[technicalities]

[TECHNICALITIES]

GORDON H. JENNINGS

TOURIST TROPHY practice here on the Isle of Man is, in many ways, more interesting than the race itself, for it is during practice that one sees mistakes being made and sometimes even corrected, and it is during practice that some machines are wheeled back to the garages, never to be seen again. Also, by going around to the various teams' garages, one may see (just before the doors slam shut) all manner of interesting things.

Interest this year is centered largely on the 3-cylinder MV and Yamaha's new 125 twin. Suzuki and Honda have some fascinating equipment, of course, but it is not quite so new and mysterious. Actually, it would appear that the Hondas will always be something of a mystery, for they are kept under wraps and anyone standing about with a camera is likely to be charged upon by an overall-clad samurai if he gets too close. And, in fact, one British journalist has been declared persona non grata around the Honda camp for having sneaked a picture of the new six-cylinder 250 with the fairing removed. What secrets they expect would be given away by a photo of the engine's exterior is anyone's guess, but they are very touchy about it in any case.

However secretive the inscrutable Honda team may be, they are absolute marvels of friendly and open behavior compared to MV. Get anywhere near MV's new 3-cylinder 350 and the garage doors come down like the headman's axe, and woe unto anyone who happens to have his head in the way. Despite this sort of goings-on, one can gather a general impression of what it is all about. The three is, to such extent as we were able to see, a very straightforward in-line engine, with the camshaft drive going up one end, through gears, and another geardrive at the other end of the crank to pass the power along to the clutch. The cylinder head is cast in one piece, but the cylinders themselves are all separate. I would judge, from the shape of the head and positioning of the spark plugs, that this is a big-bore, short-stroke engine, with a comparatively shallow valve angle, having concentric-coil valve springs and inverted-bucket tappets. It almost surely has two valves per cylinder, but turns up a lot of revs. There is a clue to the high engine speed in the short intake length. The three Dellorto carburetors are tucked right up against the head, and are fitted with very short funnels.

(Continued on page 12)

The MV engine's crankcase extends back to include the transmission, and the entire package is quite compact. It is fitted into a conventional double-cradle frame, and in all, follows previous MV practice quite closely. The handling is obviously good, but it is significant that there are alternate mountings at the back of the swing arm for both axle and suspension units so that the wheelbase can be changed over an approximate 3-inch spread on very short notice. Chain-tension adjustment is done by means of eccentrics at the swing arm pivot.

While the MVs are all equipped with drum-type brakes, of the 4-shoe, doubledrum pattern up front, there was a front wheel and forks, and a rear wheel, outfitted with disc brakes. Twin discs at the front, and a single disc for the rear wheel, with scissors-type, mechanically operated calipers all around. At this writing the disc brake setup has not been tried here at the island, and indeed the hardware has disappeared from sight. When asked if the discs will be tried, the MV mechanics shrug, look off into space, and suddenly do not speak English and only a very little Italian.

If the reader will permit a guess, the guess would be that MV is coming back into racing in a big way and that the 3-cylinder is primarily a test-bed for a 4-cylinder to follow. The "four" now in use is getting very long in the tooth, and while MV have no opposition now, Gilera is supposed to make a comeback and it is known that Honda will compete in all classes in which they have road machines and that now means a 500. Also, we should not overlook the fact that in newboy Agostini the Italians have a potential world champion for the first time in vears. The Italians, being what they are, have never been too enthusiastic about producing bikes for foreign riders anyway, and now that MV has a local lad who can make good they will surely go at it more seriously than in the recent past.

(Continued on page 14)

Certainly, they are most serious about racing here at the TT. Thev have brought along enough machines to have a race all their own, and a brigade of mechanics and technicians. All pretense of being "privat" entries has, of course, been dropped. MV is here in force, and they would like for Agostini to win. So would he, for all that, and he has been practicing for weeks, going around and around this 373/4-mile course to get things fixed in his mind. Unfortunately, at racing speeds in official practice he has to learn a lot more, and most observers agree that his initial racing laps have been more than a trifle ragged. He is fast, and quite obviously has enormous talent, but is as yet no match for Hailwood. Hailwood is, by the way, the only man at the island who can (by expert account) "scratch" all the way around, just as if the island's mountain circuit was Brands Hatch. Mike the Bike will take some beating. It is generally thought here that MV likes to think of Agostini as Hailwood's replacement. If that is true, Agostini will either develop into a scratcher to end all, or be sent back to Italy in a box from trying too hard.

Next to Hailwood, and probably on par with him, is Phil Read, who Geoff Duke says is so good that people don't think of him as being nearly as good as he is. Read rides for Yamaha, of course, and this is a partnership that will be hard to beat. At this time, Read has already done a lap at fractions under 100 mph, and there is every reason to expect that he will top 100 in the race. He will ride the well-proven and now quite reliable 250 twin, and the new 125.

Both air and water-cooled versions of this 125 twin are being tested in practice, and emphasis appears to be on the water-cooled version — which, as everyone knows, will form the groundwork for the 4-cylinder 250 that Yamaha has lurking in the background. The 125 twin is, as one might expect, very much like the 250 twin, but has its crankcase split horizontally instead of vertically between the cylinders. Frame and suspension follow the pattern set by the Yamaha 250, but where Girling rear suspension units have been used exclusively on the 250, the 125 is outfitted with Yamaha's own dampers. Why? It is a matter for conjecture, but Read has said that the 250 is a bit wiggly under full throttle (which is the normal condition with him aboard) and Yamaha may be resorting to custom-made and rather special dampers in an effort to sort things out. Actually, things cannot be too bad, because Read, Duff and Yamaha Team newcomer Bill Ivy are all going well. Taking everything into account, Yamaha appears to be one of the strongest teams here, with a depth in rider talent, and perhaps the bestlooking machines on the island. They don't appear much ruffled by anything, and I was so taken by the Yamaha motorcycles that I didn't even mind much when their garage doors were nearly closed on my nose as I peered in at a partially disassembled engine.

Despite the Yamaha air of quiet confidence, it will almost surely be Suzuki in the 125 class. They have nothing new, but the motorcycles they have been using (water-cöoled 125 twins) seem to be fast enough to do the job. Ernst Degner, Hugh Anderson and Frank Perris have been taking turns hammering everyone else under in practice, and it would not be too surprising if this trio sailed home 1-2-3 in the race. The Honda and Yamaha 125s are not far behind, and could find the speed to upset this prediction, but at the moment it is Suzuki.

Suzuki's 50s and 250s on the other hand are running a bit off the pace. Honda 50s in the hands of Bryans and Taveri have been whacking around at over 80 mph, average, and do not seem strained at all. The Honda 50 is an 8-valve twin, with who knows how many speeds in the box, and it makes more noise than a Norton 500. I watched Bryans, on a Honda 50, tuck in behind some unfortunate on a 250 production-racer and accelerate with him all the way from Quarter Bridge to Bradden, where he nipped by when the unfortunate sat up and braked for the turn. When the factory 50s will do-in privately entered 250s, you know what sort of chance the privateer has here at the TT.

(Continued on page 16)

After much trouble, the Suzuki 250 is beginning to do rather well. Giant-Jack Ahearn, whom Degner says is the only man around strong enough to give the rather heavy water-cooled "four" a semblance of agility, has gone around in reasonable time, and so Suzuki may figure in the 250 race after all. Potentially, the Suzuki 4-cylinder is the fastest of all the 250s; and if thev can get it perking properly, Ahearn will have it up among the leaders as he seems well suited to the brute.

For the first time in a long time, Honda appears to be in trouble. The 250 6cylinder has a record of collapses unblemished by a single spot of reliability, and in this, the most taxing of all races, it will very likely pack it in again. Also, Jim Redman does not appear to be entirely on form — trying far harder and accomplishing much less than is his habit. Of course, the Honda 6 has demonstrated that while it lasts and is running on all 6 cylinders, nothing will touch it for sheer speed. For that reason, it would be foolish to entirely discount the possibility of a Honda 250 win. ( Very foolish; it won — Ed.)

For some reason, the Honda 125s that did such astonishing things to the opposition here last year have not been as fast or reliable in subsequent races. These are 16-valve fours, and should (on paper at least) run away with the 125 race — especially since Honda has Taveri to do the honors, and Luigi is just about as good as there is, mate.

A dark-horse in the 250 race will be Provini on the Benelli four, which is a straightforward little machine that has about as much speed as anything in the class while it lasts — and it has been getting more reliable right along. The main trouble with the Benelli would seem to be a lack of money, for of all the factories present, the Benelli operation is the most modest.

One new development on the Benelli is the dual-disc front brake, which uses American Airheart hydraulic calipers. Initially, these single-piston calipers were used in conjunction with floating discs, but Provini said that with that arrangement the discs clattered about too much and set up a shuddering under braking. So, now they have fixed discs and the calipers have floating mounts. With the present setup, Provini thinks the discs are clearly superior to the drum brakes used until late last season.

The Jawa/CZ combine have brought along a pot pourri of 125, 250 and 350 motorcycles, with a very nice little 125 twin, 250 twins and singles, and 350 twins and singles. Unfortunately, none are fast enough to pose much of a threat except to the privateers. Then too, of their riders, only Stastny has much experience, and much of his recent experience has consisted of landing on his head at various and sundry race meetings. He is one of the most likeable and popular riders about, and an altogether worthwhile human being. Unfortunately, he must contest these races with men who are perhaps not so likeable and worthwhile, but are younger and in peak form. It is all an unpleasant fact of life that I will leave the reader to ponder on.

The very nice little CZ 125 twin will be out again this year, but carrying a Jawa name-plate, in the hands of Havel and Bocek (from Czechoslovakia). They are listed as private entries but are in fact works-supported. While the bikes have new frames, they are much the same as the CZ 125 seen here last year — which was quite fast now that I think about it. No match for the big-name entries probably, but very competent little machines for all that.

Essentially the same sort of design features, with a shaft drive up to the exhaust cam and another shaft reaching back to the intake camshaft, is seen in the Jawa 250. It too, strikes me as being a very nice bit of machinery, but is also up against it when one considers the opposition. Many people have voiced the opinion that what Jawa should do is to produce these machines in limited quantity for those who are racing in noninternational events. The Jawa road racers are far superior to anything now available to the privateer, and if Jawa made them available, they would surely rack up a lot of wins in national-level races, which appears to me at least to be better than always running just behind the big, wellfinanced teams from Japan. After all, the Jawas are very good. But they are fighting virtually overwhelming odds and while they show remarkable speed for being as straightforward as they are, they have no real hope of winning except by default. At best, they will spend the race keeping near the leaders and hoping that their basic reliability will see them through.

And then there is the other "Iron Curtain" entry, the MZ. These East German bikes will be contesting the 125 race with a single, and the 250 with a twin. In most particulars they are the same machines as were used last year, water cooled and with rotary valves (MZ racing chief Walter Kaaden, can virtually lay claim to having created the modern racing two-stroke). The only real departure from last year is in having bigger brakes, and (on some machines) a Lucas "transistorized" ignition system. In this connection, I might mention that there is a privately entered water-cooled Bultaco 125 that has the same sort of ignition; only Bultaco seems to have done the job without all of the batteries, bits and ends featured in the Lucas system. In fact, all current for operating the Bultaco's system is generated by the flywheel magneto. The Lucas system is a modified version of the magnetic-trigger unit they had developed for racing cars.

(Continued on page 18)

With Walter Kaaden directing things, there is always a chance for the MZs, but this year they are handicapped by having only one really experienced rider, Derek Woodman Woodman has gotten around on his 125 and 250 MZs quickly enough to place him on the leader-board, if not in the lead, but it will be a long race and attrition among others (namely Redman and Read) could bring MZ right to the front. Certainly, they are making an all-out effort this year, with flocks of machines and mechanics.

The trade representatives here are buzzing around, passing out goodies to the deserving. Shell Oil Company is very much in evidence, and looks to be making inroads on what was once virtually a Castrol preserve. Dunlop has sprung a new tire, this time a triangular-section front tire to match the rear tire brought out last year. They are in short supply, and are going mostly to the big teams, with a very few for favored non-works entries. Reportedly, the new tire is quite good. Lucas reps are, as one might expect, hovering over the MZs, installing and caring for the transistor equipment.

There are a couple of very small teams here from England: Cotton and Enfield, with 250cc, single cylinder production racers. The Cottons are getting around rather quickly, though not anything near fast enough to win, but even so will likely be the fastest production racers in attendance — excepting possibly a group of Aermacchis that flit along like no pushrod single ever should. You lads at home who are running Harley-Davidson Sprints might like to know that these bikes are fitted with very long, slow-taper megaphones, quite unlike those seen before.

At this time, with practice nearly over, the Enfields are said to be in trouble. They still do not handle quite as they should (last year one of them suddenly broke into a gallop and pitched Griff Jenkins off on his head without so much as a warning quiver) and team boffin Meier is trying, unsuccessfully, to cope with a tendency toward plug oiling. Add to that a problem with the clutch and you have a dismal prospect for a more than 200-mile race over a circuit that demands exquisite handling and vast amounts of clutch brutalizing. The extent of the difficulty may be judged by the fact that one of the Enfield's runners, Rex Butcher, has quit in the middle of practice and gone looking for a ride.

And, speaking of clutches, John Cooper liad (note that past-tense) a new type clutch in his Greeves, but it sheared away where it was welded at the hub and he was treated to the rare privilege of seeing the thing pass him going right on up the road. Whatever frailties a bike may have, they will come to light here at the Isle of Man, for it is easily the most difficult and destructive race on the international calendar. A road race to top all road races — which is, I suppose, precisely what makes it so popular. •