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- Written by Carole Nash Editor
- Created: 08 August 2008
It’s a little known fact that the humble Ducati Pantah is the granddaddy of the modern Ducati V-twin range.
This funky little 500 twin, with its belt-driven cams helped to give Ducati´s engines a new lease of life back in the 70s and can stand a bit of tuning, not to mention being bored-out to 750cc.
Chris Pearson went racing on a landmark Italian classic.
The basis for this machine is the 1978 Ducati Pantah 500SL, although this Duke has an over bored engine, at 88mm. The stroke remains original at 61.5mm giving a total capacity of 748cc.
Air cooled two valve heads are used but the tracts have been ported and flowed by Mez porting. Valves are 41.5mm inlet and 35mm exhaust, with the motor sucking through massive Dellorto 41mm carbs. The camshafts are factory spec with 350 degree duration and 147deg overlap, with 11mm lift inlet and 10mm lift exhaust.
Gearbox is the standard road bike 5 speed item, driving a 520 pitch chain. Alloy has been used where possible to bring weight down to @150kg wet. Although this Ducati has never seen a dyno, the spec of the engine suggests it produces around 83bhp, at the crank.
Wheels are 2.5 x 18 spoke front and 3.0 x 18 spoke rear with Avon AM22 race tyre on the front and a Dunlop KR144 on the rear. Right, that´s the boring technical stuff out of the way, should we go and thrash it to within an inch of its life?
WHEN THE FLAG DROPS
The ideal opportunity to test this bike presented itself courtesy of the Earlystocks club and one of their meetings at Mallory Park. Well how else do you test a race bike but get out and race it against its contemporaries! And that is just what we set out to do, with more than a little trepidation I set out onto a damp Mallory Park and wobbled around on this big thumping 748cc V twin.
The owner, in his infinite wisdom, had chosen this day to play around with a few ideas he had considered trying for some time, effectively sitting me on a bike neither he or I knew! One mod was a new twin muffler exhaust system while another featured a wider front rim and tyre.
From the outset the bike refused to go where I wanted it to and suffered huge under steer around the long, long right hander, Gerrards. The engine would not rev above 8 thou and the gear change was the wrong way round for me. I can ride either way under normal circumstances but in the heat of the battle it is nice to have everything just so.
After a steady trot round in the damp practice session we had a little time before the first race so it was decided to fit the old exhaust system to get the engine revving a bit and the original front wheel/tyre combination to get it turning a bit faster.
The seat was moved forward slightly for me short frame and the gearshift was repositioned to suit my established mental programming. The only aspect of the bike I was content with in practice was the superb Brembo brakes up front. Grabbing them with a pair of EBC pads, these were more than sufficient for the job in hand although I didn´t realise at the time that changing the front wheel would upset the braking efficiency as well.
Effectively this gave me a completely different bike on which to start the race; the handling, seating position, power delivery and gear shift would all be different this time. As the 30 strong pack hurtled into Gerrards, this would be pretty much guaranteed make life really interesting. As a bonus, I was on the front row!
Who said this was the best job in the world?
I hadn´t gained any overall impression of the bike at this time as I had been fighting it all the way around the circuit in practice. Ducati guru John Witman, of the Luton based Witty Ducati fame, had worked very hard to prep the bike and meet my requirements, so at least I was going to the startline confident of their workmanship.
John is a mine of information with these bikes, having successfully raced various types of Duke since the mid seventies. The Witty preparation is also impressive, indeed every inch of this particular Pantah has had his attention at some time or other, it looked nothing less than a full factory effort. I felt very well looked after indeed.
On the bike ready for the first race and it immediately felt different. A quick blip of the throttle showed the engine to have more life as it spun up just that little bit quicker. In the warm-up area for the first time with the rest of the grid I was put at ease by riders´ smiles and head nodding (the only way racers can communicate when dressed for battle) and after a few minutes waiting, we were allowed out on to the circuit.
I took my place on the front row and tried to assess who was going to be fast and make the break. There were a couple of trick looking GS1000 Suzuki’s and several menacingly prepared XJ550 Yamahas as well as loads of RD400s RD250s etc.
The flag dropped and I dumped the clutch, launching into the unknown, aboard my pulsating Latin mount.
A bit of quick reprogramming to get the gear shift pattern installed in my early morning (read hung over) brain and off we sped to the awe inspiring Gerrards. When the dust settled I found myself around about fourth place. Now bear in mind the last time I rode this bike it was under-steering so badly that any kind of excessive manoeuvre was not really possible.
I leaned a little further, just gassed it around the outside of the pack. The Duke was steering so much better now with the thinner front tyre and I found myself gaining on the leading bunch through that first corner.
STOP ME AND TRY ONE
Through the Esses uneventfully and up into the hairpin for a mad do or die braking move to take the lead. You´ve guessed it, no brakes!
Thank god for Desmodromics, as any other type of engine would have plaited its valves after what I had to do to haul the Duke up - I had visions of landing in Hinckley town square.
The replacement of the tyre meant using a different wheel and discs, one of which was warped, pushing the pad back every time I wanted it on the disc to slow me down. I wasn´t going to give up at this stage however, so it was steady through the bus stop and as we passed the start and finish straight I wound out the span adjuster on the front brake lever to the max, enabling me to carry on.
I had lost more than a little time with this problem and was lying in fifth position a few yards behind a very quick XJ550 Yam (I don´t remember the 550 being a particularly fast bike when new, but this one, along with a couple of others, certainly are now). The lever idea worked to a certain extent as it gave me more travel to push the pad onto the surface of the disc although the juddering under braking caused by the deformation was a little disconcerting.
As the six lap race wore on I became more settled on the V twin lapping consistently faster with each circuit and I started to appreciate the power delivery of the 90deg engine. Vibration at certain revs was quite excessive but not too uncomfortable.
The machine sadly lacked a close ratio gearbox and this was a bit of a problem at the hairpin. Using the normal tight line in first gear meant the engine was at max revs mid corner with very little power, however if the corner was taken a little faster in second with the revs somewhere around max torque, we were left with somewhere to accelerate into. So that was the technique, throw it in on a wide line using second gear, everything on the deck, and ride the considerable camber, accelerating all the while up to the Bus Stop chicane. It certainly worked for the lumbering twin, with the added advantage of saving two gear changes per lap in the process.
The engine was now breathing properly with its old exhaust system back in place and topped out at 9500 revs along the back straight. However this was only possible if I got completely behind the screen. If I sat slightly up and out into the airflow, so I could see, then the engine lost at least 250 revs.
We crossed the finish line still in fifth having lapped faster than the owner of the Duke ever has, winning the 750cc class to boot. The outright winner, on his GS1000 Suzuki, lapped less than half a second quicker than the old Duke - so we were definitely on the right track.
Were it not for the problems with the shuddering brakes, then I think we would have been in with a shout at the top spot. These Earlystock boys and girls are certainly quick and the pace up front wouldn´t disgrace a field of modern bikes.
Perhaps Mallory, being very fast with a high average speed, was not the best track for such a bike but get it on the Cadwell full circuit and it would be a very different story.
The engine is powerful, torquey and bullet proof, well capable of standing my ham fisted abuse all race long. I just rode it like a grunty two stroke, confident that the desmo bits would prevent any unnecessary heartache, although those little rubber belts whizzing about just to the side of my right knee took a little getting used to.
It all went to prove one thing; you can have just as much fun racing a fettled classic motorbike, as you can aboard the latest hot-shot, four cylinder 180mph plastic rocket. The old `uns tend to sound better too.
Get Ducati motorcycle insurance for the ducati pantah 750.
|Engine||Air cooled, four stroke, V-Twin|
|Claimed power (bhp)||83bhp|
|Bore and stroke||88mm X 61.5mm|
|Carbs||Twin Dell´Orto 41mm|
|Frame||Steel tubular trellis type|
|Front suspension||telescopic forks|
|Rear Suspension||Twin shocks|
|Brakes||Brembo twin front discs, single rear disc, EBC brake pads|