The seventies produced a whole heap of wonderfully powered but inadequately framed motorcycles. The Japanese had worked out how to build strong, powerful and extremely reliable four cylinder engines, most notably the Z1 and CB750. Those engines were heavy and wide, pushing Japanese chassis technology to the limit.
The result was overweight and top heavy bikes that twitched their back ends and shook the forks, like a dog shaking off water. You want to know fear, just ride a Z1 at 130mph over a bumpy road on stock suspension. Tyres, shocks and forks were upgraded but still the mass, frame geometry and lack of swinging arm or steering head support allowed dangerous times. The more you wrestled with the bars the worse the handling went!
Enter the British frame specialists. Most noticeably Dresda, Rickman and Seeley. Not only were the frames stronger, the geometry better and the styling flasher, but mass was shaved off the 550lb mammoths, most notably on the Dresda which weighed in at a mere 450lbs. Not exceptional by today's standards but back in the seventies it was a minor miracle.
The Dresda's tubular trellis was an evolution of the old Featherbed frame, which Norton had abandoned when they found their 750cc Atlas engine tried to vibrate it to pieces. Dresda proved their chassis in various endurance races when it was equipped with a detuned Triumph 650 engine. In theory, the four cylinder CB750 motor should have proved smooth, but some mismatch between the engine and the lightweight chassis made the bike vibrate quite furiously between 5000 and 7500 miles on the high mileage and somewhat worn example I tried.
Even a stock CB750 can be blitzed by vibes, the K2 and K3 models being especially intrusive once past 30,000 miles. I suspect wear in the hyvoid primary drive chain setting up a resonance throughout the engine as it seemed out of all proportion to the secondary vibes you might expect. The Dresda frame employs high tensile, thin wall tubing - very strong but far from ideal for absorbing vibration.
Any pain that arises from the vibe's much amplified by the riding position. The Dresda imitates the extremes of those old Tritons, with its clip-ons halfway down the fork legs and an extreme reach over the large petrol tank...This works extremely well at about 120mph when I could get my head down and rest some of my weight on the dubious GRP tank...At 30mph in rush hour London traffic it was like being stretched on the rack whilst someone tickled my spine with a sledge-hammer!
The motor was also in a hot state of tune. Cams with lumps as big as a Page Three girl gave it a nervous tickover that varied between 1000 and 3000 revs, whilst the four into one exhaust let out a bellow like an old war plane trying to pull out of a dive. The steering lock would've impressed an artic pilot whilst the steering was as heavy going as a tractor, down to a lack of leverage from the bars and a big front wheel with a lot of weight over it.
All that fades away when the swervery's hit. Then the bike flicks from side to side with a precision more likely to emanate from a nineties 600 than a seventies four. The frame's really good, even when running on old-fashioned and therefore thin Avons, able to keep the back end in line when the power pours in hard at 6000rpm. On the stock bike, on a bumpy road, it could have you off if you hit the throttle too soon. On the Dresda, the worst that happened was a bit of back wheel twitching and the GRP rumbling with the vibes.
How to piss off a modern retro? Easy, just use the Dresda hard through the curves and watch them ride off the road trying to keep up! Its length means some muscle's needed but it ain't tiring because of the excess of adrenaline generated. Through curves the bike's about 20 to 30mph faster than stock, not just because of improved chassis dynamics but also because it feels one hell of a lot safer, encouraging you to take it to the limits.
Those limits are found in the grip of the tyres...I could almost feel the spoked wheels distorting. If you put these kind of tyres on a CBR600 it'd probably turn into a wheelbarrow, god knows how good the Dresda would be on fat radials...the owner just laughed when I suggested this, pointing out that instead of getting 3 to 4000 miles, the older style rubber lasted for more than 10,000 miles. Spoked wheels are lighter than most cast jobs, such diminution of unsprung weight giving the rubber an easier time. Modern bikes are huge rip-offs in many respects.
However, I was less impressed with the tyres one typically wet day. The Dresda actually had a better front guard than most modern sporsters (come on chaps, you pay six grand for a replica that's completely covered in crud the first time it rains...) but still a lot of spray hit the engine which caused it to cut out.
Churning through the bends with an on-off engine resulted in a huge increase in my laundry bills and a bloodied tongue. To be fair to the Dresda, it felt quite secure in the wet when the engine wasn't misfiring or heavily into its powerband. Perhaps not as inspiring as an old Norton twin but far better than some modern fare.
I suspected that the vibes were either frothing the fuel or attacking some component in the electronic ignition - 300 miles into my tenure the oil tank started leaking, despite having some excessive rubber mounting. I found out about this when the back wheel went into fish-tail mode as I indulged in a little traffic light drag racing. It was vicious enough to make me stop worrying about the clutch rattle. The owner had a spare, if patched, GRP oil tank and didn't seem surprised.
That failure confirmed my general impression of the Dresda CB750. A fine chassis that made the best that could be done with the engine, but its radical riding position and weight paring were a touch extreme. Maybe a modern version, using, say, a CBX750 engine would work much better but then the CBX doesn't suffer from the same handling deficiencies, although it would undoubtedly benefit from losing 25% of its mass.
A Dresda, with a hot-rod CB750 engine and full fairing, will touch 140mph under favourable conditions, but it's not a speed you'd want to hold for very long, thanks to the eye blurring vibration. Still, it's a hard enough bike to make modern replica riders question their choice of steed.
These bikes are now very rare, prices varying from £750 to £3000. The lower end's usually been used on the race-track and well thrashed. Some road bikes have been hard used because they are so much fun and I haven't yet seen a really nice one.
It was some time later, long enough to forget the back pains, that I got my leg over a Rickman CB750. The petrol tank's about as long as you can get without ending up sitting on top of the back wheel. The long stretch and low bars were made much worse by the well finished fairing snagging on my hands and, er, neck. Ergonomics wasn't a concept that Rickman readily embraced, although the general finish, from nickel plated frame through to the GRP, was better than the Japanese standards of the day. The bike still shone beautifully.
The Rickman's frame was not dissimilar to the Dresda's effort but there was more mass; overall stability a higher priority than flickability. If anything, the level of discomfort was higher on the Rickman, even if the vibration was noticeably lower, as the edges of the tank and frame lacerated my thighs unless I wore long-johns, jeans and water-proofs. As it was summer and the fairing wafted up the engine heat, this was not too inspiring.
The CB750 engine, this time, was a stocker to the extent of running a standard exhaust system...Rickman cleverly allowed the owner to use the maximum number of OE components on their frames, upgrading further when money allowed (Rickman's excellent front forks are so superior to stock they are almost a mandatory purchase).
In this state the bike lacked the hard edge of the Dresda but was much more civilized. Discomfort apart, I felt very safe sat atop the bike with none of the excessive fear and loathing of the stock CB750. Even running hard through a series of bumps in corners failed to start any twitching and in the one downpour I experienced a feeling of security on the greasy roads that was so shocking there was no need to back off. The only trouble was, every 50 miles I had to jump off to leap up and down to get the blood flowing through my body and straighten my spine. God knows how many young kids ended up hunch-backed.
The only time the bike went way out of line was when I launched it off the summit of a steep hill at about 90mph. I'd found these back road which were a series of switch-backs and radical hillocks. I left my stomach behind many times and flew through the air like a rocket going off.
This time the bike came down with an almighty thump that rattled my spine and teeth. The whole chassis squirmed, shook, rattled and rolled. We were all over the shop for a 100 yards, the frame turning plastic. Afterwards, I found that the taper-rollers in the steering head were a touch loose, but I didn't get the chance to repeat the experience to see if that was the cause.
To be honest, for all its obvious ability, I found the bike so lacking in comfort that I didn't really want to know. When I explained this to the owner, he took me into the depths of his garage, revealing a Rickman Z1 with proper handlebars, shorter, fatter tank and a luxurious saddle. I fell in love with its lines and would have bought it there and then...save that the owner wanted seven grand for it!
It was low mileage, immaculate and beautiful. It was, however, still too wide around the saddle/tank interface with the feeling of being perched far atop the machine. I was only allowed a brief blast up the road. Long enough to reveal that the handling was up to the other bike's standards, that the Z1 motor had massive grunt and less vibration than the CB750, and that it was generally confidence inspiring.
I was so enthusiastic that eventually a weekend aboard the bike was allowed, having made a vague promise about putting the wife on the game to pay for it.
It's not many motorcycles that can inspire such lust in my heart these days, as age brings with it a certain cynicism. The Z1 mill, in stock condition, is still a ball. It has a directness in laying down its power, helped along by the Rickman's lower mass, that seems to elude modern motorcycles, new Tridents apart.
Couple that with the excellence of the Rickman frame and the increased leverage on the upright bars...taking the weight off the front wheel, though, could cause the forks to shimmer under harsh acceleration out of corners. It was in no way frightening, adding to the sheer thrill of hustling the bike down my favourite country roads.
Regrettably, after 200 miles discomfort hit my groin and thighs again and I could see that trying to ride hard, long and fast would be a bandage job, the bike definitely needs to be more waisted in its centre. No way I was going to pay big money for such a seriously flawed bike. Great for posing or short distance hustling, though.
It's weird, once you begin getting interested in specials they start turning up everywhere. Next came the Seeley version, not dissimilar to the street Rickman only with more attention paid to details. The owner wanted silly money, five grand, but was persuaded that a long weekend in my hands and unlimited fame in the UMG might help sell the cycle, though knowing the meanness of the average reader I have my doubts.
Comfort was far ahead of any of the other Honda based specials, though it still had a way to go before it could match a sixties BMW boxer. 200 miles in one sitting didn't turn up any unbearable pains but too much town work had my back muscles screaming in anguish.
The engine was stock, save for the exhaust and airfilter. However, 33000 miles had left it as rattly as a half empty dustbin and as powerful as a modest middleweight. The weight saving from the Seeley chassis appeared minimal, the geometry set up to inspire straight line stability rather than flicking through the bends like an RD.
The heavy feeling and lack of power made the Honda feel like a relic of the seventies. The gearbox was something out of the sixties...plain nasty! These elements combined to make the bike a bit of a pain anywhere other than on the open road. Even then, roaring past cars above 90mph made for some expletives because it took a hell of a time to accelerate to higher speeds. I'd sit there wondering if I was about to die. The brakes were good, in extremis I could duck and dive to survive another day. A couple of times the bike fell out of gear; 15000rpm didn't kill the engine dead. Sometimes I got off the bike with a taste in my mouth reminiscent of bad sex.
The most I saw on the clock was 130mph, left me feeling queasy with all the effort involved. Hand and foot hovered over clutch and gear levers. The most impressive part of the bike was the way a series of bumps failed to throw it into a weave or wobble. Despite its obviously worn state, very little vibration managed to get through the chassis.
Sometimes the sheer mass of the bike bit back. Hitting a patch of diesel caused the rear wheel to swing out viciously. Felt like we were going sideways for a few frightening seconds. My instincts were at a loss to react, sat there as if in the throes of a heart attack until the chassis sorted itself out. On a stock bike I would be dead or a hospital case.
Riding with a couple of modern bikes showed the Seeley up as being past its sell-by date. The buggers rode both inside me and outside me, crossed me up and generally put me in my place. There were obviously much better ways of spending large amounts of dosh...
I saw the advert in MCN. Honda Britain, needs attention, £500. I hustled over to the other side of the capital so fast time was nearly reversed...no, it was just my fake Rolex falling apart. Last of the line OHC CB750 with old-fashioned full fairing, flash paint job and upgraded suspension and brakes. No MOT as the forks were shot and the swinging arm bearings loose enough to make it as rat of the year. Paint and rust vied for domination.
I played with the throttle like a crazy kid, the gears engaged and no oil leaked. Must be okay, then. I slipped the guy 450 notes before some other likely lad turned up and rode the bike home, getting a mate to take me back to pick up the other machine. A pair of gaiters on the forks and new swinging arm bearings were all that were needed to obtain an MOT.
The Britain's handles much the same as a stock bike, the worn out forks making for an interesting shuffle. I could hold on to the course, ignoring the looseness didn't do any harm. There must have been some high lift cams or something in the engine, as it howled down the road at a fearsome rate. I had trouble holding on to the bars, even more so when we hit 140mph and an outrageous speed wobble. Lesser mortals would've thrown up, I just loosened my grip on the bars and let the wobble die out of its own accord.
Right, be sensible, go buy a used set of F2 forks. These were a bit pitted as well but new seals and springs meant for a tractor reassured me that I had more chance of ending up in heaven than hell. The forks were an inch longer than the ones they were replacing, the change in geometry causing the bike to fall into corners with the same kind of viciousness as a GS Suzuki when the front discs are applied.
Lurching down to the tarmac on a 500lb monster was as exciting as being set upon by a pack of crack addicts. The remorseless nature of this demise made me revert to a more primitive point and squirt technique, even to the extent of defying gravity and the nose in the trough geometry by getting the front wheel way up in the air. The straight through exhaust made this one hell of a ball until I went deaf, was clobbered about the head by enraged plod and pursued by packs of angry peds.
The Honda was too much of a carthorse for the modern world and the riding position was tearing my spine apart. Sold the heap for £750 after about a month. Not a bad deal, that. The other specials, unless you get lucky, are too expensive for what they offer, which is more pain than pleasure. Modern bikes handle just as well, are cheaper and less trouble. The only one I might lust after would be the Dresda, but only if fitted with flat bars - its lack of mass makes it a more compulsive experience than the others.
Dick Lewis