Cycle News - Archive Issues - 1980's

(Clockwis. from top left) Connecting rod. ara joined to a pr...·fit crank that run. on four roUer bearing•. Bora fe.ture••Ix tran.fer .nd one exhaust port. A prancing horse Is the team'••ymbol; "Ad Malora" i. Latin for "On to greater thing.... Right .lde of .nglne .hows rotary valve. all it takes to buIld it is money' It'll be expensive because completely new cast· ings are needed, but maybe Melandri can do it in '82. We'll see," he says. So for the time being the team will be using the present design, basically unchanged from the original Mor· bidelli of 1976, but with many modi· fications. The water·cooled motor measures 55 x 52mm - unusual when al} other 250s are 54mm square with the cylinders inclined forward at 45°, running a 13: 1 compression ratio and producing a claimed 67 bhp @ 12,000 rpm; power in produced from as low down as 7,500 rpm, giving the riders one of the widest powerbands in the two·stroke business to play with. Freymond confirms it: "The bike's much easier to ride than the Yamaha I used to race, even though it's a disc· valve design; the only problem with the engine at present is a high-speed vibration between 10-12,000 rpm, but we hope to have solved this now. I'd have been second in Argentina if the vibration hadn't cracked the fuel tank." Moller takes responsibility for the design faults, as well as the successes. "The crank vibrates at high speed because I made a couple of mistakes when I designed it. Fortunately, a couple of the others copied the design, so they're now experiencing the same problems that we have almost solved." Who are they? "Well, just look at the Pernod, or an MBA ... '" Battery-powered Krober ignition and 34mm Mikunis power the Ad Maiora; the disc valves are in ste I land th .. .. 01144 JI " single-ring piston made by Mahle in Germany: "I go to the best available supplier for all material," says Moller. One of his first acts on rejoining the team was to fit new barrels, designed and made in the space of just two months using a computer, The result? A pair of Nikasil bores with six transfer and one exhaust port, but still with forward facing exhausts. The team tried reversed cylinders last year before Moller's return, but they weren't a success. "Basically we need very long exhausts with this engine to produce the power curve we want," explained Jorg, "and there· just isn't room to squeeze them in and still have them ending inside the rear wheel with the reversed cylinders. I use a computer for all my design calculations now, and with the new cylinders the valve is shown to full advantage - they were right the first time, as the result in Argentina proved." The pressed-up crank runs on four ball bearings, with needle roller small ends and roller big ends. Primary drive is by 3: I reduction gear off the right side of the crank, feeding a six-speed gearbox made by the CIM company in nearby Bologna. An II plate clutch (six friction/five steel) runs dry, and has given constant problems this season which the team have tried unsuccessfully so far to cure. It's not possible to change the internal gear ratios. The complete engine uJlit weights 72 lbs., and is carried in a Niko Bakker-made double cradle chromoly frame that on its own weighs only 28.~ • ..~M"" ) lbs. including the rear suspension arm. Over the winter this was modified' from the cantilever system used last season to a rocker-arm layout. Moller says, "The cantilever is finished; the rocker arm design is the way of the future." In spite of his confidence though, the team has had considerable trouble this season with the rear suspension unit. Originally a Bitubo, this was being replaced by a new Marzocchi design when I was there - apparently the handling suffers when the rear unit goes away after only three-four laps. Adjustable Marzocchi front forks are fitted, with Grimeca brakes operating on beautifully made, plasma-sprayed alloy Zanzani discs, 260mm in diameter and fully-floating; a single 230mm drilled cast iron unit is fitted at the rear. The team now use Dunlops exclusively - "much better than Michelins at present," says Jorg. All-up weight is around 225 lbs. dry, and the riders report good handling apart from the rear unit problem: "When I first built the bike I had to use a Bimota frame," says Moller, "but it handled very badly and was too complicated to sort out easily. So I got Bakker to build me a much simpler design, and a apart from sheer metal fatigue on one frame, we've had no trouble since. At one stage Morbidelli was thinking of putting the bike into series production alongside the 125cc, but he decided there was too much competition so forgot about it. I think that was a pity, same as we have the one and only 350cc engine I built in 197f? sitting over there on the shelf it's hardly ever been used, apart from a few outings with Pileri and Lega, but it could beat any of the Japanese bikes in the 350cc class with a bit of money spent on development. That's the trouble here - it's only a small team, and we've done very well considering how long it inevitably takes to make any improvements or get new parts made. I'll stay here till the end of the year, but I definitely want to build a 500cc bike - I have the design roughed out alrady - and I'm close to signing a contract to do so with a major manufacturer (strongly rumored to be Gilera) which will give me the budget I need to beat the Japanese. Mter all, I proved I could do it in the 125 and 250cc classes, so why not in the 500cc?" Jorg Moller may not be everybody's cup of tea, but he certainly has earned his other, more respectful, name of the "Wizard of the two-stroke." Who's to say he can't make it a hat-trick of World Championship class successes if the Gilera deal comes off? Suzuki and Yamaha - look to your laurelsl Meanwhile, the Ad Maiora team looks forward to 1982, with Moller's bequest of a new design on the horizon. • Editor's note: Roland Freymond took the Ad Maiora to a second-place finish behind defending 2,Occ World Road Race Champion Anton Mang in the second to last round at Anderstorp, Sweden on Aug. 16. 25

• Cover