The magazine for classic Japanese motorcycles

Benelli 500 LS

Selwyn Stickler is fed up with people telling him that his Benelli is just an Italian copy of a Honda CB500. “Look,” he says, “Benelli didn’t need to copy Honda to make a four. They were racing a 250cc inline four back in 1939 and what’s more, it was liquid-cooled, supercharged and produced 52bhp at 10,000rpm. That was eight years before Soichiro Honda bolted a 50cc two-stroke generator engine to a bicycle frame, and 20 years before the first Japanese four-cylinder motorcycle. Who copied who?”

Of course, Selwyn is right. The Italians have a long history of making four-cylinder motorcycles. When Benelli announced in 1960 that it had built a four-cylinder 250, some thought even that was an inferior copy of the RC160 which Honda had introduced a year earlier. But come on – who believes that Benelli’s technicians ever got the chance to look inside an RC Honda?

Designed by Savelli, the racing air-cooled Benelli four used a 44mm bore (just like the RC160) and featured double overhead camshafts driven by a train of gears between the centre cylinders. A geared primary drive ran on the left side, between the first and second cylinders, with a six speed cluster and dry clutch. Although the Honda had 16 valves, the Benelli made do with eight but that didn’t stop it spinning to 13,000rpm and developing 40bhp.

It was nearly two years before the Benelli made its race debut. Then in an early season warm-up, before the first GP of 1962, Grassetti beat Jim Redman and Tom Phillis on their works Honda fours at Cesantico, a circuit on the Adriatic coast about 40 miles from the Benelli factory at Pesaro. Things were looking even better when new signing Provini beat Redman by a healthy 22 seconds after 33 laps of Montjuich Park’s twisty track to take the Spanish GP, with Phil Read and the disc-valve RD56 half a minute behind the Honda.

Although the Benelli factory was cash-strapped, development continued and by 1965 the 250 racer featured a shorter, lower and lighter chassis, a seven-speed gearbox, American-made disc brakes (soon changed back to Italian drums) and a power hike to 52bhp at 16,000rpm. Provini won every race in that year’s Italian national championship but the highlight of the season was when he won a rain-soaked Italian GP at Monza, although with 11 rounds already run Phil Read had delivered the 250 title to Yamaha with seven wins.

There was a new 343cc version with four valves per cylinder for 1966, and for 1967 a 500 class bike was made by boring and stroking the smaller engine to give 414cc. Both engines were revised for 1971 with inclined cylinders, shorter strokes and capacities closer to the full size. The 350 was fast – Pasolini was timed at 152.5mph through the speed trap at the Isle of Man TT, the same as the MV triple – and he ended the season runner-up behind Agostini in the world championship series. Australian Kel Carruthers took over the 250 Benelli and won the 1969 world championship ahead of a string of screaming Suzuki, Yamaha and Ossa two-strokes – the last time the title would be won with a four-stroke.

But the Pesaro factory was in deep financial trouble, and struggling to make a profit from the 643cc vertical twin Tornado and four-stroke 250 singles with horizontal engines. In 1971 the company was bought by the Argentinean racing car driver and supercar designer Alejandro de Tomaso, who decided to update the Benelli range with a new four and also a six.

Benelli’s long-time designer Piero Prampolini wanted to design engines based on the racers, but de Tomaso put the brakes on that idea as it would have been too expensive so Prampolini had a good look at the single overhead camshaft CB500, which had been introduced that year. First he designed the 750cc Sei (Six). The prototype caused quite a stir at the 1972 Milan show – after all, this was six years before Honda came up with the CBX.

The production Benelli Quattro (Four) debuted for the 1975 model year with the same chassis as the Sei and bodywork designed by Ghia, the styling company also owned by de Tomaso.

While the CB500’s barrels sat vertically on the crankcase, the Quattro’s were tilted slightly forward to give a more rakish look. Power output was claimed at 55hp, substantially up on the CB500, but whereas the Honda had a disc front brake the Benelli had a twin leading shoe 230mm drum. That was soon replaced with a single Brembo disc, and later twin discs.

With 49 horses the LS version (Light Sport) of 1977 was not as powerful as the Quattro, but the engine was more flexible and the frame was shorter and lower. The LS was also 25kg lighter.

For 1979 there was another new version – the 504 Sport which wore a bikini fairing from the MkI Guzzi Le Mans (the name did not refer to a capacity increase but 50 centilitres, four cylinders). There was also a 350cc Benelli four and a 604cc version with 654 badges. Production of these fours ended in 1988. There was also a 254 Quattro introduced in 1976, but the 231cc engine was completely different.

Prampolini may have had a good look at the CB500 – but he did not copy it. Yes, it has the same bore and stroke dimensions of 56 x 50.6mm and a single overhead camshaft, but there are subtle differences. The Honda has a compression ratio of 9:1 while the Benelli runs with low-domed pistons to give 10.2:1. Benelli rings are narrower, and the piston with rings and pin weighs only 166g compared to the Honda’s 180g. Honda connecting rods weigh 320g, 40g more than the Italian ones, and the big end shells are completely different. The Benelli camchain is heavy-duty and with a different pitch. The valves may be the same size, but the Benelli ones have waisted stems and the collet grooves are higher on the stem. Fit Honda valves in a Benelli and, thanks to the high-lift cams, the valve collets will hit the valve guides – with disastrous consequences.

More obvious differences are the Bosch generator on the crankshaft, and the Bosch starter motor mounted behind the cylinders. Carburettors are 22mm VHB Dell’Orto. The original five-speed Quattro had three dogs on the gear cogs, but this was soon changed to six dogs. That made slick changes difficult, so by the time the LS version was introduced there was a new gearbox with five dogs on the cogs.

The alternator is on the left of the crankshaft, while two sets of ignition contact breaker points are hidden under the round cover on the right. Each set of points supplies the sparks to two pots simultaneously, so one spark is wasted. “You can fit a Honda ignition points cover,” agrees Selwyn, “but the logo would be about 30 degrees off horizontal. You can also fit one from a Suzuki or a Kawasaki – they all have 115mm centres between the screw holes!” Other bodges would be to fit a CB500 gearbox sprocket, but the mainshaft splines are slightly smaller on the Benelli. “The sprocket will rattle and knacker the mainshaft,” warns Selwyn.

If you check out the specification of the Benelli you could be fooled into thinking that it is just an Italian version of the UJM – that’s Universal Japanese Motorcycle. But facts and figures don’t tell you everything you need to know.

While the engine might look like a Honda, the chassis and ride feel decidedly Italian. Steering is pin sharp and always accurate, thanks to a frame that is sturdier and suspension that is firmer. Earlier versions of the Benelli four used Marzocchi forks but those on this original finish 1981 LS are Benelli’s own, made in the Moto Guzzi factory, which was also owned by Tomaso. They are damped and sprung lightly enough to soak up the bumps but firm enough not to dive under hard braking – and with twin 260mm Brembo discs to squeeze the speed the Italian job stops a lot quicker than a CB Honda. The Marzocchi rear shocks have five preload settings, but for my weight the middle notch was perfect. That short wheelbase, sharp steering angle and low centre of gravity make for nimble handling, and the Benelli can be flicked from side to side effortlessly with complete confidence.

To get the best from the Benelli you have to rev it, but that is not difficult as the needle swings into the red zone remarkably quickly. There is pulling power from 2000rpm but when you get the engine on the boil the Benelli sings like Pavarotti. Keep it between 6000 and 9000rpm and really enjoy the ride. The engine has a harder edge than a CB500, which feels as mild as a pussycat in comparison. Top speed is about 105mph, and you can cruise effortlessly at 90mph, but this bike was designed for charging through bends not humming along motorways.

Of course, by 1981 Japanese manufacturers had moved on and were offering DOHC engines with three- or four-valve heads, and improved chassis. The CB500 and the Benelli were from a different generation.

De Tomaso had saved the Italian motorcycle industry. Besides rescuing Benelli and Guzzi he also convinced the Italian government to ban the import of sub-350cc motorcycles, and to hit large capacity foreign bikes with a hefty sales tax to give other home market manufacturers a chance. He knew that Italian motorcycles were too expensive – a 500 Benelli cost 25% more than a Japanese four. That was down to high labour costs and, as de Tomaso pointed out, a Japanese worked 23,000 hours a year compared to only 15,000 hours for an Italian. Unfortunately for Benelli, there weren’t enough motorcycle riders out there who were prepared to keep subsidising Italian workers, so Benelli sold far fewer motorcycles than Honda. Today you can pick up a very nice Benelli four for around £3000 – which means that the Italian job still costs more than a CB500.