allnew, three-valve CB250T.

If you’re tempted by a CB250K (which seem to be more desirable than the G5 and CJ variants), the paradox is this. Though Honda shifted thousands of them in the UK and Europe (the 250 wasn’t available in America, though the

CB350 sold by the truckload), relatively few have survived intact and they are getting hard to find. Most were ridden into the ground by penniless young bloods or, slightly later in their life, by scrooge-like commuters eking out the last maintenance-free miles from what was by then just a cheap and cheerful hack.

The good news (for some of the same reasons) is that spares are fairly plentiful – and most are interchangeable with the

corresponding CB350 model. The specialist suppliers listed below all have pretty good stocks of mechanical and cycle parts, and there’s tons of decent stuff on ebay. Original exhausts and seats are scarce (aftermarket silencers are available), but you should find just about anything else you might need. Probably, a K4 would be about the best bet. All the mechanical mods should have been done and you’ll still get the classic looks – and a bit more performance than the lardy G5. Go for a complete machine and consider whether rare items like original exhausts are on your must-have list before you take the plunge. Find a good one for less than £3000 and you’ve probably done OK. Find a good one for £2000 and you could be laughing.

Seek and ye shall find. Hopefully.

THE RIDE

First things first. For a 250 – especially a four-stroke 250 from the tail-end of the ’60s – Honda’s first CB250 is a quick machine. If it’s in good mechanical order, it’ll nudge 90mph on the road. And when Motorcycle Mechanics tested one in the less mechanically sympathetic world of new model testing at Brands Hatch in summer 1968, they managed to squeeze 94mph out of it. But even without resorting to the flat-on-the-tank antics their tester doubtless got up to, the CB250K is still pretty lively for a 250. In fact, there weren’t many 350s – or even 500s – that were appreciably faster.

That speed comes at a cost, though. You need to get the Honda’s ohc engine spinning above 7000rpm to get the full benefit of the (optimistically claimed) 30bhp.

There’s more than a touch of parallel-twin vibration between about 5000 and the magic 7000rpm, but hey, there’s no gain without at least a little pain. If you don’t mind keeping the revs up, the CB250K is certainly capable of providing a little excitement. Gradients and pillion passengers knock the edge off top-end performance, though, and you’ll need to make the most of the fivespeed gearbox to maintain reasonable progress. It’s not a bad ’box, but after around half a century of use and abuse, some can be a bit noisy and notchy.

As with many bikes, later models are not quite as lively. Revisions to cams and carbs to meet tighter emissions regulations robbed a little pep after the K2, while the 1974 G5 is appreciably slower (and heavier) than the K-series bikes. Handling is as good as most bikes of its era and, with sticky modern tyres fitted, you’ll be able to appreciate the CB250K’S sprightly performance. You might want to upgrade the rear shocks – the originals were marginally damped at best. The forks can feel a bit soggy on well-used examples, too, but aftermarket replacement springs should help improve things.

There’s not a lot to choose between the K-series tls front brake and the single disc of the G5 (and CJ). But the rear drum is perfectly adequate and, unless you’re riding harder than you really ought to be on a ’60s/’70s 250, you shouldn’t frighten yourself too much.

You might just be surprised at how much fun you can have on a ‘mere’ 250. A K-series machine is probably more desirable than a G5 or CJ, but even the later models can be fun on the right roads. You get civility, too. Electric start and indicators help to make living with a CB250 on today’s roads easy.

That’s what the CB250 is all about. It’s easy to live with, easy to maintain and easy to ride. Find the right bike and it might just be (relatively) easy to afford, too.

‘THERE WEREN’T MANY 350S OR EVEN 500S THAT WERE APPRECIABLY FASTER’