Sunday, 17 May 2020

Triumph 650 Thunderbird



There she stood in all her glory. Chrome, alloy and paint gleamed. Bolts were wired in. Rocker covers had little springs between them. Lots of neat little detail points. The exhaust blared beautifully. The whole chassis went into a vibratory dance on its stand. Wanted to skip across the ground. Hmmm! They're all like that, thought I, especially the big 650’s.

I was down £3500, had bought the bike on a whim! What happened was that I'd gone to the BMF rally and ended up talking to a group of Brit bike enthusiasts. I was on my well renovated Honda CB400F, which could, in some ways, be considered an honorary Brit - being mild and pleasant, in no way excessive. The owner of the Thunderbird was a giant of a man who let drop that he was on the track of a Vincent and might want to sell the Triumph quickly. We swapped phone numbers. The day before he called I’d been offered £1500 for the Honda. Fate was obviously telling me something.

My first day’s ride went something like this. A few moments of panic when the compression did a runner and I seemed to be kicking the engine over as if the clutch was pulled in! Then she caught, though the compression suddenly coming in nearly broke my right leg. There’s an acquired art to kicking over old Brits and a moment of inattention can lead to a broken ankle or even leg if the engine suddenly kicks backs!

Nearly broke my left hand pulling in the clutch lever. Thought, wimp, I'll soon firm up my muscles but it was always a pain in town when the unit would overheat a little. Bring in some drag, make the bike difficult to control at low speeds or a standstill. The oil would also seize up the plates overnight, making it mandatory to turn the engine over on the kickstart a couple of times with the clutch pulled in before trying to start the motor. The non-standard Amal carb had a cute little button that was depressed to prime it with petrol, which would cascade out. Tickling the carb was quite reassuring as at least | knew that the petrol was getting through. With the carb tickled there was no need to use the choke on even the coldest day.

On a good day she'd fire up first kick, on a bad one she’d take ten or more exhausting kicks. One aspect I certainly didn't like was that when the engine stalled when hot it would sometimes sulk for five to ten minutes before starting again. You can imagine how angry this made cagers if they couldn't swerve around the bike or knock me off!

Out on the road for the first time. Feel that meaty torque, made the Honda four seem very wimpy indeed. It was fairly brutal with hardly any sophistication in the way it took up the power. Almost as if the bike wanted to get going with indecent haste. Once the clutch lever was past a certain point it jumped viciously forward.

Try to engage second gear only to find the thing locked into neutral. A real struggle with the gear lever as it’s on the wrong side compared with my normal Jap iron and needs enough pressure to rip my leather shoes apart. Pull over, only to find that the forks are jerked viciously to the right. Did | bring my heart tablets?

Back into first, an almighty boot and she went into second and then third. Triumphs are supposed to have slick gearboxes but this one had a distinctly vintage feel, was almost as bad as that fitted to a BMW R60 that once passed through my hands - at the time I couldn't believe that a supposedly sophisticated bike could be so agricultural but experiences with other old style BMW boxers just confirmed my initial impression.

When I tried to rev through the 6000rpm mark the engine went into a series of stutters. Slicked into fourth gear, tried again, but no hope of getting through that barrier, though in second or first it'd bound up to 8000 revs without much restraint. In fact, I had to stop myself from winding on the throttle too rapidly. Most people would as only those who don't mind their eyeballs falling out and all extremities getting a strenuous vibro-massage would persevere with thrashing a 36 year old engine. The sheer age of the machine puts most complaints about it into perspective and there’s no real way of knowing what previous owners had done to the poor old thing.

The basic feel of the Thunderbird was exactly what you'd expect from an early sixties motorcycle - rough and ready with every aspect of the machine, feedback from the road as well as vibes, hitting the rider like a slam in the teeth from a baseball bat. It made the Honda, which in relation to modern Jap fours is distinctly out of the game, appear a paragon of advanced engineering with the smoothness of a turbine and ease of use of a TV.

After a fifty mile blast down the local country lanes I returned home as if I'd done a twelve hour day of hard labour. Although light by modern standards, at well under 400lbs, it was quite heavy going when steered through the bends at a reasonable pace. The big front wheel on thin rubber was most probably the culprit. It was an amount of effort that diminished as I became used to the Triumph. Only noticing it when leaping aboard modern bikes and finding that the same kind of input had us all over the shop like an accident looking for somewhere to happen.

I was going to sneak back indoors when I noticed that the pre-unit engine was leaking oil. The return oil pipe was waving around like a small snake about to strike - the residual energy from all the vibes had given it a case of the shakes. Then I saw that two rocker caps had gone AWOL, despite the spring that was supposed to stop them unfurling. Various nuts had disappeared off the chassis. And the rear light assembly had disappeared completely - apart from the ignition the electrics were completely dead as a couple of wires had shorted out and blown the fuse. Not that the front light or horn were up to much, being original Prince of Darkness fare.

Cry? Too true. Trouble was I couldn't mouth off to the nearest and dearest as she was still sulking about the amount of dosh I'd blown. I had to pretend that all was sublime. New rocker caps, loads of Loctite and all the screws and nuts gone over, I thought I had the bike sussed...

The electrics were another country, with a couple of years worth of bodging. The whole lot in desperate need of an upgrade. I ended up with Boyer ignition, 12V conversion, modern rectifier/ regulator and a complete rewire. Not to mention new lights all round.

Even this great effort still left the bike in a potentially weak state because there was just so much vibration coming off the engine that few relatively fragile electrical components were able to survive. The electronic ignition being the exception - it definitely aided starting. Never more than three kicks needed from cold and hot starting was instantaneous. Hurray for some good news.

The next time I went for a ride the bike didn’t want to go beyond 5000 revs in any gear. As this coincided with minimising the buzzing it wasn't that bad. There was plenty of torque, though it was at those revs that there was a sudden torrent of power. Whilst. riding around I pondered if it were the carbs, electrics or mechanics that were giving the trouble. What I needed was a Triumph expert.

Before I could find one I experienced my first ever speed wobble. I've known many Jap bikes that were vague, weaved and wallowed a bit, but the way the Triumph went down was entirely different. As the handlebars hammered from lock to lock, and the Thunderbird skittered from one side of the road to the other, the whole tubular frame gave every impression of being transmuted into rubber or plastic.

Neither wheel wanted to go in the same direction of what was left of the frame. The violence of the wobble was such that I couldn't even see straight, let alone form a coherent thought. My mind was filled with fear and dread that these might well be my last moments alive. What a way to go. Though in retrospect I suppose there are a lot worse ways to die - it’s just that I didn’t think like that at the time.

I wrestled with the handlebars - bars, incidentally, that were fashioned perfectly to accommodate the human body in more normal circumstances - the oscillations amplified further, giving every impression that the forks were going to snap off at the headstock and I was going to end up scraping along the tarmac on my knees at 70mph. Just the thought of it makes me want to throw up, let alone the nasty reality.

For a little while | just sat there, hoping for divine intervention. In the more sane moments, I was able to realise that there was an actual limitation to the size of the oscillation, which luckily coincided with the width of the road! Just as well it was a deserted country lane without any predatory cagers hanging around, though they might well have dropped a load at the fantastical sight of the Triumph and its cringing rider.

From some recess of my mind I recalled the solution to my near death experience. Remembered that the worst thing you could do was try to fight the wobble as that only resulted in it increasing in amplitude. God knows where that nugget of information came from. I eased my grip on the bars and gently rolled the throttle back.

Initially, I thought I mucked things up in a big way as the old heap gave an almighty, desperate shrug, just like some big old horse refusing to do a jump and trying to throw its rider right out of the saddle with a mixture of pleasure and violence, but then it went back to its previous antics. As speed decreased to 50mph the bike snapped out of its suicidal instincts and quietened down again. Almost as if a miracle had been performed and, magically, I was suddenly aboard a completely different machine that actually had some metal in its frame and wheels that pointed in the same direction.

I pulled over. I was in a right state - weak of leg and not far off bursting into tears, if only of relief. It was like being on solid ground after years at sea. When I stopped shaking, I kicked the wheels, had a fight with the forks and swinging arm, but could find no incipient looseness. I bravely resumed mv ride. thinking of that song, gone wild in the country.

Handling was, anyway, a rather weird mixture. Suspension was so taut that it could take a couple of sumo wrestlers and only reacted to the deeper pot-holes. The tautness went along with the lack of travel, three inches maximum. But it was never precise, the front end wavering a little as speed increased and the back end feeling a bit hinged-in-the-middle when the bike was snapped through a couple of bends. This era of Triumph could not compete with rival Nortons in the bends but had a better reputation for their engine toughness (although: this was relative and somewhat laughable in comparison to modern bikes).

With all its mystique I was expecting something special but in reality it couldn't really keep up with a mediocre Jap middleweight, like a Suzuki GS450E! Back to the engine problem. I needed something to take my mind off the handling and even an excuse to avoid riding the bastard. I couldn't find anything wrong with the carburation and electrics, began to suspect that there was a serious malady with the motor.

I took the cylinder head off. This was when | became really depressed. The head had two large cracks running through it. It was the old, weak eight stud job rather than the tougher, later nine stud item. At least the valves looked OK and the guides weren't leaping up and down, as they have a tendency to do.

I eased the cylinder off, suspecting the worst. The piston skirts were a bit scored but still useable. It was the big-ends that got to me, loose being an understatement. The 1961 model had a pre-unit engine which meant it was at least easy to whip the whole motor out. Except that the gearbox was never slick like a Triumph should be and that the chain primary chain was so worn that large grooves were scored in the chaincase.

I'd been done! The annoying thing was that the motor ran well enough, initially, to convince me that it was a good ’un. As it was a private deal there was no easy way to get my money back. The oddest thing was that it was the very toughness of the motor, its ability to run seemingly fine when in a desperate state, which had caught me out. Probably the only way of sussing such a mill is to have an intimate knowledge of the amount of vibration a good motor puts out. Which is much easier said than done if you're coming back to British bikes after a long absence.

There followed a few months of wandering around autojumbles, bargaining down the silly prices demanded for various engine parts. The major expense was a rebuilt crankshaft which I had dynamically balanced. Putting together an engine with bits from different sources, with varying states of wear, is a recipe for disaster. But the Triumph came together easily enough and the distinct lack of frenzied vibration convinced me that I'd finally assembled a good motor.

Whilst the engine work was going on I'd fitted new steering head and swinging arm bearings, new brake shoes and also rebuilt the gearbox with used parts, finished off with a new primary chain. The overall cost was in the region of four hundred notes; not bad by modern standards but appalling given the amount of dosh the bike had cost.

The final machine was transformed. Rewed happily up to 8500 revs in all gears, which now slickly engaged. Vibration was only heavy going above 6000rpm. Handling was still on the vague side but it never went into a speed wobble, even when pushed up to 115mph on the clock. Fuel was a reasonable 55mpg. Comfort was close to excellent (once used to the buzzing). Braking was marginal at best, often slamming the throttle shut was more effective than using the drum brakes!

I did about 8000 miles on the bike in this state. Then it started to go off again! | wasn't going through all that hassle again, so I sold it for £2900. A loss, for sure, but the peace of mind gained was well worth it!

John Trent