HONDA CB750A HONDAMATIC
Twist’n’Go scooters are well known. Automatic cars are even better known. Frank Westworth was entirely unfamiliar with the CB750A Hondamatic, until now…
Twist’n’Go scooters are well known. Automatic cars are even better known. Frank Westworth was entirely unfamiliar with the CB750A Hondamatic, until now…
Honesty is the best policy. Possibly. I was staring at an online pic of a vaguely strange Honda. Do not laugh – several Hondas look vaguely strange to someone who knows almost nothing about Hondas, which would include me. However, I am familiar with sohc CB750 fours, because I ran one for a couple of years in the mid-1980s. Mine was a 1976 CB750 K6, bought cheaply because it sounded like no Honda should ever sound and the owner was convinced that the ghastly misrunning, clattering and misfiring was because the camchain tensioner had failed and the engine was
eating itself. My mate Bill, who ran a GPz750 Kawasaki so plainly knew all about Hondas, had already viewed the bike and had nodded and winked and said to me a magic word: ‘carbs’ – and he was not discussing diet.
Of course I offered a paltry sum, sensing a bargain. Of course the vendor accepted it, sensing a fool.
Happily, my mate Bill, despite a curious taste in Kawasakis, was head of maintenance at the company which employed us both and his diagnosis was entirely correct. His view, possibly based on grim experience with his Kawasaki, was that the wonderfully gurgly matt black 4-1 Piper exhaust was playing utter havoc with the four carbs on the Four. He was right. He could also tune the carbs to match the eccentric characteristics of the exhaust. He did that. It pays to have mates.
The Honda did exactly what it should have done. I liked it. In a remote sort of way. It was reliable. In a dull sort of way… apart from the front brake, which would reliably seize up every winter, a more than minor irritation, given that the bike was the daily driver and took me to the factory where I did my worst to earn a crust. I sold it to a policeman who paid for it with overtime earned during the
famous miners’ strike and bought a T150V Trident, which entirely fixed the dull reliability issue. And while I fixed the Triumph, a permanent and continuous process, I rode to work and everywhere else on a 1966 AJS 31. Wins all round.
However, the Honda at which I gazed more recently claimed to contain an automatic gearbox. At this point I should of course point out that there was nothing even faintly wrong with the gearbox on my own CB750. It was excellent, in fact. The clutch was light and progressive, the gears were well spaced and engaged with a precision lost on, for example, several Mk3 Norton Commandos built after 1976 or so. However, back in the mists of antiquity (the early 1990s, to be less inaccurate) I had been tootling around on a loaned Guzzi California, which I liked, and commented to the then importers that I’d love a go on a Convert, which I’d read about and seen about the place occasionally, but never ridden. ‘I’ll get back to you,’ was the reply. They didn’t, of course. But I was intrigued. As indeed I was by the Hondamatic – which I’d never even seen in the tin. And then the indefatigable Chris at Venture Classics revealed that he’d bought one… Which is where we came in.
First glances can waste a lot of time. When I first saw the Honda I thought, inevitably, ‘Oh it’s just another Honda Four’. Except, it’s not. Or rather, it is. Look closely and observe the oddly strange engine, the unfamiliar exhausts, the tank which is more like that on a GoldWing than a CB750. And of course there’s no clutch lever. And it has no tacho.
You may not already know this, so be prepared for a shock. Our main winter riding machine has three wheels, two of them at the front. It also boasts an automatic clutch, which is an entirely wonderful device which makes stopstart traffic grinding less of a strain on fingers which are increasingly arthritic, weak and painful. Unlike the Honda, the tricycle still has a gearbox, shifting its ratios when encouraged by a paddle device on the left-hand handlebar. I really enjoy operating this neat system, and was increasingly
interested in the Honda’s fuller auto.
The engine starts like all elderly Honda Fours – gradually. And as I learned while owning one, it’s a good idea to let it warm through a little before discovering the delights of mastering the four… two… four… three cylinders arguing among themselves until they reach an agreement and run reliably on all four. It takes longer to describe than to happen, but by the time I’d watched Chris put air in tyres and gaze sadly at the rainy skies it was running smoothly and quietly, as all good Hondas should. I rode it up and down the drive, then togged up and was on my way. With a little trepidation. An automatic motorcycle? Who’d even consider such an obvious insanity?
The engine looks like any old CB750, right? OK, it’s not. Look more closely. The substitution of the torque converter for the standard transmission required rather more than a simple set of new crankcase castings. The CB750 is dry sump, with an oil tank under the seat. The CB750A is a wet sump design, using the engine’s fine finnery to cool the oil, which is also used by the autobox and gets very hot and possibly bothered. Lots of the engine is different, not least its power output, which was quoted in the press of the day at a less-than lofty 39bhp at the rear wheel – quite a lot less than the standard foot-shifter. And as you might imagine, the considerably different state of tune produces a remarkably pleasant engine, an engine which is perfectly matched to the unusual transmission. No surprises there; Honda are excellent engineers.
The pod where the tacho normally resides is given over to a panel of flashing lights. And a fuel gauge. It’s hard to get excited about a fuel gauge, but the flashing lights are a different matter. The most important are the three big ones, which show what condition the autobox is in – neutral, low or high, and in this case ‘high’ is rather mysteriously represented by a handsome star. This is only puzzling if you’re a tad anorak and waste hours looking at pics of other versions of the bike you’re supposed to be writing knowledgeably about. Those wasted hours reveal that otherwise identical machines offered in different markets have either ‘D’ or ‘2’ instead of the star. Exciting, huh? And there’s more: the test victim’s speedo reads only up to around the ton (it’s a kph device, too) whereas those for other markets ran up to maybe 120 or so. However, on the feature machine where the numbers on the speedo end is … a star. What does it all mean?
Rigorous and selfless research – a personal speciality, as you know – reveals that like a 4-wheel auto there are two gears. You knew that already because I told you already. However, all the auto cars I’ve driven would all be perfectly happy driven all day with the lever left in ‘D’ for ‘Drive’. In fact I can only remember using ‘L’ for ‘Low’ once on a Range Rover in truly awesomely bad ice and snow. The best advice I could find about the Honda’s box is that ‘1’ is great from stationary to around 60mph, while after that the engine
would surely appreciate the higher gear.
Gentle reader, I have a confession. I only rode it in ‘*’ or ‘D’ as it’s called in other markets. In this case the ‘D’ stood for ‘Delightful’, which in fact – and surprisingly – it was. Maybe I should borrow it again just to see whether it transforms from a soft lazy sofa bike into a roadrending raptor when both gears are used. Or … not.
There are a few lessons to learn, as you might expect. The engine can only be started when in neutral. And in typically clever Honda thinking, kicking out the sidestand also engages neutral. Neat. The next thing to learn is that there is a parking brake. When the engine isn’t running it’s not connected to the rear wheel, so when parking on a slope the bike could roll off the sidestand – not that any of us has ever suffered this. Oh no. Except on borrowed Ducatis and at least one of our own BMWs, but we’ll not mention that. There should be a pic somewhere nearby which shows a little double button below the tank on the left – the sidestand side. It’s quite logical. Operate the button to lock the rear brake and release it before riding off. And in case of possible accident those clever Honda engineers arranged things so that the brake stays applied after the button’s been released until the brake pedal gets a prod from the right foot. You only forget about this once.
As is so often the way, describing how things work takes longer than operating the thing itself. So this is how it rides. More tech stuff in a moment. You sit on the bike and start the engine, and let it warm a little.
You reach for the clutch, which in this case we have not got. You look sheepishly at the owner, who sniggers quietly. Then you tap the little lever into gear – in my own case up into top. I’d expected the revs to drop, but they don’t, in fact they rise a little due to more techno-wizardry from Big H. It slots into gear quietly, too. Unlike on the conventional Fours, neutral is at the bottom, L is above it and D (or * in this case) is above that.
Next, you wonder – if you’re familiar with the dark art of stalling an unfamiliar machine in front of its delighted owner – whether to raise the revs quickly to avoid the fluffery some Honda Fours of that type can suffer from. On the other hand, this is an auto; raising the revs without gripping the front brake could result in a very short, very fast flight into a flowerbed. So just open the throttle as you would if you were feeding in the clutch. Which you’re not, but you know…
No drama at all. The bike simply pulls away. No fuss at all. Close the throttle and it slows down. Unlike the automatic clutch on our own tricycle, the torque converter simply fades from your consciousness as the revs fall away. There’s no step at which the connection between engine and rear wheel is abruptly lost. Tremendously civilised stuff, this. Fascinating, in fact. No, really.
Conventional wisdom has it that these bikes have no clutch – in fact they have two. Smart stuff abounds here. The gear lever does not in fact engage a gear, instead it operates a hydraulic valve, which in turn directs oil to two hydraulic clutches: one each on the input shaft (low gear) and the output shaft (high gear). The two clutches mesh the gear pairs required for either low or high ratios, using hydraulic pressure rather than springs to apply pressure to the plates. And the torque converter itself came from another Honda entirely – the N600, which is a car…
There’s hidden cleverness to avoid the stall concern – as I discovered after riding the bike, of course. The four carbs are smaller (they’re 24mm Keihins) than the set fitted to the plain conventional CB750, and one of them is fitted with an accelerator pump to avoid the step between tickover and an opening throttle. I didn’t notice it. But I do remember the off
fluffing on
my own CB750.
Once on the move it all becomes quite familiar quite quickly. The Hondamatic doesn’t feel slow, despite the lower power than the ordinary model, and the flexibility of the engine is exploited perfectly by the torque converter, which slips merrily and entirely unobtrusively while it takes up the drive until the road speed catches up to the engine speed which is what you set with the throttle. It’s … fun. Very smooth fun, too, and a further surprise to this former Honda owner was that there’s no transmission snatch. And no essential gear changing, of course. You open the throttle gently; it accelerates smoothly until it reaches the speed dictated by the twistgrip. Snap that throttle open, the revs rise sharpish and you accelerate sharpish. Try it! It’s actually brilliant. And I would have hated it when I was a feisty fellow in my 20s or 30s because I wanted to decide myself when I changed gear, both up and down, because I was Mike The Bike on his mighty Honda and us Mikes need to operate the gears to get the very best out of our fearsome Japanese multis! Or not…
As you can see, the bars are big and wide. The seat is plush and deep and the rests are in a sensible place. The Hondamatic is considerably comfortable, which is another reason I liked it – liked it a lot in fact. Chris had pumped up the tyres, and the roads were very wet (this is a familiar pattern) so I can confirm that it was confident and stable, but not that it would crank over until the exhaust decked. It’s not that kind of bike … and I’m not that kind of rider any more!
So this is a great tourer. The suspension is of its day, a little soggy and somehow firm at the same time, while the rear brake is perfectly fine. This machine has an sls drum at the back, but later machines gained a disc. The front brake is not great, as these things rarely are. I’ve never liked them, so apologies for sounding less than enamoured.
That brake? It’s a cheap device, with hydraulic fluid pushing only the outside pad into contact with the single disc. The calliper is mounted on a pivoting arm, which in theory, based on the action and reaction notion, pulls the inner pad into contact with the other side of the disc with equal force to the pad which receives the hydraulic shove. In practice the pivot seizes up. Not in this case, judging by the feel and the decent level of bite, but that has never stopped me disliking them!
Handling is just like the K6 Four, and it wheels around at low speed very easily indeed, considering its bulk. Although I didn’t ride in busy traffic, I’d assume it would be very relaxed about it, and remembering to use the lower ratio would probably help…
Honda’s investment in their Hondamatics must have been huge. Although the engine looks much like a conventional pedal shifter, it’s not. Ignoring relatively inexpensive items like the smaller carbs and lower compression (8.6 : 1) pistons to match the softer cam design, the drive from the engine is different too, which must have been truly costly. Whereas the foot-shifter uses a pair of short roller chains (with no tensioners) to transmit power from the crank to the gearbox, the auto uses a single Morse Hy-Vo chain. This supplies power to an intermediate shaft, which is in turn geared to the gearbox mainshaft. There might be a pic or two nearby to show what it looks like. I’m sure it’s all very simple, really, at least to an engineer.
However, appealing though it sounds – and indeed was – the Hondamatic failed to set the market alight, in much the same way as the Convert did not take the Guzzi world by storm. The Hondamatic was introduced for the 1976 model year, received cosmetic changes for 1977 and … Comstar wheels for 1978, after which it faded away. The feature bike dates from the 1977 model year, and is remarkably standard, having gained a fourinto-two exhaust to replace the earlier fourinto-one, as well as the high bars and a deep seat. Honda were not after the sporting rider, plainly. Which begs a question: why did they choose the 750 four and a 400 twin for their autobikes? Surely the shaft-driven GoldWing and SilverWing machines would have been better? We’ll never know, sadly. And it is sad, because auto Hondas are with us again in 2019, of course – just go and check out their 2019 listings. Except… the most interesting autos aren’t offered in the UK. It was ever thus…