Fearless people do not become successful motor racers. They lack judgement. Without fear, they do not recognise their limits or those of their equipment.

Two motorcycle champions feel the limits may have been reached in the 36th annual 200-mile road race at Daytona Beach (Fla. Speedway) today. Barry Sheene of England believes tires are not ready for the 200 miles per hour reached on the track's long straightway. American Kenny Roberts feels the 52-lap race should be shortened or something done to slow the pace.

Two years ago Sheene came off his machine at 175 miles per hour at Daytona when the rear tire tread peeled. He survived, as many motorcycle racers do, somehow. Improved rubber compounds and tread design have been the single greatest contributor to the dramatic increase in auto racing speeds. But, Sheene feels they haven't developed enough for the bikes.

The 200-mile race record at Daytona is 108.7 miles per hour with about half the race run over flat, squiggly turns at low speeds. About half is run at full speed, on the high-backed track. Motorcycles travel almost as fast as the stock cars did last month.

Sheene will miss today's event because his machine isn't eligible, not because he has been frightened away.

Roberts will be among the 80 starters because the $65,000 race counts toward the U.S. Grand National title that he has won twice.

The race has not been shortened, but some efforts have been made to reduce speeds. The major one was the addition of a chicane, a sharp kink in the track, at the end of the straightaway forcing riders to brake for it, ride slowly through it and enter the banked homestretch turn at a relatively low speed.

Roberts will race because he must, if he is serious about regaining his championships. "But, I want everyone to know I am not happy about it, " he was quoted as saying.

Motorcyclist survive some horrible crashes, protected only by their helmets and leather suits. Some feel it is because they are thrown clear of their machines and, if lucky, do not hit trees or fences.

This was the theory held by European auto racers for many years until it was determined a car driven was safer was safer with his car rather than flying through the air. American drivers led the way in using seat belts, helmets and fireproof uniforms.

Following Dayton's championship race are two more major motorcycle road events over shorter courses that its 3.87 miles. Two days of action at Charloote (N.C.) Motor Speedway is scheduled next weekend. On Saturday, April 2, the Long Beach (Calif.) Grand Prix course will be used and Barry Sheene will compete.

Both these circuits are less than 2.5 miles around. Both races are for 750 cc. (45 cubic inch engines) bikes, most powerful road machines now competing.

Local motorcycle road racing begins on the April 16-17 weekend. On Saturday and Sunday, road racers are at Summit Point, W. Va., for a meet featuring a 300 kilometer (186 miles) marathon.

Flat track racers will compete April 17 over the Laurel (Md.) Raceway in the opening Eastern Regional Championship race of the year.