(technicalities)
(TECHNICALITIES)
GORDON H. JENNINGS
No ONE is SAYING MUCH about it these days, but if all goes according to plan the AMA's change to a 45 cubic-inch displacement limit for overhead-valve engines will come into effect for the 1967 racing season. All of the indications are that the new rule, voted into being 23 to 3 at the 1964 AMA Competition Committee meeting, will become the law of the land right on schedule. This, despite the fact that most of the people directly involved in racing are not at all enthusiastic, and the fact that many of the riders are frankly worried at the prospect. At least one topranking rider has threatened to retire should the AMA proceed with the rule change. Whether he will, or not, remains a question. Probably, even though there will be a lot of bickering and threats, the riders and everyone concerned will in the end simply make the best of the situation.
Actually, while the people in racing are not overly enthusiastic about running 45 cubic-inch, ohv equipment, there is a reason for the change in rules. Virtually all of the bigger-displacement motorcycles being sold in America today are 40, 45 or 55 cubic-inchers, with 30.5 cubic-inch motorcycles supplied in fairly limited quantities for racing only. Indeed, the companies supporting racing programs are all, in effect, importing or producing special models for competition use. Now then, it being one of the basic tenets of the AMA faith that the racing bikes shall be a direct counterpart of the motorcycles sold to the public for ordinary touring, this situation is awkward. And besides, under the existing rules, importers of motorcycles must bear the burden of low-volume sales of 500cc models, and stock parts for them. The single big manufacturer here in America is in an even worse position, being obliged to produce a special motorcycle solely for racing without even a semblance of sales outside the competition field. Eliminating the special models will make life much easier for the various sales and service departments.
But what of the racing riders? Has any thought been given their welfare? Not on your sweet life! No matter what the more starry-eyed spectator might think, the riders are not supermen; neither are they entirely fearless. All make mistakes, and the kind of horsepower that is inevitable with 45 cubic-inch ohv engines will give those mistakes definitely lethal overtones.
Circumstances have brought us a sort of preview into the kind of racing we will have once the new rule has gone into effect. Some weeks ago my good friend Jerry Branch showed me a very special Harley-Davidson Sportster that has been left in his keeping. When I first saw it, it was all set up for TT racing, which is really not too unusual. What made this motorcycle different was its engine, an item recently emerged from Harley-Davidson's racing department. This brute produces something in excess of 80 bhp, and Jerry said that while it was shockingly fast in a straight line, it simply had too much power for its intended purpose. Some very good TT riders had tried it, and all said it was absolutely unmanageable.
At that point I ventured the opinion that it might make an interesting engine for a road racing motorcycle. Branch apparently shared this opinion, for he promptly offered to install it in one of Harley-Davidson's KR road racing chassis. The object of this little exercise was for me to run the bike in one of the local road races, where there is an "unlimited" classification that covers such creations. In fear and trembling, but overcome with curiosity, I agreed.
At this writing, the bike has been completed and we have had one test session, during which some problems of a minor nature were uncovered. However, not many laps were required to tell me a lot about this particular motorcycle, and about the forthcoming 45-inch displacement rule. Even though this machine had 10 extra cubic inches over the 1967 maximum, it is unlikely that Harley-Davidson's racing engines for the new formula, when they appear, will have less power. The new engines will be de-stroked Sportsters, and the shortened stroke will allow enough of a bóóst in crank speed to compensate for the drop in displacement. So, this experimental "one-off" can rightly be regarded as what we can expect of machines built to the 45-inch rule.
(Continued on page 14)
As might be expected, the Super-Sportster is a fearsome thing to ride. It has slathers of power, and the thought is always present that a trifle too much throttle when pounding out of a turn would drop the machine in a flash. Of course, in test riding there is no particular problem in maintaining control. The power is delivered fairly smoothly, once the revs are up, and with a little practice the bike becomes an enormously enjoyable thing to ride. Nothing else in the world will give you that mighty surge down the straights. Unfortunately, test riding and racing are not quite the same. In the heat of competition a rider will never show the same coolness of head that he displays while testing. With the tires near the limit of adhesion from cornering loads it is always easy to hook too much throttle. Given a total of 80 bhp, no more than a nudge would be needed to push things completely out of control.
In all probability, the old campaigners in racing would adjust to the added power without too much difficulty, and on a lot of courses the higher incident of slides and ensuing falls would not produce serious injury. Unfortunately, not all the men in racing are seasoned veterans, and not all of the tracks are particularly forgiving of mistakes. In fact, under the existing system of rider advancement and race scheduling, we bring together the worst possible combination of track and riders. At Daytona, the first road race on the calendar, you will have the first-year Amateur-class riders, who have just moved up from riding 250cc-displacement motorcycles. Under the present rules, this makes things a trifle sticky, but not unreasonably so. Development of the small-displacement bikes has been so accelerated in recent years that they are very little slower than the big machines — and in some instances they are faster. Anyone who has been riding a TD-1B Yamaha, with a top speed of 130 mph, is not likely to be overwhelmed by the additional 5 or 8 mph of a 500cc ohv or 750cc side valve engined motorcycle.
All this will change with the 45 cubicinch overheads. Harley-Davidson has already run a Sportster-engined KR at Daytona, while making tire tests with Goodyear, and although this particular machine had only (only?) 70 or so horsepower, it was running down the back straight at slightly more than 170 mph. With 80 bhp we can expect everyone to be thumping along at about 175 mph on Daytona's long straight, and making it through the steeply-banked turns at probably 150 mph. As those who have ridden there may have noted, there is a very solid concrete wall on the outside, and anyone who drops it at the speeds we have been discussing will very likely be sent home in a box. To send out a bunch of first-year Amateurs, fresh from the 250s, to do battle in their first race on super-fast motorcycles and in the first and premiere event on the AMA's road racing calendar, is to invite disaster.
Continued on Page 16
Even among the more experienced experts there is sure to be trouble. Some one of their number will always exceed the limit when the going is hot and furious; the penalty they pay for their excesses will gain in severity with the gain in horsepower. This will, I am sure, be all too true in road racing, and T am equally sure that it will be true on the one-mile ovals.
Perhaps I am simply being too pessimistic about this whole matter, and that all and sundry will be able to manage 80 bhp racing motorcycles without any more difficulty than is now experienced with 50 bhp. But, if the assumptions set forth here are correct, a lot of riders are going to get hurt. Blame for this, if blame there be, will have to go to the AMA's "BeltDrive Bunch," who do not appear to appreciate that motorcycles have become much faster than in "their day," even without the impetus of all that displacement. Times change, gentlemen. Today's 250s are as fast, or faster, than the 500s of twenty years ago, and the current crop of big bikes are even faster than that. Bigger engines and more speed will do little to help popularize racing. Especially road racing, a sport in which the AMA is obviously most interested and is gaining
knowledge; but equally obviously knows relatively little about at this time. In the long run, it would probably be better if the AMA rules change was to a straight 500cc (30.5 cubic-inch) displacement limit, without the 750cc side valve anomaly. Or, even down to a 350cc limit, which would be more in keeping with the trend in the rest of the world. It is fairly certain that if 500cc machines like the MVfour showed signs of proliferating, the FIM would abandon the 500 class. The MV is reliable, but it is a very old design and not very highly developed, producing at most about 65 bhp; and it is considered a bit of a handful even for a rider of Hailwood's caliber. Gussied-up touring motorcycles, with much less refined handling and brakes already seriously overworked at the speeds now possible, promise to be absolutely murderous when propelled by 80 bhp. If the displacement limit is raised to 45 cubic inches, the rules regarding frame and suspension modifications for Class C motorcycles will have to be greatly relaxed if the demands of safety are to be met. In the end, the intent of the Class C rules might be more nearly met if we adhere to the existing rules, or drop the limit to 350cc; it would do a lot for safety. •
