Saturday 14 July 2012

Honda CBX750


With a turn of the key, the 320hp engine growled into life without the aid of choke or accelerator. As I crunched it into gear I thought to myself, here we go again. Pulling out of the compound with a 40 foot trailer behind I was wondering how many times the everyday motorist was going to upset me today. What? 40 foot? Did I fail to mention that I'm a truck driver as well as a motorcyclist...there's a lot in common with truck driving and biking.

You have to be constantly aware that people will try to pass you on either side whether you are turning left, right or trying to go around a roundabout, and will drive out in front of you with a death wish.
At the end of the day I park up the trusty bread winner, pulled back the big polythene bag I use to keep off the worst of the weather; a smile comes over my face as the biker in me takes over. There it is, my pride and joy, a CBX750F.

Usually immaculately kept I like to think, but the morning's rainfall has left filth all over. Still, a good wash will soon see it off. To climb on and fire up the four cylinder, DOHC engine makes the pressures of the day disappear. No more being blown off by idiots, no more traffic jams.

On leaving the lorry park, I go straight on to a dual carriageway, whack it up to seventy(ish) and begin to feel very uninhibited, it's like a hunchback losing his hump. Stability on fast, open roads is always excellent with none of the weaves and wobbles that made earlier, SOHC models so, er, amusing. It doesn't take long to get home; I went the long way to avoid traffic lights and roundabouts. There are times I wish I lived further from work to give the excuse for a longer trip, the bike just gets warmed up and I'm home.

Normally, I spend about four hours a week just washing and polishing the bike, any maintenance takes extra. Not that there is much maintenance needed - hydraulic clutch, self adjusting tappets; no problem there, just so long as a good grade clean oil is running round them and not some sludge dragged from the local beaches. The carbs stay in balance for long periods of time, the ignition is electronic, so those frequent oil changes are all that's needed.

I even fitted a Scottoiler to the drive chain which reduced chain wear dramatically. Running to work and back every day, stopping and starting, made it necessary to adjust the chain every three weeks before fitting the oiler, now I just check the oil in the reservoir every 200 miles and adjust the chain every 2000 miles. The money saved from not buying expensive and filthy aerosols plus the longer chain and sprocket life soon pay back the money spent on the oiler.

I don't only use the bike for work. Last year I went to the NEC bike show. Trouble free riding until I was coming back and about ten miles from home (Teeside) had a 90mph puncture in the back tyre. The first time I've had one on the move and I wondered what the hell it was, the back end going ape-shit on me. Being dark I thought at first I might just have run over one of those furry things with big ears, they do like to top themselves on the Queen's highway.

I slowed down to about fifty as my mate, Geoff on his BMW 1000, shot past, the bike stabilized and I thought the problem had cleared up. I opened up the throttle again, I didn't even make 55mph, shot the brakes on and pulled off the road. It took Geoff 15 minutes to realise I had gone. Fortunately, we were able to get a van and get the bike home without too much fuss. It turned out the moron who had owned the bike before had put a tube into a tubeless tyre and it disintegrated on me - I'm told that this is not a recommended practice. Just goes to show how good was the stability, on a lesser bike I would probably have been chucked off.

Kitted out in Metzelers front and rear, I find that I can throw the bike well over into a bend in dry weather and have plenty of confidence that the tyres will not slip. In the wet it's a different matter, with the weather being dry for days when we get a small amount of rainfall we get roads too greasy for any heroics. General running in the wet means keeping a rein on the throttle wrist and not leaning over at extravagant angles. The double discs don't suffer wet weather delay but there is a tad too much power for nerve free braking. At least the calipers haven't seized up nor the discs worn away.

On one long run, down to Uxbridge, when we got caught up in an endless traffic jam into London, my wife complained bitterly about pillion comfort and refused to entertain the idea of any long runs on the bike ever again. She said it wasn't natural to have her legs apart for so long, a bit like a marathon visit to the gynaecologist. I enjoyed myself, I get a kick out of seeing other people in traffic jams instead of me in the truck.

We averaged about 35mpg on that trip, which I was quite happy with as the bike was well loaded up. The best fuel consumption is around 55mpg, although it's much more common to average 40 to 45mpg. Yes, not better than some small cars but a hell of a lot more fun. I have a Rickman box on the back, ugly and spoils the lines of the CBX, but it is very useful. As well as this we had a rucksack filled with clothes and another bag strapped to the tank. The bike still handled well with the additional weight.

Scarborough is just an hour away from where I live, so I go to the road races there which are held three times a year (pity so few, as it's all good stuff). Coming home is always quicker than getting there, good fun for me but the pillion (the brother- in-law) tends to get a bit worried from time to time. I often fancy myself as a budding Carl Foggarty, and knowing the roads, thanks to my truck driving, gives me an edge over my BMW owning mate.

One bend in particular that I like comes back on itself and I can get the Honda really banked over. Geoff was following me on this occasion and later admitted that he thought he was going to disappear up his own arsehole. The brother-in-law claimed that had the bike gone over he would not have fallen off as his backside was gripping the seat so tightly.

The bike has done just short of 30,000 miles and it's over four years old. It still goes very well, as well as looking almost as good as new. Engines should run to at least 50,000 miles before needing any major work (given decent oil changes), the clutch and exhaust valves are the first signs of imminent engine demise (the former slips and the latter permits copious quantities of blue smoke to escape the exhausts on the overrun).

Another sign of wear are the silencers and pipes, a one piece set which is bloody annoying as the baffles are just about spent and to replace them with genuine Honda parts will cost between £350 and £400. I could get a replacement 4-1 but I would like to keep the bike in standard trim. I may end up making my own baffles once the bike gets too noisy.

One pillion I gave a lift to was so bad he frightened the life out of me the first time he was on board. Every corner he was trying to pull the bike back upright or, failing that, climbing off the other side. We had a shouting match at the end of the ride because he wouldn't do what I told him and I wouldn't stop leaning the bike over..... pillions are okay now and again, but I think I'm basically a selfish rider wanting the bike to myself.

I've had the CBX for just over a year now and although I have enjoyed owning it, early next year I would like to change it for something else. Trouble is, I don't know what yet. My brother has a VFR750 Honda, very nice and a fast bike but a bit too sporting for me. The closest I've come to finding a bike that's as easy and comfortable to ride is a FJ1200 Yamaha.

Alan Brown

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Within a week of buying a 25000 mile Honda CBX750 I was well into a Grand Continental tour that involved Germany, Belgium, France, Italy, Spain and Portugal. I was averaging 500 miles a day for a whole month. By the time I was back in the UK the mileometer read nearly 41000 miles. It was an interesting way to test the qualities of the Honda.

The CBX750 has a quite advanced aircooled four cylinder engine. DOHCs with four valves per cylinder, with maintenance free hydraulic adjusters, helped knock out a claimed 90 horses. A record for a 750 Honda four of this type and way ahead of the original CB750 four of 1969 which managed just 67 horses. Not much progress had been made on the mass front, both machines weighing in at a hefty 480lbs, though to be fair to the CBX some later CB750s broke through the 500lb barrier.

The frame, geometry and weight distribution are all way ahead of the older four. Where the original CB would wobble and weave given the merest encouragement, my first impressions of the CBX were of a solidly together machine, that would shoot through traffic at a terrific pace and hold a steady 90mph with all the ease of a GL1500.

Three things tested the limits of handling during the tour. First there was myself, passenger and excessive luggage. That added up to about 450lbs of ill-distributed mass which had as much an effect on the suspension as it did weight distribution. Most noticeable was the way it would take to falling into corners, making a lunatic lunge for the tarmac. At times it felt just like a slug of a Plastic Maggot I used to own.

The suspension, normally pretty good solo, was so compressed that trundling around corners would have the stands, pegs and exhaust trying to either dig holes out of the ground or throw nigh on a 1000lbs of machine, people and luggage down the road. Anyone who's owned a Z1 will know the necessary technique to overcome this. Point and squirt was the name of the game, though it was dead easy to tie the chassis up in knots if you weren't paying attention.

The second problem with the handling came from my choice of tyres. Both Metz's and Avons suited the bike exceedingly well, chosing slightly fatter sizes than stock giving a glued to the road feel. Unfortunately, for the kind of mileage I was doing their wear of less than 5000 miles a set was totally unacceptable. Which was how I ended up with a cheap set of Far Eastern tyres that were vile in the wet, but that wasn't a great problem on the tour as I only saw rain for half an hour on one day in Spain. In the dry, grip was acceptable, weaves tolerable and their life over 20,000 miles!

I did find, on one section of Italian back road, where the surface turned to gravel, the tyres had a vicious breakaway point, lurching away towards oblivion without the slightest warning. One moment I was upright at 35mph, the next thing I knew was that bike and I had parted company. The luggage absorbed the worst of the gravel rash and I rolled with my momentum, saying thanks to the old man who'd insisted on providing me with full leathers fitted with built in body armour. I looked a right prat whenever I got off the bike but that was a small price to pay for avoiding a hospital visit. Luckily, my pillion was thrown into a relatively soft ditch and only suffered minor bruising.

I had neither medical insurance, vehicle recovery nor a bail bond, trusting my progress to the gods. To be honest, I would've liked all three but I'd spent most of my money on the bike and had just enough spare change to keep up with the consumable demise and petrol costs. Oil changes were extended to 5000 miles, the carbs never touched and petrol disappeared at a reasonable 50mpg.

The third handling problem came from riding on German autobahns. The Krauts are an orderly bunch, not even perturbed when my pillion gave them Nazi salutes to overcome the boredom, but they don't half know how to drive fast. The CBX was a tireless 100mph cruiser, even quite comfortable with the protection from the frame mounted half fairing, but I was forced to push things to their limits with 125 to 130mph deemed necessary to keep up with the pace.

Solo, it'd probably have handled even that excess with reasonable proficiency but with all the mass it was a pretty poor sight, waltzing around in its lane so delinquently that the Kraut cagers were bashing away on their horns, in a fit of pure horror at this attack on their orderly nation. Fuel was only 30mpg, which with the state of my finances eventually forced me to knock back to the slow lane pace of just 100mph, which turned in 42mpg and was accompanied by the mildest of weaves on the relatively smooth autobahn.

Comfort was much better for the rider than the pillion, who was assaulted by a flurry of secondary vibes and shook about by the way the back wheel could let loose. I was quite happy to do 150 miles before pulling over for a fuel stop. It was only after 400 miles in a day that I was a bit saddle sore, a lot of shuffling about thereafter necessary and stops every 50 miles for a quick stagger. The most I did in a day was 850 miles but I had to take the next day off to recover, so it was a bit counter productive to do much more than 500 miles.

The only real hassle I had in that minor adventure was the ongoing disintegration of the OE 4-2 exhaust. It proved mildly amusing to consult our dictionaries whilst trying to make various foreigners comprehend that we wanted the holes in the silencers welded up. Luckily, most of the work was done in Spain and Italy where labour costs were ridiculously cheap and once the language barrier was overcome the people very friendly.

The CBX has great power characteristics but they were easily ruined by holes in the silencers, which added an excess of flat spots and stutters to the power band. With a decent exhaust, it'd run fine up to 6500rpm, then charge hard right into the red. It would toddle along at 30mph in top even with all the excess mass, slowly gaining momentum with a gentle throttle hand. Alternatively, solo with hard use of the gears and throttle, it'd growl along the road at a fair old clip, having sufficient urge to wrench my body, spin the back wheel and if I was feeling really nasty even do a wheelie, though it felt as precarious as riding a unicycle along the high-wire! The gearbox was good for some swift changes if a little care was taken in the first to second shift, though it was often just as easy to take off in second, no clutch slip needed and no transmission judder experienced.

Once the tour was over, we settled into the daily rush to work, as the weather turned nasty as only an English winter can. It only took a week for the silencers to fall off, resulting in tank-like reverberations riding home, not helped any by needing to keep the revs above 5000 to stop the engine from stalling. A Laser 4-2 was bought from a breaker for £30, needed some detailed hammer work to fit and bigger main jets to run cleanly above 7000rpm. It wasn't the quietest exhaust system known to man, whenever the plod were in evidence I had to sneak past in top at about 1500rpm! Top speed increased to 135mph, but there was so much vibration that it was rarely of any benefit.

It only took six months for the silencer to succumb to the corrosion. The rest of the chassis had not found an English winter much to its liking. Paint fell off the frame, engine alloy became encrusted in white crud, the oil emulsified after 500 miles and the all three calipers did the seizure trick every other week.

I haven't mentioned the brakes yet, probably because they hadn't sprung to mind. They were so good that I hardly ever had to give them much thought, even on crap tyres able to avoid locking up the wheels yet pulling me up without any trauma. Just ultra rapid, straight as a die retardation. As soon as I got back to the UK, I'd fitted a set of Avons as I just knew the combination of ruined roads, excess rain and iron rubber would've had me on my ear-hole within days.

Honda calipers are nasty pieces of work, apparently deliberately designed to corrode so solidly that the only option is to rush out to buy a new set. There's a fine line between hammering them apart and breaking up the castings. I ended up with a spare set, so that the swap over could be done in an hour or so. The complex hydraulics out front meant it'd take about 30 minutes to successfully bleed the system.

One time, some air remained trapped, I ended up with the lever coming back to the bar and no braking just as I needed to avoid the manic machinations of a cager who thought he was Nigel Mansell. Burning off a millimetre's worth of rear tread saved us, along with knocking down through the gearbox, causing a lot of chain rumble. A high quality O-ring chain and new sprockets will last about 18000 miles. Just bunging on the cheapest chain on worn sprockets is worth only 4000 to 5000 miles. A worn chain is easily noticed as the gearchange goes to pot.

The one time I left the bike for a week it was most reluctant to start. I drained the battery twice and fitted new spark plugs before it came to life with enough valve noise to turn a Vincent owner nostalgic. It was always a noisy bugger from cold, the oil needing some time to flow through the tappets before the free play was taken up, and I was reassured when the normal rustling noises returned after five minutes of near blind panic on my part.

A couple of times during the winter the voltmeter had registered zero but it seemed to come back to life again after a few minutes. I kept checking the battery acid level every 2000 miles as it'd burn off quite quickly. After about 50,000 miles there was a lot of white corrosion between the plates and a reluctance to hold a charge when the excellent lights were used in anger. I bought a new battery but the voltmeter still played up from time to time.

When it finally went completely dead I feared the alternator was blown, but after playing around with the connectors it came back to life. Looking closely at the terminals I could see bits of corrosion interfering with the contacts. A bit of work with the emery cloth had everything shining brightly and the whole of the electrical system was given some WD40 for further protection.

By the time 60,000 miles were up, there were no further signs of electrical malaise but the overall finish was poor. Faded paint where it wasn't missing. Cracked plastic and a rusted exhaust. Extensively corroded engine alloy and wheels that all the elbow grease in the world failed to shift. I went on a spending spree. Brand new 4-2 exhaust, resprayed cycle parts, blasted engine cases and wheels, and even a new pair of fork stanchions as the old ones had become pitted, killing off seals so quickly that I'd given up fitting new ones.

In this form the bike was ready for another summer's madness but I didn't have the time nor money for any lengthy tours. Performance had not diminished in any way, all the engine wanted was an occasional carb balance and oil change; not even the original camchain had started to rattle. The only thing that caught me out was when the hydraulic clutch's hose split, leaving me without a clutch 60 miles from home. I could've bodged a repair but it was easier to lurch home without a clutch and do a proper job in my garage. The feel of the clutch was always a bit remote and on a less well natured machine could've proved troublesome in attaining an easy take-off.

By the end of the summer the CBX had crept up towards the 75000 mile mark. Starting had become harder and the top end a touch noisier. The engine's quite well known for burning out exhaust valves at 40 to 50,000 miles and that may well have been catching up with me. Whether that problem's down to the four valve head overheating or some malady of the hydraulic valve adjustment is hard to tell. The most obvious theory is grit in the oil from less than frequent changes damaging the system. During town use I was doing very frequent oil changes but on tours extended the interval right up to 5000 miles. Maybe that was the cause.

I'd found the CBX a brilliant bit of machinery. It'd cruise along at 70mph with just 5000 revs up as if just ticking over. Even at the ton it was far from frantic. Top speed and acceleration were more than enough for anyone who had the slightest feeling of self-survival. Solo, handling was fine, but two-up pushed the suspension and chassis close to its limits. Decent tyres were the greatest expense, the almost complete lack of necessary engine maintenance its greatest virtue. It's the kind of bike that will do anything you want without breaking the bank.

Mine had to go, though, I didn't want to spend out hundreds on a top end rebuild. As it was in such a smart shape and still ran so well I obtained a decent wedge. Only £50 less than I originally paid, so depreciation was minimal. There are lots of reasonably priced CBX750s around, but knowing what I know I wouldn't buy one with more than 20,000 miles on the clock without doing a compression check on the cylinders, although if you're feeling brave you can check the valves by watching for smoke out of the exhaust on the overrun.

Dean