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Archives: Italian Masterpiece

 

The 250cc Benelli G.P. racer on display at the Birdwood Mill National Motor Museum in the late 1980’s

It was in the mid-1970’s that I first stumbled across the exotic little Benelli 250cc GP bike.  I’d made my usual pilgrimage to South Australia’s motorcycling mecca, which at that time was Adelaide’s Pirie Street, where I spotted the green and silver racer.  It was prominently displayed in the doorway of one of the many motorcycle shops that had come and gone over the years and whose name now eludes me.  The price tag tied to the alloy clip-on handlebar said $3,200, which seemed a lot considering I’d paid “only” $1,800 for a new Z1 900 Kawasaki, although I had no idea at the time of how rare the Benelli was.

My second encounter was some years later during a visit to South Australia’s Birdwood Mill National Motor Museum, nestled in the Adelaide Hills.  Taking pride of place in the motorcycle display was the Benelli, but more surprising was a sign declaring it to be Australian Kel Carruthers’ 1969 250cc World Championship winning bike!

Over the years since that second chance meeting I’ve found the idea of a rare “works” racer – and a world championship winning one at that – finding its way into an Adelaide motorcycle shop extremely intriguing.

With my curiosity finally getting the better of me I decided to ring Jon Chittleborough, the curator of the motor museum, with the intention of putting together an article on the said GP racer.  Jon confirmed that the bike was still on display at the museum and that I was quite welcome to come along and photograph it.  But since becoming curator, he had been unable to confirm if the Benelli was, in fact, Carruthers’ championship winning bike as its past was somewhat foggy.

A masterpiece.

  A masterpiece.

But before we go any further a brief description of the 250 fours, evolution is perhaps called for.   It was in mid-1960’s that Giovanni Benelli and Ing Savelli introduced an entirely new design four-cylinder 250cc GP machine that would eventually replace their ageing D.O.H.C. single.  In true fifties’ style the prototypes chassis was rather bulky and over-engineered, while on the other hand, the rim sizes were a narrow 2.590 x 18 front, with a matching 2.75 section rear.  The engine was a dry sump design with vertical cylinders, double-overhead camshafts and two valves per cylinder.  Bore and stroke measured 44 x 40.6mm for a capacity of 246.8cc, which was retained up to Carruthers’ world title-winner.  Benelli claimed 122kg (268lb) dry weight for the bike and 40bhp at 13,000rpm, which compared quite well with the contemporary Honda of the day.

Benelli continued to rely on an updated version of their D.O.H.C. single during 1961 while they refined the untried four, so it was not until 1962 that the Benelli made its racing debut in the hands of works rider Silvio Grassetti.  Many changes had been made to the machine since its first appearance, mainly the removal of the oil tank from under the seat in favour of a large-capacity bolt-on sump with a two-way pump mounted above it, and running off the camshaft drive pinion.  Ignition on the prototype had been by battery and four coils with the points driven off the end of the inlet camshaft.  This system had proved unsuitable as the four-lobe contact-breaker points tended to float at high rpm effectively reducing the engines ability to reach maximum revs.  A Lucas magneto was installed on the right front side of the crankcase and bevel-driven of the camshaft pinion, which also had the desirable effect of reducing weight. The chassis was also partly redesigned and slightly wider sections tyres fitted.

The Lucas magneto fitted to the earlier model of the 250cc GP racer.

The Lucas magneto fitted to the earlier model of the 250cc GP racer.

1964 saw the great Italian rider Tarquinio Provini join the team.  He had been runner-up in the previous year’s title riding a supposedly obsolete Morini single, only losing out at the last round in Japan to Jim Redman’s Honda four after each had won four races apiece.   The former two times world champions influence at Benelli was soon apparent with the factory completely redeveloping the bike.

The frame was made smaller and lighter helping to bring the overall weight down to 112kg (264lb) dry.  New camshafts were installed which raised the rev limit and narrowed the power-band giving 48bhp 14,500rpm.  To compensate for this, a seven-speed gearbox replaced the original six-speed unit.  Two pairs of 20mm Dell’Orto’s provided Carburation with a single flat-sided float bowl between each pair.  Provini was the first to reap the rewards of these changes by defeating the Honda, Suzuki and Yamaha factory teams at the opening European GP held in Barcelona’s Montjuich Park, although the rest of the season only produced fourth and two-fifth places respectively.

More alterations were made for 1965, with modified inlet and exhaust ports for better breathing, and new camshafts offering greater lift and dwell.  Combustion chambers and piston crowns were given more squish area, while more substantial 24mm carburettors were fitted with specially tuned bell-mouths that gave an extra 2bhp.  Usable power now started at 8,500rpm and lasted to 14,500rpm at which point it was producing 52bhp.  However, the most significant change came in the form of a new magneto from a Mercury two-stroke outboard motor, modified for four-stroke use.  The Lucas unit had been initially designed for the lower revving 350, and 500 fours produced by Gilera and MV in the 1950’s and proved unreliable when engine speeds went over 12,000rpm.  The American made unit solved the problem and was retained to the end of the model’s development, although some experimentation was done with an early form of electronic ignition.

Beautiful sand-cast engine cases.

 Beautiful sand-cast engine cases.

The chassis was also modified for 1965, being lowered and shortened even more, and equipped for the first time with disc brakes.  Benelli was one of the first in GP racing to adopt this now universal feature.  Unfortunately, the US made Airheart disc brakes were designed initially for go-kart use, and this, plus a lack of brake pad choice, resulted in the twin 7in discs being insufficient to stop a 112kg motorcycle at 143mph, which the Benelli was by then was capable of.  By the end of the season, the team had reverted to drum brakes all round, especially after suffering braking problems in the pouring rain during the Italian GP at Monza, which nonetheless did not stop Provini winning convincingly by lapping every other finisher on the Italian four.

Meanwhile, the desperate struggle for supremacy in the 250cc class raged between Honda and Yamaha, accelerating development of their race bikes.  Honda’s 250cc six-cylinder was now producing 60bhp and starting to handle thanks to the talents of Mike Hailwood.  Benelli had to do something if they were not to be left behind.

Ing Savelli’s answer was to introduce a stop-gap model in the winter of 65/66 with three valves per cylinder, using two inlet and one exhaust.  This helped to increase bottom-end torque but not top-end power, so inevitably a leaf was taken out of Honda’s book, and four valves per cylinder were adopted.  This narrowed the power band again but increased maximum safe revs to 16,000 and boosted the engine’s output to 55bhp.  It was on this machine, now painted slate grey instead of Benelli’s more colourful green, that Provini won their third consecutive Italian national title but failed to make any impression on the Japanese bikes in the Grands Prix.  Then tragically, while practising for the 1966 TT at the Isle of Man, Provini crashed and seriously injured his back ending a great racing career.

This was a severe blow to Benelli, but they decided to continue on and enlisted Aermacchi rider Renzo Pasolini for 1967, although it was not until 1968 that he started to show his full potential on the 250 by winning the Italian title and coming second in the TT.  By 1969 both Honda, Suzuki and Yamaha had withdrawn from GP racing giving Benelli perhaps their best chance at the title.  Pasolini proved as much by winning all seven races of the keenly contested Italian season-openers and was the pundits choice for the world championship.  Sadly, he crashed in practice for the second GP at Hockenheim and was injured seriously enough to miss the first three GP’s, including the important Isle of Man TT.

The Bennelli has a purposeful look.

The Benelli has a purposeful look.

The Spanish Ossa factories remarkable monocoque two-stroke single, in the hands of Santiago Herrero, easily led the championship, forcing Benelli team manager Nardi Dei to enlist the services of reigning world champion Phil Read and privateer Aussie Kel Carruthers’ for the TT.  Read retired during the race, but Carruthers’ swept to victory more than three minutes ahead of Frank Perris’ Suzuki.

Kel was rewarded with a place on the team for the rest of the season even after Pasolini returned to win the next GP in Holland.  By this time Herrero’s challenge had begun to wane, and it was left to the two Benelli riders to slug out the remaining rounds.  Unfortunately, Pasolini fell again in Finland putting himself out for the rest of the season.  Carruthers then became team leader, and his less powerful two-valve engine was replaced with the eight-speed four-valve unit, which he used to notch up two wins and two-second places in the remaining four rounds to take out the world title.

American made Airheart disk brakes were originally designed for go-karts.

American made Airheart disk brakes were initially designed for go-karts.

It was indeed the 250 fours swan-song, winning the championship at its last gasp.  The FIM in their wisdom had changed the rules at the end of 1969 for the 1970 season, limiting the 250 class to two cylinders and six gears, which also prevented Benelli from showing off its mind-boggling prototype 250cc V8 racer in public.

As the amiable Jon Chittleborough and I sat down in his office at the Birdwood Mill Motor Museum, it became apparent that there was quite a bit of mystery surrounding this particular Benelli.  Unfortunately, the racer was obtained when the museum was still in private hands, and there’s very little in the way of records to go by.  Jon has written to the Benelli factory in the hope of finding out a little more of the 250’s history, but regrettably Benelli English is even worse than the fabled Ducati English!

It is known, however, that the GP racer was brought into this country via Melbourne, probably by John Skepper of Zeltex Imports, who it’s thought was the importer of Benelli at that time.  The Museum acquired the Benelli as a straight swap for a 1927 DS Harley Davidson after the local agents were unable to sell it.  A previous employee of the Museum believed the Benelli was obtained from Carcycle (now Peter Stevens Motorcycles). But after checking with Mike Harris and Jim Russell (who had both been with Carcycle and its subsidiary sales team for over 20 years), this proved to be untrue, although Jim vaguely recalled seeing it for sale across the street in a shop that traded under the name of “Maintenance Services”.

Jewel-like engine is extremely compact.

The jewel-like engine is extremely compact.

Before the swap with the museum could go ahead, the importers had to get approval from the Benelli factory, which they did with the understanding that the 250 would not be raced.  This brings us to the next part of our mystery and probably the saddest part of the story.  The museums’ Benelli has had its engine entirely gutted. Whether this was done before the bike left Italy or after it arrived in Australia is not known for sure,. Although former road racer John Maher did tell the Museum he was offered a ride on the 250 GP racer by John Skepper when a Benelli 750cc six failed to show up in time for the Castrol Six-Hour production race.

It also confirms what I was told by the salesman at the motorcycle shop, who had assured me that the bike was still competitive with the production TZ Yamaha of the time.  This creates the possibility that the engine parts could still be lying around in a dusty corner of someone’s garage.

Riders cockpit.

Riders cockpit.

Perhaps the most contentious issue is whether the museums 250 was the one used to win the 1969 World Championship.  Both Jon and I agreed it was probably an earlier model, possibly 1965 as it’s fitted with the Airheart disc brakes, Lucas magneto, and “straight” megaphones of that vintage.  To add credence to this, about eleven years ago, Derek Pickard of Road and Race magazine visited the museum. He opined the view that it’s the bike that took Venturi to fourth place in 65/66 Italian Championships. Nonetheless, it’s still a very rare motorcycle. It even prompting seven times World Champion, John Surtees, to approach the museum in an attempt to acquire the 250 to add to the 500 he has on loan from the factory as there are very few “complete” 250cc fours in existence.

However, the museum would love to hear from anyone who can shed any further light on the Benelli, especially with regards to the missing engine parts as the museum would like to fully restore the 250.  The museum can be contacted by writing to The Curator, Australian National Motor Museum, Main Street, Birdwood South Australia 5234.

Words Geoff Dawes (c) 1989. Photographs Geoff Dawes (C) 1989. Published in the November 1989 issue of Bike Australia.

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The Rise Of Marc Marquez.

Two 20-year-old MotoGP winners. Marquez the youngest ever by 133 days.

The temptation to compare great Grand Prix motorcycle racers from different eras is almost impossible to resist for many MotoGP commentators.  Admittedly, it does help generate increased interest from the media, the fans, and the general public, but grabs of history both past and present that align nicely do not necessarily make for a fair comparison or do justice to those involved.

Marc Marquez has already claimed the mantle of the youngest winner of a MotoGP at age 20 by 133 days from “fast” Freddie Spencer. In 1983 Spencer went on to win his first  World Championship aged 21 years in the 500cc class (MotoGP) becoming the youngest person to win the title.  Marquez appears to be on course to wrest that achievement away from Spencer as well, currently leading the MotoGP World Championship with six rounds to go as this is written. However in 1985 at the age of 24 Spencer won both the 250cc (Moto2) and 500cc (MotoGP) World Championships, something that no other rider has done, and is a feat that is unlikely to ever be repeated. It should also be noted that Marquez started racing in the 125cc World Championship in 2008 when he was 15 and has won both the 125cc (Moto3) World Championship and the Moto2 World Championship, although he was not the youngest champion of either of those two classes.

Freddie Spencer the youngest MotoGp World Champion at 21.

Freddie Spencer the youngest MotoGP World Champion at 21.

The same commentators are also espousing that rookie Marquez may win the MotoGP title in his first year. The last person to achieve this was Kenny Roberts 35 years ago in 1978. But here there is a rather significant difference in circumstance between Roberts achievement and that of Marquez should he attain the title.

Roberts World Championship effort was backed by Yamaha America,  who only supplied his team with equipment. This consisted of three different GP racers for the three different classes Roberts was contesting. Formula 750, 500cc GP and 250cc GP – one machine for each class with no spare bikes. His crew chief was expatriate Australian, Kel Carruthers, a former 250cc World Champion and a mentor to Roberts, accompanied by mechanics Nobby Clark, Trevor Tilbury and a Yamaha technician. Roberts had helped develop Goodyear’s racing tyres in the States, and it was the American company that put up the money that was needed to go racing in Europe. Goodyear naturally supplied the tyres.

The situation was not an ideal one as Roberts explains, “When we got to our first race it became crystal clear that, for sure, I wasn’t a Yamaha factory rider. Venezuelan rider Johnny Cecotto was. It wasn’t hard to tell; all we had to do was look at his equipment and then look at ours. We did have a Yamaha engineer by the name of Mikawa, and at some races, we also had a Goodyear technician. But it was us against the factory, really.”

'78 World Champion Kenny Roberts at the '79 French G.P. at Le Mans,

’78 World Champion Kenny Roberts at the ’79 French G.P. at Le Mans,

“So ’78 was a piece of work. I was riding 250 and 500 Grand Prix and Formula 750 as well. We had just one bike per class; no backup bikes. At practically every race it was my first look at the track. Usually, all I had was 30 minutes to figure it out. And not just the track, everything–the right lines, bike setup and tire selection, if there was any. There I was, aiming to beat reigning World Champion Barry Sheene, who’d usually seen the track a dozen times before. And we were on Goodyear tires. We were on our own there, too, because nearly everyone else was on Michelins. I swear, some things never change! To say the Goodyear guys had their hands full is to understate the problems we faced. Usually, the Goodyear guys would show up at a track they’d never seen before, which meant they didn’t have the right tires. That’s a nightmare you really don’t want to deal with. But deal with it we did.”

Roberts wen ton to win a hat-trick of 500cc World Championships.

Roberts went on to win a hat-trick of 500cc World Championships.

Nonetheless, Goodyear eventually weighed in with more development tyres, and Yamaha finally supplied Roberts with a second bike for the 500cc GP class. Roberts dropped the 250cc title challenge after winning two races and at one stage leading the championship, finally finishing fourth in the standings.  Roberts continued on with the Formula 750cc World Championship finishing second in the title five points behind Johnny Cecotto. But Roberts won the 500cc GP (MotoGP) World Championship by 10 points from Barry Sheene against a flotilla of factory Suzuki’s and the works Yamaha of  Johnny Cecotto. It was an outstanding achievement.

Marc Marquez in action. A future multi MotoGp WorldChampion ?

Marc Marquez in action. A future multi MotoGP World Champion?

By comparison, Marc Marquez has raced in the world championships for five years now. In MotoGP, there is only one track that was new to him, Laguna Seca (The Circuit of the Americas was new to everyone in MotoGP this year). As a World Championship prodigy in the smaller classes, he has been groomed by both Repsol and Honda to fit seamlessly into the retired Casey Stoner’s seat at the team. With a dearth of experience from the team around him and mountain of electronic data to relate to and the use of control tyres, the only thing that can stop Marquez from claiming the title may be fate. He has proven he is fearless and usually comes out on top when pressured by his peers. Indeed if there is a similarity between Marc Marquez and Kenny Roberts championship campaign, it is the fact that they are both real racers in every sense of the word. And there is no doubt in anyone’s mind that Marquez will continue to break records.

Words Geoff Dawes (c) 2013. Images courtesy http://www.motogp.com

Read more: http://www.motorcyclistonline.com/features/122_0503_kenny_roberts/#ixzz2dn69hATZ