I don't know whether to start this tale with a disaster or one of the highs that come from riding a classic British twin. Any extended exposure to a Triumph Bonneville will turn up lots of horrors that are usually compensated for by the sheer on the road bravado. A well set up 750 twin, ridden within its limits, can be sheer joy, with its thumping torque, narrow, stiff chassis and, er, live feel.
The latter can be confused, by those not used to its ways, with vibration. Not even the most ardent Triumph twin fan would say that the engine was smooth at 7500rpm, but between 2000 and 6500 revs, where most of the power and torque is packed, the sensation coming from the motor is more a communication of the progress of the combustion cycle that the gut churning, eyeball popping buzzing so well defined my those rotters who can only find praise for Japanese iron.
There are ways to make the long stroke engine emit frightening levels of vibration, the easiest being merely neglect of balancing its twin Amal carbs, adjusting its two pushrod operated valves per cylinder and refusing to go over the bolts every week; an act that any long term owner views as the closest a motorcyclist can get to religious communion with their machine.
There are certain mods that are mandatory for smooth running and long engine life. The most obvious being electronic ignition, which as well as removing a maintenance chore dramatically improves starting and fuel economy. The latter also benefits from fitting sixties silencers and airfilter as over the years emission controls emasculated the engine, dulling its performance edge and efficiency. A stock T140 might only manage 40 to 45mpg and 110mph whilst one modified as above does around 60mpg and 115mph - it'd probably go a touch faster but the vibes above 7500rpm are a real limitation on throttle abuse. The old style silencers also look and sound much neater.
There are lots of stories about Triumph twin engines blowing up in a big way. It may well be that some Friday afternoon specials did fall apart rapidly but in my experience a well built Triumph twin engine, using good quality components, should last for 25 to 35000 miles before needing a full rebuild. It's possible for a crankshaft, in an engine that hasn't been revved excessively, to go twice that distance and it's still easy enough to find used spares in good condition, so that a rebuilt top end can be done for a few hundred quid. There seems no reason to me why these bikes can't be endlessly recycled.
The first signs of wear will be found in the bores or the valvegear, evidenced by either smoke out of the exhaust or an increase in vibration. Being immersed in Triumph twin lore I can usually tell the state of a motor just by revving it at idle and going for a brief test ride - if you've never owned a British twin it's a good idea to take someone who knows what they are doing because it's all too easy to buy a real dog that only has a few hundred miles of life left. The tales of rip-offs could fill even a whole edition of the UMG!
My own on the road failures in seven years of hard riding that has put more than 100,000 miles on the clock (though not one clock, speedo's expire every 30,000 miles or so), have been limited to five occasions. Two partial engine seizures (worn oil pump), one clutch drum explosion (it was whip-lashed by a wrecked primary chain that in turn had eaten its tensioner), one burnt out exhaust valve (unleaded petrol or poor quality valve material) and one burnt out wiring loom (old age, vibration and rotten insulation).
Doubtless, had not 500 mile maintenance sessions been done with religious devotion, then there would've been many more minor misfortunes - also three engine rebuilds have been done as preventative maintenance. But I can't, in all fairness to the Triumph, complain too loudly over its indiscretions given that in return I've had lots of fun and done many, many miles.
The chassis was altogether easier to keep in shape. Many Bonnies came out of the factory with a poor finish, shedding paint and chrome the first time a bit of bad weather was encountered. Over the years they can decay quite majestically but it's mostly just a matter of upgrading the cosmetics because the dynamics of the chassis are right on, that unique blend of stability, flickability and light weight that the old British factories did so well.
The frame can be a weak spot as the main spine part, which carries the oil, can crack up - the excess of leaking lubricant that results is pretty obvious. Welding usually suffices although I never had this problem - it's probably a symptom of engine neglect or wear or thrashing producing too much vibration for the frame to bear.
Early versions of the frame had a tall seat height that left the rider perched high above the bike, even if you have long legs these are best avoided. The geometry's good and the stock suspension taut until wear takes ahold. I run mine on more supple Koni shocks with progressive springs in the forks (gaiters are necessary unless you want to change the seals every 5000 miles), which suits the 400lbs of metal well, giving a good compromise between comfort and stability.
The riding position I've altered to a slightly more sporting stance, which with a re-upholstered seat, allows about 300 miles in a day before my hands and feet decide that they've had enough of the engine's thrumming. I have done as much as 600 miles in a day but I wouldn't recommend it as a regular occurrence.
The only limitation on cornering was ground clearance but with modified exhaust, pegs and stands the old girl could be taken over to the edge of the Avon tyres, when bumps made her squirm around a little but it was so far from being dangerous that I would often open up the throttle, let the torque thump through the machine and exit the bend with a bit of tail wagging. It looked impressive and confirmed my status as a mad bugger but in reality never came close to letting loose.
The bike came with cast wheels and a disc brake at each end, but after a couple of years I went for spoked wheels with a front disc and rear drum; a combination superior in braking and a bit cheaper on the consumables. Brake pads, tyres and even chains all lasted for more than 15000 miles, which with the fuel consumption made the bike as cheap to run as many a Japanese 125 (oil consumption was high but I used cheap 20/50). The bike, by the way, remained stable on tyres with a mere 1mm of tread.
Such frugality does endear the Triumph to me, making up for some of the other expenses. At least its life is predictable, I can count on at least 25000 miles from a rebuilt engine, which gives me the time to buy the bits I know I'm going to need from autojumbles. I also have a second engine undergoing reconstruction with a couple of trick parts that should take the Triumph twin experience a little further.
It's not the kind of bike you can ignore and thrash mindlessly, it needs a lot of tender loving care along the way. Given that, the payback is a neat bit of engineering that can be modified to suit your personal tastes and needs, which is always fun to ride on the open road and whose slight lack of predictability always gives an edge to every outing.
David Redstone
****************************************************
Back in 1980 I was an innocent youth whose pride and joy was a seven year old GT250. I'd always fancied owning a British bike, though, and when in September that year I came into some money I looked around for a Bonnie - at that time the only British bike in mass production. A 1978 model was advertised in the local rag by a nearby dealer so I went round in my lunch break to take a look.
The dealer was just finishing his dinner when I got there and reluctantly strolled out to start the bike. At the twentieth kick it started up, by which time the dealer was suffering indigestion and I was worrying if I'd have to go through this procedure every morning. The throaty roar from the exhaust convinced me I had to have the bike and next day I paid £995 and rode off on it.
A Bonnie must be the absolute antithesis of a GT250. Riding it home that first day, I was amazed to discover engine braking (sure that shouldn't have been breaking? - Ed) - a concept unknown on a GT. As soon as I eased off the throttle it felt like something had jammed the anchors on. The controls felt very stiff and the switchgear primitive. The indicator switch, in particular, was very fiddly to get right which I cured by junking the indicators.
The Bonnie felt much heavier than the Suzuki, although in reality it only weighed a little more. It was also much harder to kick up - I soon developed much larger right leg muscles; real man's bike, I told my mates. A week after buying the Bonnie, I decided to test it out by doing the 100 mile run to Nottingham University.
I'd never done a long trip by bike before and was a bit apprehensive, particularly as it was pouring down and I had a habit of throwing bikes up the road in wet weather. The journey began well but as the engine warmed up the clutch began to drag and I had problems in one traffic jam. No way could I get neutral (trick is to find it before you stop) and I was having to rev the bike to keep the engine running, whilst simultaneously applying the brake to combat clutch drag.
I needn't have bothered; soon as the traffic started moving the damn thing stalled anyway. I arrived at a Godforsaken place called Duffield at the same time as a blizzard and, when braking suddenly, threw the bike up the road in a big way. I was aware of a great pain in my left wrist when I picked the Triumph up.
The bike was ridable - just cosmetic damage really, indicators gone and a bent footrest. I kicked it into life and pulled the clutch in. Ow! That hurt! After stalling it about four times trying to start off and having to let the clutch out prematurely I eventually resorted to mind over matter and forced myself to hold the clutch in until the bike was moving.
Once mobile I used clutchless gearchanges the rest of the way. I parked in the centre of Nottingham and got a taxi to my friend Hawk's digs. After tea and sympathy he drove me to the campus. As it happened the whole weekend was a disaster as my better half was in a foul mood the entire time and I ended up catching the train home as my hand swelled up like a balloon - turned out to be a broken scaphoid so I spent the next six weeks in plaster up to my elbow.
That was a frustrating time with my new bike stuck in Nottingham and me on Merseyside, both wounded. Luckily Hawk had the situation there under control and arranged for a dealer to collect the bike and repair it, so the time wasn't entirely wasted. When I did eventually get the bike back it had been transformed - the controls seemed much lighter and easier to operate, it started first time and ticked over perfectly. Even the clutch worked.
Apparently, it had been way out of tune and the cables had never been oiled since leaving the factory. I gradually got to trust the bike's reliability and in '81 it completed the End to End run without undue hassle (see UMG 19). Later that year a fellow Bonnie owner introduced me to the local Triumph Owner's Club and soon I was a regular at rallies and runs.
To anyone who isn't in a bike club, take my advice and join one - you get more enjoyment from biking when you do it in company. There's also expert (and otherwise) advice on hand - I soon made the acquaintance of a friendly bike mechanic which was handy with my abysmal mechanical knowledge.
In 1982, after I visited the Meriden factory (now turned into a housing estate with roads named after various Triumph models, I think) the bike went through a spell of bad behaviour. It seized a couple of times and the crank sheared, all for no apparent reason. My mechanic crony had a lucrative time.
One incident stands out. After 250 miles of rain the bike stalled and wouldn't restart, so my pillion gave a push. The only problem was that when it started the silly bugger forgot to let go and was dragged along on his knees. I pulled up and looked around, expecting to see him running up to jump back on the pillion, and instead saw him picking himself up off the road with a queue of bemused car drivers looking on!
I got a new job in Leyland, Lancs, in '84. It was 40 miles away and for six months until I bought a house there I commuted daily. With leisure trips I reckoned to average 500 miles a week - not bad for an old Bonnie. Mind you, I give it a full service every month. I wouldn't like to guess what the total mileage the bike's covered in its lifetime would be (speedo/mileometer hasn't worked for many a year) but it must be pretty horrendous.
One day in May '85 I'd been working on the bike in the road opposite my house until dark and couldn't be bothered wheeling it into my back yard. Next morning I went out and there it was - gone! Real sinking feeling inside as I rang up the Old Bill to report it stolen.
Two weeks later it was found in a ditch, looking very sorry for itself. The clocks and ignition switch had been smashed off and the headlight broken, plus the odd dent and scratch here and there. Having said that, it had degenerated into a bit of a rat anyway before the low life pinched it, so I decided to strip it down and do a full restoration.
By this stage in my evolution as a spannerman I could put a motor back together no problem, but I had trouble taking them apart and the bike was in my yard for two years whilst I struggled with seized studs, mounting bolts, etc. Gradually it was transferred, bit by bit, to my spare bedroom for renovation. I did the full works. Frame stoved, new loom, motor rebuilt with new valves, pistons, bearings and bushes. I found the factory parts manual very useful for this type of job. The restoration slowly took shape. As it neared completion we heaved it down stairs for final assembly, adding wheels, mudguards, etc.
In March '88 the great day dawned and we poured some juice in the tank, switched on and kicked it over. It started about the sixth time with three years worth of rust and dead insects splattering out of the exhaust and all over my kitchen. Took a bit of tinkering to get the carbs and timing right but soon I was mobile again.
It felt really strange to be back on the old steed after a three year layoff. The bike didn't seem as smooth as I remembered it, but I had been riding a borrowed VF400 immediately before, so, I suppose, any Brit bike would seem like a boneshaker after that. I went to a couple of Triumph Owners Club rallies that year but the longest run was to the Riders Rights demo in Hyde Park.
That was a scream - 25000 bikers bringing London to a standstill. Later that year I acquired a Cage and the Trumpet began to get a bit neglected, partly because I was now back living with my folks and therefore banned from working on the bike indoors.
My lack of maintenance backfired on me, literally, on a run to Manchester. First, a silencer fell off - I went back for it and strapped it to the rear rack. Further on, overtaking a van, there was a bang, smoke everywhere and sudden loss of power. I noticed the carb inlet balance pipe had come off, allowing a weak mixture to the right-hand pot.
Sure enough, a stripdown later revealed a holed piston. At the time I carried on with one cylinder as we were nearly there and I didn't want to miss the party. I took the whole motor apart to clear out any swarf. Once again, made a few cock ups while dismantling, most of them too embarrassing to mention. Getting the crank out of the cases, I put the whole thing in the oven to loosen off the bearings. Took it out, expecting it to come apart easily but it didn't. I stuck a centre punch in the crank and hit it with a hammer. Bang! End of centre punch broken off and wedged firmly in the crankshaft oilway.
Oh dear, I thought. Turned out mum had got one these new fangled slow burn ovens which never get very hot. Asking around for help, I found a guy at the bike club whose firm possessed a spark eroder machine, only problem was he had to sneak the crank in when his boss wasn't looking and it was about three months before I got it back.
Once I'd collected all the new parts it went back together easily in a few days and has been behaving itself ever since, though the perennial oil leaks are still there. Over the years I've carried out a few mods to make life easier. One is a heavy duty 630 chain and sprocket kit which has doubled the mileage between chain adjustments. Another is fitting a handlebar choke instead of the naff carb mounted item which was always going wrong. A sealed beam headlamp from a Mini will fit straight into the Bonnie's headlight shell, so I buy them from a car breaker to save cash. Also, Mini Cooper brake shoes fit the Lockheed calipers.
In todays' traffic I can still keep up with the commuting hordes okay. I'm usually first away at the lights unless some inadequate wimp with an XR3i or similar decides their fragile ego needs boosting. On the motorway it's a different story - Bonnies don't like them, but then neither do I, so it's no great hardship to avoid them.
Brakes are nothing like as good as the latest Jap stuff but you learn to anticipate well in advance - proof of the risk compensation theory as riding Jap stuff I storm up to obstacles and haul the anchors on at the last minute. The top speed is supposed to be around 110mph, though the fastest I've done on mine is a straight ton. I slowed down out of mechanical sympathy. Average mpg is around 50mpg. I did once get 74mpg by sticking to 3000 revs (50mph in top) everywhere. I'm continually advised to lock the bike away and flog it in ten years time for a fortune, but I'd miss riding it too much.
A lot of people are amazed I've kept the same bike for ten years. However, a basic tenet of philosophy is that change is indicative of unhappiness with the status quo. The fact is, I'm perfectly happy with my Trumpet, so why change it?
Dave Pearson
****************************************************
Back in 1980 I was an innocent youth whose pride and joy was a seven year old GT250. I'd always fancied owning a British bike, though, and when in September that year I came into some money I looked around for a Bonnie - at that time the only British bike in mass production. A 1978 model was advertised in the local rag by a nearby dealer so I went round in my lunch break to take a look.
The dealer was just finishing his dinner when I got there and reluctantly strolled out to start the bike. At the twentieth kick it started up, by which time the dealer was suffering indigestion and I was worrying if I'd have to go through this procedure every morning. The throaty roar from the exhaust convinced me I had to have the bike and next day I paid £995 and rode off on it.
A Bonnie must be the absolute antithesis of a GT250. Riding it home that first day, I was amazed to discover engine braking (sure that shouldn't have been breaking? - Ed) - a concept unknown on a GT. As soon as I eased off the throttle it felt like something had jammed the anchors on. The controls felt very stiff and the switchgear primitive. The indicator switch, in particular, was very fiddly to get right which I cured by junking the indicators.
The Bonnie felt much heavier than the Suzuki, although in reality it only weighed a little more. It was also much harder to kick up - I soon developed much larger right leg muscles; real man's bike, I told my mates. A week after buying the Bonnie, I decided to test it out by doing the 100 mile run to Nottingham University.
I'd never done a long trip by bike before and was a bit apprehensive, particularly as it was pouring down and I had a habit of throwing bikes up the road in wet weather. The journey began well but as the engine warmed up the clutch began to drag and I had problems in one traffic jam. No way could I get neutral (trick is to find it before you stop) and I was having to rev the bike to keep the engine running, whilst simultaneously applying the brake to combat clutch drag.
I needn't have bothered; soon as the traffic started moving the damn thing stalled anyway. I arrived at a Godforsaken place called Duffield at the same time as a blizzard and, when braking suddenly, threw the bike up the road in a big way. I was aware of a great pain in my left wrist when I picked the Triumph up.
The bike was ridable - just cosmetic damage really, indicators gone and a bent footrest. I kicked it into life and pulled the clutch in. Ow! That hurt! After stalling it about four times trying to start off and having to let the clutch out prematurely I eventually resorted to mind over matter and forced myself to hold the clutch in until the bike was moving.
Once mobile I used clutchless gearchanges the rest of the way. I parked in the centre of Nottingham and got a taxi to my friend Hawk's digs. After tea and sympathy he drove me to the campus. As it happened the whole weekend was a disaster as my better half was in a foul mood the entire time and I ended up catching the train home as my hand swelled up like a balloon - turned out to be a broken scaphoid so I spent the next six weeks in plaster up to my elbow.
That was a frustrating time with my new bike stuck in Nottingham and me on Merseyside, both wounded. Luckily Hawk had the situation there under control and arranged for a dealer to collect the bike and repair it, so the time wasn't entirely wasted. When I did eventually get the bike back it had been transformed - the controls seemed much lighter and easier to operate, it started first time and ticked over perfectly. Even the clutch worked.
Apparently, it had been way out of tune and the cables had never been oiled since leaving the factory. I gradually got to trust the bike's reliability and in '81 it completed the End to End run without undue hassle (see UMG 19). Later that year a fellow Bonnie owner introduced me to the local Triumph Owner's Club and soon I was a regular at rallies and runs.
To anyone who isn't in a bike club, take my advice and join one - you get more enjoyment from biking when you do it in company. There's also expert (and otherwise) advice on hand - I soon made the acquaintance of a friendly bike mechanic which was handy with my abysmal mechanical knowledge.
In 1982, after I visited the Meriden factory (now turned into a housing estate with roads named after various Triumph models, I think) the bike went through a spell of bad behaviour. It seized a couple of times and the crank sheared, all for no apparent reason. My mechanic crony had a lucrative time.
One incident stands out. After 250 miles of rain the bike stalled and wouldn't restart, so my pillion gave a push. The only problem was that when it started the silly bugger forgot to let go and was dragged along on his knees. I pulled up and looked around, expecting to see him running up to jump back on the pillion, and instead saw him picking himself up off the road with a queue of bemused car drivers looking on!
I got a new job in Leyland, Lancs, in '84. It was 40 miles away and for six months until I bought a house there I commuted daily. With leisure trips I reckoned to average 500 miles a week - not bad for an old Bonnie. Mind you, I give it a full service every month. I wouldn't like to guess what the total mileage the bike's covered in its lifetime would be (speedo/mileometer hasn't worked for many a year) but it must be pretty horrendous.
One day in May '85 I'd been working on the bike in the road opposite my house until dark and couldn't be bothered wheeling it into my back yard. Next morning I went out and there it was - gone! Real sinking feeling inside as I rang up the Old Bill to report it stolen.
Two weeks later it was found in a ditch, looking very sorry for itself. The clocks and ignition switch had been smashed off and the headlight broken, plus the odd dent and scratch here and there. Having said that, it had degenerated into a bit of a rat anyway before the low life pinched it, so I decided to strip it down and do a full restoration.
By this stage in my evolution as a spannerman I could put a motor back together no problem, but I had trouble taking them apart and the bike was in my yard for two years whilst I struggled with seized studs, mounting bolts, etc. Gradually it was transferred, bit by bit, to my spare bedroom for renovation. I did the full works. Frame stoved, new loom, motor rebuilt with new valves, pistons, bearings and bushes. I found the factory parts manual very useful for this type of job. The restoration slowly took shape. As it neared completion we heaved it down stairs for final assembly, adding wheels, mudguards, etc.
In March '88 the great day dawned and we poured some juice in the tank, switched on and kicked it over. It started about the sixth time with three years worth of rust and dead insects splattering out of the exhaust and all over my kitchen. Took a bit of tinkering to get the carbs and timing right but soon I was mobile again.
It felt really strange to be back on the old steed after a three year layoff. The bike didn't seem as smooth as I remembered it, but I had been riding a borrowed VF400 immediately before, so, I suppose, any Brit bike would seem like a boneshaker after that. I went to a couple of Triumph Owners Club rallies that year but the longest run was to the Riders Rights demo in Hyde Park.
That was a scream - 25000 bikers bringing London to a standstill. Later that year I acquired a Cage and the Trumpet began to get a bit neglected, partly because I was now back living with my folks and therefore banned from working on the bike indoors.
My lack of maintenance backfired on me, literally, on a run to Manchester. First, a silencer fell off - I went back for it and strapped it to the rear rack. Further on, overtaking a van, there was a bang, smoke everywhere and sudden loss of power. I noticed the carb inlet balance pipe had come off, allowing a weak mixture to the right-hand pot.
Sure enough, a stripdown later revealed a holed piston. At the time I carried on with one cylinder as we were nearly there and I didn't want to miss the party. I took the whole motor apart to clear out any swarf. Once again, made a few cock ups while dismantling, most of them too embarrassing to mention. Getting the crank out of the cases, I put the whole thing in the oven to loosen off the bearings. Took it out, expecting it to come apart easily but it didn't. I stuck a centre punch in the crank and hit it with a hammer. Bang! End of centre punch broken off and wedged firmly in the crankshaft oilway.
Oh dear, I thought. Turned out mum had got one these new fangled slow burn ovens which never get very hot. Asking around for help, I found a guy at the bike club whose firm possessed a spark eroder machine, only problem was he had to sneak the crank in when his boss wasn't looking and it was about three months before I got it back.
Once I'd collected all the new parts it went back together easily in a few days and has been behaving itself ever since, though the perennial oil leaks are still there. Over the years I've carried out a few mods to make life easier. One is a heavy duty 630 chain and sprocket kit which has doubled the mileage between chain adjustments. Another is fitting a handlebar choke instead of the naff carb mounted item which was always going wrong. A sealed beam headlamp from a Mini will fit straight into the Bonnie's headlight shell, so I buy them from a car breaker to save cash. Also, Mini Cooper brake shoes fit the Lockheed calipers.
In todays' traffic I can still keep up with the commuting hordes okay. I'm usually first away at the lights unless some inadequate wimp with an XR3i or similar decides their fragile ego needs boosting. On the motorway it's a different story - Bonnies don't like them, but then neither do I, so it's no great hardship to avoid them.
Brakes are nothing like as good as the latest Jap stuff but you learn to anticipate well in advance - proof of the risk compensation theory as riding Jap stuff I storm up to obstacles and haul the anchors on at the last minute. The top speed is supposed to be around 110mph, though the fastest I've done on mine is a straight ton. I slowed down out of mechanical sympathy. Average mpg is around 50mpg. I did once get 74mpg by sticking to 3000 revs (50mph in top) everywhere. I'm continually advised to lock the bike away and flog it in ten years time for a fortune, but I'd miss riding it too much.
A lot of people are amazed I've kept the same bike for ten years. However, a basic tenet of philosophy is that change is indicative of unhappiness with the status quo. The fact is, I'm perfectly happy with my Trumpet, so why change it?
Dave Pearson