STRAIGHT FOUR 750

Not Very Naughty, But All Quite Nice
Tests by Brecon Quaddy

(from UK “Bike” magazine December 1984 three-way comparison, CBX750 vs Kawasaki GPz750 vs Suzuki GSX 750 EF)

Honda CBX 750

What d’you call a bike which doesn’t vibrate, emit any noise worth complaining about, which handles and steers a treat, looks pretty, and barely needs cleaning let alone servicing?

God knows what possessed Honda to let someone persuade them that innovation alone is the key to success. They know who he is. I suggest they retire him immediately to a comfy chair with a supply of Mantovani LPs and Sanatogen. The CBX750, hailed by Honda as the answer for those riders who prefer the ‘classic’ Honda big bike engine is the most innocuous, forgettable roadster anyone’s produced this year.

The only exciting event in the test period was due to the actions not of the CBX but of Her Majesty’s laws on leave from the Yorkshire front. I was proceding southwards at XYZmph, thinking of little except the nervelessness of the experience thanks to Honda’s characterlessness, when a large white Rover appeared in the mirrors, complete with large blue flashing lights.

Alas for the instruments – if it hadn’t been for the messages relayed by the aircraft-style speedo in what we must now call the Honda’s cockpit I could’ve put my hand on heart and told the Plod I had no idea I was exceeding the legal limit. Okay, I was aware of the motor producing real power at last, so, in top gear on a motorcycle as peaky as this, I was therefore doing at least 100mph.

Don’t get the wrong idea. The CBX performs the most basic functions of a high performance motorcycle with aplomb. It’s fast to the tune of high 130mph pulls for the careless, and a good enough handler to make a scratcher out of the most inept and cautious rider you care to name.

But despite the reverential application of state of the art technology in pursuit of this game, the CBX signally fails to display the kind of verve that even its universal Japanese sub-Katana styling seems to promise. You can’t blame Honda for trying to cash in on the initial success of their V4s by cloning everything except the motor layout to produce the CBX. They just forgot one basic problem with clones; biologically speaking, they’re sexless. Their balls don’t work.

The CBX sounds promising at first. The motor, derived from a reliable series of fours hitherto seen only in the US, is less complicated than the watercooled vees with all the doubling up of cams, chains etc that a vee demands. Servicing access is better, not that a motor with self-adjusting valve lash plungers, hydraulinc clutch, brushless alternator and transistorised ignition should require much maintenance anyway.

It’s light by 1984 standards, at 481lb dry, powerful, with claimed 92 bhp at the crank and an honest 80-odd at the rear wheel giving nigh on 140mph in MCN top speed test conditions and sub-11 second standing quarter potential. Although the CBX looks and feels tall (seat height is over 31in), it’s narrow and nicely balanced with the motor slung low in the frame, taking advantage of the slimness of the cases and shallow sump (the latter made possible by using part of the frame as an oil reservoir.

The frame itself would only disappoint riders who don’t believe anything not made from silver painted square section tubing is good enough. The Honda’s round tubing frame is fairly simple and immensely strong: the reason the CBX looks tall is that space has been left to remove everything from cambox covers to pistons without taking the motor from the frame.

Suspension is all conventional Honda: the 39mm diameter forks are air assisted, and have an alloy brace to transmit the effects of TRAC anti dive adjustment and three-way rebound damping settings from the leg with the adjusters to the one without. At the back is an air assisted single shock with Pro Link rising rate, square section swinging arm and 18in ComStar wheel.

Apart from the hydraulic tappets, the one other unique feature of the CBX is its paired halogen headlamps which at last put a motorcycle on par with yer average car at night in terms of light intensity, if not spread.

Reports from the high altitude launch in South Africa obviously exaggerated the CBX’s peakiness since they suggested a big, fat nothing happening over most of the revband. Fact is, the crisp, quick responses of the four 34mm CV carbs disguise the paucity of power and torque through the midrange so the Honda pulls cleanly from all throttle openings.

Its six-speed gearbox is no gimmick, though, in traffic the light clutch action and slick gearchange are welcome attributes since you need to maintain a constant left foot shuffle to match ratios to what little poke there is below 7500rpm. On open roads it’s not so much of a hassle because the tacho needle whips rapidly round its dial and the closely spaced ratios allow you keep the motor boiling happily above 8000rpm.

Unfortunately, this two-stroke-like delivery isn’t matched by the bike’s character. Mechanical noise is barely audible, and the silencers strangle the exhaust note completely. The CBX gets on its cams at last not with a bang but a whimper, which is most disappointing. In all it’s like drinking a glass of water – no matter how fast you pour it down, it never tastes of anything.

The saving grace of the CBX must be its handling. The steering is light, precise and quick but not as nervous as many other 16in front wheel set ups. The whole plot seems to shed pounds once its moving, and despite the high riding position, it changes line or flip flops through esses with no inordinate effort required from its rider. Tyres – Japanese Dunlops of a more recent design than their counterparts on the Kawasaki – are among the best I’ve ever ridden on, giving superb grip, never affecting steering adversely, and refusing to white line or track along grooves or ridges.

But the brakes, standard Honda side by side twin piston calipers front and rear dolled up to look like race tackle, still fade worryingly after repeated crash stops, although it was only at the test track that the problem became acute.

Otherwise, they’re powerful and predictable needing only a slight squeeze on the lever at most times. Suspension, too, is ace so far as roadholding is concerned but until someone comes with an air assisted system that’s noticeably better than less fiddly, mechanically adjusted jobs then I refuse to be bothered with minipumps. On any comfortable pressure for solo riding, adding a passenger meant getting out the air pump unless I didn’t mind an over-compressed and soggy rear end. Insert Indian restaurant joke here.

For the rest, the Honda is pretty much Standard Jap. The usual designer switchgear is quickly learned, and Big H have extended the debt to Yamaha by nabbing the spring-loaded, push in to cancel indicator switch idea, unfortunately without the self cancel. The lights are good, although not twice as good, which is what you’d expect a twin headlighter to be. There’s a good grabrail, although since the CBX is supposed to be aggressive etc, the pillion portion of the seat is less than generously sized.

Comfort is a subjective quality but the CBX gives nothing away to the Suzuki while having a kinder riding position and gentler seat than the Kawa.

At the test track, the CBX joined our parade of Hondas which went home by truck, since its clutch went like all the rest before it could manage a run up the quarter mile. All sorts of things could be blamed, from R Brown’s youthful enthusiasm for butchery to our half mile top speeds which call for a fairly determined launch but it’s worth noting that, unlike US Nighthawks, the CBX has Honda’s limited slip sprag clutch device intended to prevent the rear wheel locking during downswaps.

Fitting the sprag assembly meant waving bye bye to two clutch plates, so the more powerful CBX has a less beefy clutch than originally intended.

Honda’s contribution to taking the nasties out of motorcycling can be applauded since it has produced bikes which are excellent fodder for people seeking nice, easy to live with machines like C50s, CB250N Superdreams and CX650s (especially the Silver Wings) but applying the same precepts to sports bikes only creates expensive and insipid bores. If only the CBX had a little bite… As it is, the few I’ve seen on the roads were mostly ridden by chaps over 40. This is one for the Sanatogen Generation.

Performance

Top speed in 1/2 mile prone……117.8mph
Top speed in 1/2 mile upright….117mph
Best one way…………………122.5mph
Standing 1/4 mile…………….N/A
1/4 mile roll on from 50mph……12.61sec/87mph
Top gear…………………….13.67mph/1000rpm
Fuel consumption
Overall……………………..6.7 litres/100km (41mpg)
Ridden hard………………….7.4 litres/100km (38mpg)
Speedo accuracy
At indicated 30mph……………30mph
At indicated 50mph……………49mph
At indicated 70mph……………68mph

Dyno results (performed on a Bosch LPS 002 at Motad Ltd) for the three bikes:
Suzuki GSX750 84bhp 8700rpm Kawasaki GPz750 81bhp 9500rpm
Honda CBX750 79bhp @ 9250rpm

Mr_T’s comments…

The mag then shows a dyno graph with the three bikes on it. Here are some approximate figures from the graph:

Suzuki 74hp@8200
Kawasaki 70hp@8500
Honda 68hp@8000

which, when you compare them to the stated figures, are a load of bollocks like some of the things they said about our favourite bike. Considering that the “Mechanics” test was done in June and the “Bike” comparison was done in December, “Bike” must have tested the most abused CBX in the entire Honda test fleet.

Viking’s comments…

I guess if you had a name like ‘Brecon Quaddy’, you’d be angry at the world, too.