1977 Triumph Bonneville T140V
A friend from college had owned her for the previous year so I knew both her provenance and his lack of mechanical prowess. He delivered it to Reading from Wales with my girlfriend on the back, the only major problem turning out to be less than perfect ride quality... which I fixed once I'd finished working on the bike, ho ho!
Other issues included non functioning indicators and the ignition switch not working - he'd hotwired it, a scarily simple thing to do. The ride was harsh because of a seized fork leg, due, it seemed, to a manufacturing fault - the chrome on one stanchion had raised lumps in it that I fixed by rubbing it down with wet and dry.
The most annoying problem was low oil pressure. The oil light would start coming on at low revs and as these engines aren't renowned for their longevity it's a good idea to investigate - and sorry to dash hopes but the oil pressure sender is the most reliable bit of the lubrication system. The first time it was the timing side oil seal, a known weak point. The timing cover contains the oil way to the crankshaft, via a cavity into which you carefully slot the end of the crankshaft when you refit the cover. The cavity has an oil seal in it and eventually the lip of the seal wears a deep enough radius on the crankshaft journal to allow the oil to leak past, reducing the pressure to the crank and, especially, the drive side big end. Fix is to strip the engine, machine timing side crankshaft end down 10 thou, then fit a 10 thou oversize oil seal. This worked fine for several thousand miles, in fact until the next rebuild. After that the seal just wouldn't seat properly - in a couple of hundred miles the light would come on, and on inspection the oil seal was always chewed up. Replace seal, all would be fine for the next couple of hundred miles when the light started coming on, again. I eventually discovered it was due to the crankshaft being bent- it was running just out of true, with enough up and down movement to eat the oil seal. Possibly due to me dropping it when I was starting the previous rebuild...
Yes, in retrospect the work I did on the bike didn't always go smoothly or to plan. I managed to cross thread the gearbox mainshaft, meaning I needed a new nut every time I had to remove the clutch, the exhausts would never seat properly in the cylinder head, the end of the tacho drive unit was sealed with a 1p piece and Araldite (actually that worked well), and until I put on the Boyer she ran on second-hand coils from a Kawasaki 650, chosen because they were the right physical size, though clearly the wrong specification as she'd only kick or bump start if the battery was fully charged. So by the late 1990's she was getting a bit ratty and I wasn't using her much, having discovered the joys of my first Ducati and Hinkley Triumphs. But I never considered selling her (I've lost count of the number of times some old codger's come up to tell me how much he'd regretted selling his Triumph for tuppence three farthing in 1960something). So, in late 1999 with an indicated 48,000 miles on the clock, I decided to treat her to a total professional rebuild.
This I entrusted to my local Triumph garage, Rockerbox in Farnham, (+44 (0)1252 722973) asking them to strip the engine and gearbox, replace anything worn beyond service limits, balance the crankshaft and do any sensible upgrades thought prudent. They went through the motor with a fine tooth comb and, unsurprisingly, announced just about everything to be worn out - so cams, bearings, seals, valves, pistons and barrels and more were all replaced and a high capacity oil pump added; about the only original bits left are the crankcases and engine mounting bolts. The job cost roughly as much as the bike is worth, and I still consider it a bargain!
She's only done a couple of thousand miles since (long gone are the ‘ride her every day' days), I keep the revs (mostly) no higher than 4,000, about 70mph in top, and so far she's shown no sign of blowing up. Handling is still OK and on twisty A roads that, and the acceleration to 70, is good enough to embarrass quite a few much younger sports 600. And even parked up I still reckon she's one of the best looking Bonnevilles ever. My favourite.
Which freed it up a treat, trouble now was the fork seal wouldn't, err, seal. This I sorted by installing some ‘everlasting' fork seals - rather than being wedged into the legs they float in them, the pressure of the oil forcing them out and tight as the forks are compressed. They were my last resort before forking out for a new stanchion, and somewhat to my surprise they actually worked, and do so to this day. The electrical problems were easier to fix - just taping up bare wires and improvising with a bit of tin in the indicator switch solved them all.
She came to me as US spec, high bars
and an unfeasibly small tank - range about 100 miles. And less than 10
miles on reserve, as I discovered the first time I had to use it. Records
say she was sold direct into the UK and I've no idea if she left the factory
with the US bars, cables and tank, but despite the impracticality I find
the looks appealing (these days she out poses Harleys). The tank range
isn't a disaster - we toured two up around northern Scotland and did a
2,000 mile tour around Sweden, never having to panic about fuel. And neither
time did she let us down - a flat battery and a broken speedo cable were
the only problems on either trip. Mind you, the broken speedo cable nearly
wrecked the Swedish trip. We were pulled coming out of some little town
on a clear and empty road and got written a ticket for doing 79kph in
a 40kph limit. Not best pleased I was relating the story to the people
we were staying with, who congratulated me on my good luck. I questioned
their concept of ‘good luck', and they explained that Swedish speeding
penalties came in three tiers - a fixed fine for up to 20kph over, a bigger
one for up to 40kph over... and 21 days in clink for any higher speeds.
Other than that I've never been done for speeding or any other infraction
on her. After the flat battery experience I rewired the lights through
the ignition (main and parking lights were directly wired to the battery
when I got her, which I think was standard). A bonus was the rear bulb
unit being rubber mounted as a (surprisingly effective) counter to the
ferocious vibration; this means it has a dedicated earth lead, so I took
the opportunity to extend and run it through the three way light switch,
in place of the parking light, itself even less use than as standard now
it needed the ignition to work. Sacrificing the parking light for a rear
and brake light cut-out was a good trade-off - very useful for those occasions
when I needed to disappear quickly.
I was in my mid twenties when I got her and did a lot of miles in the
first ten or so years - I had a Honda 400/4 as well (which had about the
same performance as the Bonneville) and a Laverda
Mirage for about 6 months until I wrote her off, but the Bonnie was
always my favourite (and still is). She handles OK (ground clearance could
be better), lots of low down torque and with peashooter pipes in place
of the standard ‘cigar' silencers she makes a lovely noise. Instrumentation
is good (check out the cute NVT badged speedo and tacho by panning the
image below), front light accepts a halogen reflector and bulb, the indicators
work well and are a must for modern traffic. Left foot gear change means
no acclimatisation issues when I switch to and from more modern machinery.
Overall she's a good mixture of traditional character and modern convenience.
The main weakness (other than the prehistoric design) was the rear wheel
- spokes kept breaking. This was obviously recognised as a problem by
Triumph because the later T140E models had heavier gauge spokes. The first
step I took from keeping her ‘standard' was to replace that wheel
with one from a T140E, and presto, no more breaking spokes. The other
significant change, though stupidly not made until I'd had her for many
years, was to install a Boyer Bransden electronic ignition. It transformed
the running - I'd spend an hour or so setting up the old contact breakers
and she'd run great once I'd tightened the various bolts... but in a hundred
miles she'd be vibey, take more than two kicks to start and not tick over
cleanly. The Boyer is truly fit and forget and gives a reliable 900 rpm
tick over. Other sensible stuff I've done is fit an external oil filter
and a Norman Hyde oil cooler. The former hangs discreetly down from the
oil tank in front of the rear wheel, the latter mounts between the two
front down tubes and looks pretty neat. Other than the obvious advantages
these give - cooler, cleaner oil - they also up the overall capacity by
about half a pint, which is significant given she only holds about 4 pints
as standard.
She did go wrong pretty frequently though, largely due to the whole bike
being overstressed - during high speed use she'd vibrate like a jack hammer,
great for female pillions but
not for the engine or ancillaries. So she taught me a lot about rebuilding
engines. Well, tried. Head gasket
blowing between the two barrels stranded me once - she'd suddenly gone
down a bit on performance then wouldn't start after I'd stopped for fuel,
annoying but not too difficult to fix once home.
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