|
Benelli 504 Sport

|
Make Model |
Benelli 504 Sport |
|
Year |
1980 |
|
Engine |
Air cooled, four stroke, transverse four
cylinders |
|
Capacity |
498 |
|
Bore x Stroke |
56 x 50.6 mm |
|
Compression Ratio |
10.2:1 |
|
Induction |
4x 22mm Dell'Orto carbs |
|
Ignition /
Starting |
|
|
Max Power |
52 hp @ 8600 rpm |
|
Max Torque |
31.5 lbs @ 7400 rpm |
|
Transmission /
Drive |
5 Speed / chain |
|
Front Suspension |
Telescopic forks |
|
Rear Suspension |
Pivoted rear fork 5-way spring preload |
|
Front Brakes |
2x 260mm discs |
|
Rear Brakes |
Single 260mm disc |
|
Front Tyre |
3.00 S18 |
|
Rear Tyre |
3.50 S18 |
|
Dry-Weight |
168 kg |
|
Fuel Capacity |
15.5 Litres |
|
Consumption average |
49.5 mp/g |
|
Standing
¼ Mile |
14.4 sec / 90 mp/h |
|
Top Speed |
106.5 mph |
|
Overview |
Bike review |

Rumour holds that the old Honda CB500 four engine
will fit straight into the Benelli 504's chassis. I don't know how true this is
despite having owned a CB500 a long time ago. The engines do look similar and
their power output is equally bland. The 500cc OHC across the frame four claims
50 horses but its delivery is so linear that it seems a lot less, there's never
the feel of a motor coming on cam. Just like the old Honda, it'll put 80 to
85mph on the clock without any undue abuse, but going any faster is such hard
work it's really not worth the bother.
The engine responded to juvenile tacho excess by
needing valve adjustments every 500 to 750 miles and putting out a flurry of
secondary vibes through not just the pegs and bars but also the seat and tank.
The carbs kept their balance for about 500 miles and every now and again one of
the slides stuck, which made the engine hunt between 1000 and 5000 revs!
Carburation always seemed slightly hesitant, a
distinct delay between whacking open the throttle and the back wheel doing
something. Its relatively primitive nature showed up in fuel that was never
better than 40mpg. The dynamics of carburation, exhaust and combustion chamber
shape were shown up when riding the 504 into a strong headwind; speed was down
to 70mph and fuel up to 35mpg!
The motor always felt revvy as well, I was often
trying to change up another gear when I was already in top. I could never
persuade the Benelli to adopt a relaxed pace to match the parameters of its
performance and chassis. The gearbox, with more than 15000 miles done, was
neither slick nor precise; it mirrored, in fact, some old sixties Honda hack in
its application. It was not impossible to adapt to, but even then would serve up
a false neutral, which buzzed the motor like its poor old heart was going to
explode into a million pieces.
The double cradle loop frame could have been
produced by any factory anywhere in the world, but was well enough thought out
to save the bike even when it was slung into desperate conditions by a sudden
false neutral. The whole beast was held in check by famously stiff Italian
suspension at both ends. The forks, despite their mileage still suffered from
some seizing and responded to slow speed holes by sending concentrated jolts
straight up my arms. The shocks did the same trick to my spine.
Smooth roads held no terrors for the Benelli, it
could be slung over on to the stand prongs without the Pirelli tyres giving a
moment's worry. The 504 had 425lbs of mass and slow steering geometry against it
in the curves, but its stability and neutrality allowed me to take outrageous
risks when I was in the mood.
This stability held it in good stead on bumpy
roads. The rider took a battering but the wheels held on to their line in a way
that the old Honda four could never hope to emulate - it used to waddle about on
soft suspension, zig-zaging from bump to bump. As the Benelli never accelerated
hard nor went very fast, any test of the chassis was limited but, apart from the
lack of bump absorption, I was at ease with the 504.
Which is more than can be said for the drive
chain. It always wanted to dissociate itself from the chassis, wore at an
astonishing rate and broke three times when I tried to run them after removing
links. They barely lasted 4000 miles. One time the broken chain busted into the
back of the crankcases but I repaired that in-situ with good old Plastic Metal.
The only other chassis horror was the way
corrosion would suddenly appear from nowhere, spread like wildfire until the
whole component was covered in gunge. The frame, wheels and exhaust were
particularly susceptible. The front disc calipers followed the trend set by the
Japanese of seizing up over the winter, but they were easily rebuilt. Pads
lasted 8 to 10,000 miles a set.
After a year's riding, various electrical
components decided they couldn't take extended exposure to the English weather.
Switches that filled with water, corroding contacts, made for amusing incidents
such as the indicators flicking on and off in a psychedelic manner whilst the
horn, normally nothing more than a croak, blared harshly enough to have
pedestrians waving their fists in anger. The fuses either rusted to death, fell
out or exploded.
By the time I was able to find the energy to
rewire the bike, the generator was burnt out, the rectifier had melted, the
battery was devoid of acid and just about every other electrical component had
to be replaced. The breakers provided a viable source of electrical components,
although I stayed clear of Suzuki bits. The most difficult part was persuading
someone to rewind the generator but fifty notes in the right hands solved that
one.
As the bike had to be stripped of all its cycle
parts to access the electrical bits I took the time to rust proof and then
Hammerite the frame. Some Scientific Coating's clear liquid was put on polished
wheels, which meant that rather than a two hour cleaning session a week a quick
wipe with a rag was all that was needed to keep them neat. A Honda CB500/4 four
into one exhaust (thirty notes secondhand) was persuaded on to the Benelli
engine but needed a bit of a pounding to clear the lower frame rails. It sounds
lovely, but didn't increase performance.
Other complaints that could be levelled at the
Benelli included a pathetic seat that went hard after 50 miles, wheels bearings
that needed replacing every 6000 miles and a petrol tank that even when newish
loved to rust rapidly - I'm on my third, one of them actually dropped a load of
fuel over the engine. The bike sizzled for a while but resisted the urge to
explode.
The Benelli was quite resistant to crash damage,
as long as engine bars protected the ends of the crankshaft, the demise of
either extremely expensive. I've slid off on diesel a couple of times, did no
more damage than batter the pegs and bars. More serious was smacking into the
side of a car that shot out of a road so fast it could only have done so with
the sole intention of trying to kill me.
The front end hit the car, the sudden loss of
momentum causing me to somersault over the cage, roll down the road a few yards
and then pick myself up. I was full of craziness by then and would've torn the
driver limb from limb, but the impact of the crash had warped the car's body so
that none of the doors would open. There was a strong smell of petrol, so I
tried to pull the Benelli out of the car with the intention of throwing a
lighted match on the cage once we were at a safe distance.
Fortunately for the cager, there was no way I
could pull the bike out. Someone had phoned the police so there was no hope of
physical retribution. When the bike was finally pulled free, damage consisted of
bent forks and dented exhaust, along with a bit of cosmetic damage. The cast
front wheel was still intact. His car looked a write-off so I decided not to
inform my insurance company which would stop his claim dead.
I had the forks straightened for £30 and cut and
welded the pipes - they look a bit naff but matt black paint hides most of the
damage. The smashed clock was glued back together with Superglue, as was one of
the indicator lenses. This may sound dodgy but I've found it works fine from
past experience.
This crash occurred about three years and 12000
miles into my ownership (the clock read 19,650 miles). The only result of the
damage was fork seals that didn't last for more than 5000 miles (I hadn't had to
replace them before). There was so little suspension movement that the lack of
damping that resulted wasn't too noticeable.
Handling became more alarming when the rear
shocks lost all their damping (at about 23000 miles). The back wheel would try
to career off the road whenever I leant the bike over more than a few degrees on
bumpy roads. It'll also jerk around after hitting a pot-hole. That was easily
sorted with a pair of rather more compliant Konis. My spine was thankful for the
diminution in violence of the bumps that got through the chassis. A slight weave
occurred at 90mph, but this speed was never sustained for more than a few
seconds so the weave had no chance of developing into a wobble.
A cheap rack and massive top-box were added for a
while, but that did upset the handling whenever any kind of mass was put in the
box. It didn't feel safe above 60mph. One blustery day, the wind shook the back
end so much I thought the swinging arm bearings were shot, but it was just the
gale catching the plastic. In the end I dumped the top-box.
That didn't help the touring ability. The shape
of the tank meant that tank-bags slithered around all over the place, usually
ending held in place by nothing more than its own weight and my knees. The only
safe place to carry luggage was on the pillion perch. Once I had a bungee cord
snap, wrap around the rear wheel whilst my clothes were scattered half a mile
down the road. I never knew that bungee cords could be stretched so thin.
Touring the bike could manage, but only 150 to
200 miles a day. Any more then it became very uncomfortable and somewhat
enervating (from the vibes and revvy nature of the engine). Fuel, engine
maintenance and chain wear were other variables that didn't inspire during long
distance usage but the basic reliability of the engine meant I had every
confidence in reaching my destination.
Some Benelli motors don't last very long (I've
just brought a dead 504 with only 14000 on the clock) but mine has now done
33000 miles without any major problems except for frequent doses of tender
loving care. I suspect that is the determining factor in durability, neglected
bikes both rusting and seizing quicker than most. Spares are so rare that it
pays to track down one of the non-runners. Rarity of the 504 makes that hard
work.
Prices are hard to work out. There's always the
odd jerk who thinks because it's rare and Italian it must be a classic worth
thousands, but I bought my nice one for £450 and the non-runner for £95. That
sounds about right for a machine that's slow, quick corrode and heavy on
consumables. I like its looks but can't claim it approaches beauty. It runs well
in town, for short blasts in the country and for moderate touring. As a cheap
and cheerful all-rounder it makes the grade, as a future classic my money's on
the CB500/4!
Source .umgweb.com
|