Ducati Pantah Race Bike

Ducati Pantah Race Bike

Ducati Pantah Race BikeAllan McKee is a regular in UK magazines having featured along with his 1100 Katana as well as a regular competitor with the FRC and the Earlystocks club. He contacted the me some time ago about his pretty trick pair of Duke’s but various things (snow and ice etc) conspired to prevent a test ride until fairly recently. Based on a 1978 Ducati Pantah 500SL, Allan has bored and stroked engine to 88 x 61.5mm giving 748cc. Air cooled two valve heads are used ported and flowed by Mez Porting. Valves are 41.5mm inlet and 35mm Exhaust sucking through massive Dellorto 41mm carbs . Cams are factory spec with 350deg duration and 147deg o/lap with 11mm lift inlet and10mm lift exhaust. Gearbox is the standard road bike 5speed item driving a 520 pitch chain. Alloy has been used where possible to bring weight down to @150kg wet. Although Allan has never had the Ducati on a Dyno the spec of the engine suggests it produces about 83 BHP 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 stuff out of the way lets go and thrash it to within an inch of its life!

The ideal opportunity 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 contemporary’s, 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.

Ducati PantahAllan in his infinite wisdom had chosen the 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 commanded and suffered huge under steer around the long, long right hander, Gerrards, the engine would not rev above 8 thou ( Allan told me before that first practise session that it revved to 9k at least) 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. Also, due to an old racing injury sustained by Allan many years ago, the left footrest was some five inches further forward than the right (he will have it that it is because he is hung like a donkey and dresses to the right but don’t believe him!).

I knew nothing of the Earlystocks club before this meeting and unfortunately didn’t come across any of their bikes in practise so I could not judge whether or not the Duke was going to be competitive amongst the pack until the race actually began. In the paddock the Earlystocks boys certainly came across as a jovial and friendly bunch and they made me feel welcome throughout my day with them, but would they be so kind on the track?

After a steady trot round in the damp practice 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 tyre to get it turning a bit faster. After careful examination it was decided we could also move the left footrest rearward to a reasonable position for me. The only aspect of the bike I was content with in practise was the superb Brembo brakes up front, grabbing a pair of EBC discs these were more than sufficient for the job in hand although it wasn’t realised 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 as the 30 strong pack hurtled into Gerrards, and just to make it really interesting I was on the front row! Who said this was the best job in the world?

Ducati Pantah Race ShotI had not gained any overall impression of the bike at this time as I had been fighting it all the way around the circuit in practise and in reality was not looking forward to the race based on those initial damp, slippery laps. To be fair Allan and his Ducati guru John Witman, of the Luton based Witty Ducati fame, had worked very hard to prep the bike and meet my requirements so I at least was going to the line 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 on factory effort. I felt very well looked after indeed.

The tannoy system blurted out the call for our first race and I dutifully got togged up trying my best to look like a professional as Allan bumped the big Duke into life. As he handed the bike to me it immediately felt different and a 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) after a few minutes we were allowed out on to the circuit and make our way to the grid. I took my place on the front row and tried to assess who was going to be fast and make the break, there was a couple of trick looking GS1000 Suzuki’s and several menacingly prepared XJ550 Yamaha’s as well as loads of RD400’s 250’s etc. Such is the variety of the Earlystock grid there was even a crazy guy on a Husqvarna 510 motocross bike kitted out with race tyres but precious little else that endeared it to road racing.

Ducati Pantah at GerrardsThe flag dropped and I dumped the clutch, launching into the unknown aboard my pulsating Latin machine amongst a field of Jap rice burners plus the Husqvarna which defies any kind of endearment. 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 behind Geoff Smale, on of all things an immaculate and very standard looking CBX1000. My first thought was that the pillion seat on the CBX, which was well within my reach, looked very tempting and a better bet for a safe return to the paddock than my current mount! The sight of all six pipes pumping out their gases right at me caused me to attempt a pass around the outside and get out of the way of this monster. Now bear in mind the last time I rode this bike it was under steering so badly that this kind of manoeuvre was not really possible but what the hell this is a race after all. I leant a little further, just gassed it and around the Honda six she went, the Duke was steering so much better now with the thinner front tyre and I found myself gaining on the front bunch through that first corner.

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 was not going to give up at this stage however so as we passed the start and finish straight I wound out the span adjuster on the front brake lever to max and carried on. I had lost 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 good/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 90-deg engine. Vibration at certain revs was quite excessive but thankfully Allan has seen fit to rubber mount the seat assembly otherwise I would have ended up with a butt like a Flanders poppy (bright red and shot to pieces!).

Ducati Pantah at HairpinThe technique I developed for getting the Duke around the famous hairpin at Mallory I must admit I stole off John Cooper. He once told me that he used to ride it like the wall of death, so I tried the same technique. 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 the maximum torque, which I felt to be something like 50ftlbs at the 7 thou mark, we were left with somewhere to accelerate into. So that was the technique, throw it in using second gear, everything on the deck and ride the considerable camber accelerating all the while up to the Bus Stop, 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 it’s 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 but as you can see the screen fitted to the bike is absolutely black, so it meant riding blind. 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 Allan ever has on this bike and won the 750cc class to boot, the outright winner on his GS1000 lapped less than half a second quicker than the old Duke by the end of the proceedings so we were definitely on the right track. Were it not for the problems on the first lap then I think we would have been in with a shout at the top spot. These Earlystocker’s are certainly quick and the pace up front wouldn’t disgrace a field of modern bikes.

I felt the shuddering brakes were costing me at least half a second a lap so that area definitely needed attention. Nothing could be done at the meeting however as the discs on the spare wheel were a different fit, perhaps another day?

Before the next race I felt that the steering could be even quicker if we dropped the forks through the yolks by half an inch, John Witman agreed and the mod was carried out. Again the Duke and me took our place on the grid I was feeling at home on her now and understood the engine/ chassis configuration fully. Ok it is a million miles away from the usual Jap stuff I have ridden for most of my working life but it gets results and that is what matters. This engine really is the basis for the current 916/996 generation of Superbike as indeed is the steel tube frame, the blood line is traceable right back to the first Pantah from 1978. This is the engine that forced Honda to change tack last season and produce, in its likeness, the SP1. The designer of the Pantah must be feeling pretty smug, imitation is, after all, the sincerest form of flattery.

The flag dropped and once again the Duke thundered into Gerrards in the first five, things were looking good and I felt very relaxed and confident. That beautiful CBX was there again so this time I rode around the beast without any hesitation. Talking to Geoff Smales in the paddock afterwards he told me that the CBX is an excellent sprint bike hence the great starts and first lap, first corner position.
Halfway around the long right hand bend the engine stuttered and faltered, the engine braking on these things is immense so when it dropped onto one pot whilst at full lean I must admit I fully autographed my underpants (They will never be white again and I would certainly be the victor in the Daz door step challenge).

The very first bike I ever rode on a race circuit was a Ducati single back in 1977 and the last bike I ever rode was also, very nearly, a Ducati single. Allan, in the confusion of turning up and not actually riding, had neglected to turn on the petrol for the rear cylinder leaving me mid pack mid corner with very little power. I struggled onto the back straight and blindly fumbled around with the tap eventually electing to turn the lever a full 180 degrees out of sheer desperation. All of this time I was still hard on the gas with the only respite for the fuel system coming at the Hairpin and even then, due to the “Mooneyes” hairpin style, the throttle wasn’t closed for long. Due to the nature of the circuit it took nearly a full lap to fire on two properly, the 41mm Dellorto carbs were sucking the juice almost as fast as the tap could supply it, and a misfire then continued for another lap.
This is a common problem that is often over looked with converted road machines as tuned engines running flat out on the race track require big bore fuel taps to supply the required amount to the carbs. In the confusion I lost touch with the leading bunch but once the two Italian tenors below me began to sing the same tune we managed to maintain the same distance from them until the end.

The front end was getting better all the time with the forks dropped down and the whole lot turned in and out of corners very well, particularly noticeable at the dreaded Bus Stop. I think the forks could stand another half an inch and still be stable in a straight line. All in all I was impressed with the Ducati and would love to have had more time on the day to fully develop such a bike to my personal liking as I feel the design has a lot to offer over the Jap multi’s. Once these things are something like sorted they will go around corners as if they are on rails, that has been a Ducati trade mark from the outset.

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.

Allan, along with John, is currently developing engines at 851cc and 878cc, it is hoped these can be installed in to the chassis during May / June, it is fully expected that the output from these big bore motors should be in excess of 90bhp with a corresponding rise in torque. The whole project is a testimony to the Ducati marque, Allan’s faith and John’s technical know how. This is really only the start of the development and Allan has much more planned for the old Pantah. Like I have said earlier the 916 originally started off on a Pantah bottom end so that is the kind of power it can withstand.