It was probably unfortunate that at the same time I was riding a ‘71 CB750 four, I was also burning rubber on a nearly new CBR600. The 750 was purchased in a hurry for a not unreasonable five hundred notes after I'd managed to completely wreck my Yam FJ1100 in a manner I have absolutely no intention of revealing here.
With two owners and 45000 miles on the clock, the bike looked tatty but still ran rather well. It was just that the CBR was so much lighter and faster and better handling and safer, that every time I had to swap bikes, the amount of muscle and concentration needed to lurch the 750 through traffic or bum along at fairly mediocre speeds (read 90mph) was so much more that I kept getting caught out by road and traffic constraints.
While it's no doubt unfair to compare a 15 year old bike with the latest (and probably best) four to be churned out by Jap Inc., as some vendors are demanding more than two grand for early and original examples, it's not quite so far fetched as Honda addicts might like to think.
The CB750 first hit the showrooms in 1969 and was instantly recognized as the first Superbike. I would mention the Trident here, but the Editor informs me that my last diatribe on that bike so upset Trident owners that many of them have vowed never to buy the UMG again; so I'll just limit myself to saying that the Trident never was and never will be a Superbike. No, what Honda achieved was to produce the first bike to knock out decent power without heeding constant care and attention. It didn't vibrate, it didn't leak oil, it didn't shed engine components and it didn't even cost much more than British twins.
It also didn't handle. The bike I was riding had some fairly new Koni shocks, taper steering head bearings, heftier fork springs, strengthened swinging arm and flat bars, but the duplex steel frame was so inadequate that even these improvements couldn't stop 500lbs of top heavy metalwork doing its own thing more often than it did what I wanted it do.
OK, so if you run along at 70mph on flat roads the thing is just fine and it can even be leant over a little without wobbling. But try flicking it through a series of S bends and the poor geometry and weight distribution will have the damn thing careering off to play car wrecking with oncoming traffic, or bush demolishing with outraged farmer's hedgerow. Take a firm grip on the bars, wrench in on the survival line, the stand digs in and the bike tries to grove like a ballerina on half a pound of acid. It got so bad at times that I actually had to cut down my speed to more moderate levels. Trying to cruise above 90mph on motorways induced a mild weave (if you can call needing a yard's width of tarmac mild).
Overtaking large lorries, the resulting blast of wind meant all control was lost for a few seconds and the bike appeared turned on by the central crash barrier. Things became really worrying when I had to brake hard and simultaneously change lane to avoid some blind imbecile in a Sierra who apparently wasn't concerned about receiving a 100mph dent in the back of his car. Naturally, I screwed the Honda out to its max whack of an indicated 133mph (really a true 125mph), gave him a couple of fingers as I took him on the inside, then cut across him back into the fast lane. I was tempted to dump on the brakes and smack him in the mouth when he had the audacity to bleep his horn at me, but had become rather too preoccupied with the bucking and bouncing Honda to bother with such niceties.
Ahem, devoted fans of early Honda fours had better either skip this paragraph or go get a medical check up before they read it. Having ridden many old Jap and English bikes, I can safely state that at the very high speeds these old fours are quite capable of, the CB750 turns into the nastiest, most unpredictable and downright devious bike I've ever had the, er, pleasure of riding. Regular readers may have perceived that I have a certain addiction for speed and that I tend to make the max use of an engine's power, but every time I tried to utilise the Honda's capability, I came perilously close to a dose of tarmac rash. The Editor, who has apparently developed an endless list of reasons why he should avoid riding dubious motorcycles and spend his time lounging in Bangkok, merely laughed when I suggested he have a go; laughed and added that many people found these kind of characteristics a challenge and kind of character building...
Switching between CBR and CB750 had the same kind of shock as switching between asprin and heroin. The high speed world of the CB750 was one of a tremendous high on one of the rare times when everything went well and paranoia and delusion for the rest of the time. Part of the problem came from the remoteness of the chassis. The kind of removal from tarmac reality that a Suzi four usually suffers, but manages to overcome because of its useful stability and neutral handling. On the Honda this remoteness combines with unpredictability and plain old bad design.
After about a month's practice it's possible to become used to this kind of thing and avoid an early grave, but I had usually become used to the CBR600's brakes which were quite progressive and would have done cartwheels if I'd been. silly enough to apply the same kind of pressure as needed to stop the older four in the dry. Compared to the TLS drum on the equally heavy Trident, the single disc was rather wonderful, but this is rather like comparing a Voskhod with a CZ and hardly relevant in a journal of the UMG's stature.
The disc is fine if you don't ride the CB750 above 70mph, plausible if only used occasionally up to 80mph, but any faster speeds soon show up both a lack of power and too much fade as the caliper begins to overheat (after a hard run you could lay the bike on its side and fry an egg on the disc). If you want to use a CB750 properly go visit a breaker and swap the whole front end for something rather more modern.
I had the opportunity to ride a bike rigged out with Dresda forks, twin discs and box section swinging arm. It wasn't exactly a whole new world, but it was stable all the way up to the ton and the stickier tyres (Pirellis as opposed to Avons) made it feel several times safer in the wet. There was still a weave above a ton, that given some bumpy roads could still turn nasty but at least the build up wasn't quite so sudden and I had some idea when to back off.
The stock Honda has a typical period piece riding position that helped no-one except for osteopaths. The original and rare K0 model had huge ape hangers to cater for mentally retarded Yanks, the K1 had flatter (but still high) bars that had the kind of relationship with footrests placed six inches too far forward that would have given the Marquis De Sade a whole new vista of possibilities. If all that's lost you, I ride the Honda for a couple of hours at high speeds to be left with a sore bum, shoulders and thighs. Rear-sets of some sort are obligatory unless you just like running around town (go buy a C90 if that's your scene). Combine these with flat bars or clip-ons to give a marginal improvement in handling and a quantum leap in high speed comfort. Only problem is that in town the beast becomes awkward and heavy to shove around with any aplomb.
The clutch is quite light, but a little jerky. What sounds like an engine on the way out, is often a clutch on the way out. This rattles annoyingly even when in perfect condition, and needs attention after fifty grand or so. Like most jobs on the Honda, it's simple enough but don't blame me for the cost of new bits.
Primary drive is a hyvoid chain with no means of adjustment to compensate for wear. This is one of the few bad points of the Honda design - given that they were using gear primary drive ten years before it's hard to see why they saddled the Honda with such a poor design. That said, it doesn't actually wear very fast and some 100000 mile bikes are still on the original items. It does, however, promote transmission jerkiness in a driveline that from new was never A1. On my own bike I could feel the chain, clutch and box thrashing around every time I changed gear, whether in town or on faster roads. Every one of the new high-tech fours uses gear primary drive.
The crankshaft is a commendably tough five bearing unit, with alternator on one end and chain drive for the single camshaft in the centre. The tensioner is not automatic but it doesn't suffer from instant demise (anywhere from 40 to 60 thou) and even the chain can last for surprisingly long distances (one wonders where Honda designers went wrong on some of their later designs).
A single cam drives just two valves per pot though rockers with delightfully simple (or quaint if you prefer) screw and locknut adjusters. Just position the cam, slide in your feeler gauge and adjust - they can be neglected for as much as 4000 miles before any great damage occurs. Contact breakers are usually thrown away and replaced with Boyer electronic ignition in the search for better economy and less maintenance.
Another strange quirk of the CB750 engine is that it actually has a separate oil tank. While there's nothing really wrong with this, it just adds unnecessary complexity and weight for no return. Most other Hondas have wet sumps as does that most reliable range of the fours, the GS Suzukis. Change the oil every 1000 miles (or even less if you really use the power) and don't forget to change the oil filter occasionally. Failure to bother with oil changes will eventually write off the whole engine and is really the only way to destroy one of these engines quickly. A pint of oil lasts for about 350 miles and a gallon of petrol from 35 to 55 miles depending on the level of thrashing - I usually get 40mpg. Rear Roadrunners last around six thou and fronts go for ten grand.
After about six weeks ownership, I found a puddle of oil under the left side of the engine. The Editor immediately diagnosed a ruined clutch pushrod or gearbox shaft seal, which used to go quite often on his CB450, due to the proximity of the seals to all the crud picked up by the drive chain. He even offered to lend me his large hammer and small chisel that he claimed were the business for removing chewed up screws - and these were chewed up Allen bolts.
Much swearing, snapped screws and bruised and bloody fingers later, I had removed the cover, revealing a horrible sight. There was a huge hole in the crankcase with a few bits of what looked suspiciously like Araldite around its edges. Some time in the past, the chain had snapped and broken into the crank. Luckily the Ed had a supply of Araldite to hand it really is wonderful stuff, but do give the fast setting version a miss. I don't know how long this repair will last and it's a bit paranoia inducing to ride a bike fast with such a quick way of losing all its oil, but I don't fancy tearing the whole engine apart to have it properly alloy welded, and I hope there aren't any chunks of rogue Araldite circulating in the engine.
Chains, when they are not snapping, last around a mere 8000 miles. Taking a link or two out ain't recommended because by that stage it'll be so worn out it's almost certainly going to snap - rather more expensive than buying a new chain. The engine knocks out 67hp at eight grand, doesn't have a vicious power band and can't really compete with modern 550s. It especially shows its age above six grand when some quite fierce secondary vibes get through to the bars and footrests. Tingling fingers result after a whole days riding.
The earlier the bike, the faster and lighter it is. The final K model, the K7, was 20lbs heavier and nearly 10mph slower. True, it had better suspension and was more stable, but there were much better bikes available from other Jap manufacturers. The usual path of four into one exhaust, non-stock air filters and better suspension made the K1 or 2 that much more useful. There were big bore kits and high lift cams, and they didn't harm the engine reliability - it was just the poor chassis making them very frightening options.
Reliability of the engine is the bike's strongest point. Honda even spoilt that in the F1 version, when the same basic engine was installed in a new chassis. The tuned engine made it rather fast, but the power could take out the clutch, cam and primary chains. The F2 regained the reliability of the K series by detuning the engine and had much better handling than the older bikes. As this machine is unaffected by the nostalgia for the K series it's probably the best value in SOHC 750s.
The early K series has ease of maintenance, durability and a certain amount of style in its favour. It's the latter that will probably keep the value of the early bikes up quite high. These days, the relationship between how a used bike performs and how much it costs has been submerged under a mythology that holds style above all else. No matter that you will probably kill yourself if you try to ride the CB750 fast, it was the first Superbike and it looks the part. Just as the problems of many old British bikes have been forgotten, so some of the old Japs will gain new life under the title classic.
Johnny Malone