Owning both a late T140 750 Bonnie and a BMW R80/7 might seem like a
strange choice but there's nowt so queer as folk... Both bikes were accidental
purchases. I just happened to be flicking through the ad's in MCN, as you
do, when I saw the Bonnie. A runner needing an MOT for £600. I was
in two minds. It was cheap enough but my past experiences of British bikes
weren't too enjoyable. I tossed a coin and hit the phone.
The owner's command of English didn't go beyond grunting. After half
a dozen attempts I had the address. I tossed the coin again and cursed.
The bike turned out to be more together than the owner. Had electronic ignition,
a sweet sounding pair of sixties silencers and didn't drop any oil. The
chassis was a little battered and rust sprouted from shock springs, the
odd bits of chrome and the chassis. Nothing that looked like it was going
to collapse, though. I offered £500, the owner grunted and the deed
was done.
Having arrived on the BMW, I then had the problem of getting two bikes
home. In the end, I let the past owner ride the Triumph and gave him a lift
back. It was immediately evident that he only had a minor grasp of clutch/gearbox
coordination. Or the transmission was shot...I had another blast but it
was smooth and precise under my control, but then I'd become used to the
BMW's clunk-click, half a foot lurches and a rising rear end that could
go wild enough to give me a good kicking in the kidneys. In contrast, the
Triumph's gearbox was a paragon of virtue, a perfection of engineering,
etc.
This was the immediate difference between the machines. The next was
ease of handling. Here, the Triumph won out again, being lighter, narrower
and easier turning. It was also more stable at 70mph plus speeds and didn't
mind if I changed my mind half way through a bend. Where a change of line
on the BMW involved a good chance of riding off the road, the Triumph only
objected when it ran out of ground clearance, with the stands digging in
ferociously. Rather odd, that the Beemer, with those bloody big jugs sticking
out, could be thrown over as far as the Triumph, until I'd modded the stands.
The BMW won out on long tours. Not only was the Triumph's riding position
rather odd - neither comfortable in town nor on the open road - but the
engine buzzed out the vibes at 80mph where the BMW smoothed out and had
a most relaxing stance. The taut, short travel suspension on the Triumph
rumbled a little even on smooth motorways whereas the BMW's tuned out all
but the most vicious of road shocks.
Everything about the BMW - its general build quality, the size of its
fuel tank, its history, etc - gave the impression of being able to eat up
huge mileages without any worries whatsoever. Whereas everything about the
Triumph was against it, its reputation, vibration and build quality made
me think twice before slinging a leg over the bike and heading off into
the sunset. This is unfair to Triumph twins, I soon learnt that it all depended
on how well they'd been rebuilt and how well they were treated.
After cleaning up the Triumph's chassis, polishing to a reasonable sheen,
I couldn't find much wrong with the OHV twin. Despite its owner's lack of
competence - he probably hadn't touched it and therefore done no serious
damage. The mileage on the clock was only 18,000, compared to 74,000 miles
on the BMW, but the Triumph had six past owners! Either the clock was lying
or the owners hadn't been keen on riding any distance.
One reason for that was the size of the engine. 750cc's of straightforward
vertical twin engineering equals loads of vibration and potential hassle.
It's an old song, if you want simplicity, narrowness and lightness then
these old style twins are ideal. But the price paid is omnipresent vibration
as the complete lack of primary balance - basically two cylinders pounding
up and down side by side - is only mitigated to a degree by careful matching
of the frame dynamics to the engine's characteristics.
The Beemer doesn't actually vibrate as in putting out a buzz but it does
rumble at high revs and shakes in the frame at low revs. 40 to 100mph, though,
it smooths out very nicely, more a suggestion of the engine working away
than the nasty thrumming put out by the Triumph above 75mph. Come 90mph,
a serious stiff upper lip was needed to survive but it seemed to smooth
out slightly at 100-105mph before going into an absolute frenzy. Its smoothest
range was 55 to 70mph whilst the best power delivery was from 65 to 90mph
(non-standard exhausts and air-filter, stock bikes are somewhat more somnolent).
Up to 90mph, the Triumph was the faster accelerating of the two, helped
along by being able to snick up the gearchange at a rapid rate rather than
the clunk-pray-click-swear-clunk on the BMW, but I had little inclination
to hold a decent velocity on the Triumph. A continuous 70mph trawl was about
all I'd want to do - boring and not particularly comfortable.
Much more fun on the back roads, though, as it could be hurled through
the bends and slung around to my heart's content - so much fun that the
vibes faded into the background. The Beemer wasn't bad once used to its
ways - it wasn't the kind of machine to sling a leg over and let rip with
the throttle without any thought as to how it should be handled. Very careful
throttle work needed to make sure it didn't turn into a rocking horse, no
way it would easily change from the selected route.
It takes a good 2000 miles to become used to the BMW's ways. Once re-educated
by the Bavarian beast, it could be ridden in a fast, fluid manner that was
so relentless that despite its lack of sporty specification would cover
distances more rapidly than most bikes. The further you wanted to go the
better the BMW became.
A pattern soon emerged. If I wanted some fun, a short hack through the
country lanes or A-road hustle, then the Triumph was the natural choice.
Any kind of serious distance, the BMW was the only option worth considering.
Both did around 60mpg, needed an eye kept on the oil level and felt safe
on wet roads. The BMW needed its valves done every 2000 miles, much easier
to get at than the Triumph's which wanted attention every 400-500 miles.
Carb balancing was another matter, the BMW's needing a fiddle every 250
miles (obviously a bit worn, ignore them and the engine would try to shake
itself out of the frame at low revs). The Triumph's would last for 500-600
miles but took twice as long to set up. Also the Triumph's chain was a major
pain, needing attention every couple of hundred miles. I'd forgotten how
much hassle they were after the BMW's shaft.
I've done 9000 miles on the Triumph without any major hassles, suggesting
that at some point it'd had a good rebuild. Overall, I've done 68000 miles
on the BMW with just the regular servicing but I tend to ride it in its
optimum speed range and never really thrash the engine - it just doesn't
feel right. I doubt if the Triumph will do that kind of mileage without
several expensive rebuilds, especially as I like to rev it out in the tighter
curves. Already, from cold there's a disturbing ringing noise from the top
end!
If I could have the BMW's long-legged nature in the Triumph's form factor
without any of the vibration, the perfect bike would emerge! Unfortunately,
I can't. I must say that the Bonnie was bargain priced - a good R80 going
for three times that - and any time I want to sell it I won't have any problem
making a nice profit. Spares are readily available for both models, the
Triumph stuff cheaper but of a somewhat variable build quality - one guy
I know had terrible problems with pattern valves and springs! I'm quite
happy to keep both for a while; a nice contrast in motorcycling experiences.
Terry Osborne