Cycle News - Archive Issues - 1970's

I Steve McLaughlin hates restrictorj i piates... and other things ~ 00 t"'O') 1""""4 By John D. Ulrich "The restrictor plates are pure , unadulterated crap!" shouted Steve McLaughli7 . "T hey have done nothing but restrict the privateer. " & McLaughlin stood behind an ironing board in his Santa Ana, California apartment , pressing a dress shirt and punctuating his speech with waves of the hot iron, Dressed in shorts and a tshirt , McLaughlin talked to a reporter while preparing for a nig ht on the town . He was very angry. Steve McLaughlin hates , among other things, the intake restrictor plates now required in 750cc GP machines raced at American Motorcyclist Association Camel Pro Series road races , "Four years ago, when this idea of using restrictor plates to slow the 750cc road racers first came out , Hurley Wilvert and I tested restrictors , The original restricror concept used a 2mm -thick ring between the carburetor and the intake manifold. We . quickly found that we could overcome any horsepower loss caused by the ring simply by adding streamlining in front of and behind the ring. It was obvious then that anybody working for a factory could beat the restrictors everyway but sideways , 16 "I _s~rye, ~s rjder_r_ep!esentative, on an AMA road racing""" committee, along with Bob Hansen as administrative advisor , Gordon Jennings as technical advisor, Gavin Trippe as promoter representative, and the AMA's Bob Rudolph , Bill Boyce and Douglas Mockett, the Czar/ Commissioner of Racing , "The original idea was that the committee would formulate and vote on proposed rules affecting road racing. But after Mockett was named commissioner, he informed us that we would 'se rve in only an advisory capacity, and that he would make all the final decisions. "We had several meetings on the subject of restrictors , and Hansen and I explained over and over again that the results of previous tests showed that the bikes would not go slower. "Personally, I felt that there was no need for restriction of the bikes at all . But I represent the riders as a whole, and arnajority felt that the bikes were going too fast and should be slowed down. So, as rep resent a tive of the riders, I was willing to go along with the idea of slowing down the motorcycles. "H ansen and I had an alternative plan to use of restrictor plates. We sug gested a rule based on an idea Wilvert and I worked out several years ago , an idea which would be equitable for everybody: lowering compression by making the combustion chambers bigger. By lowering the compression, you could get the speed decreases, run a smaller main jet, have less wear-andtear on the crankshaft , get better fuel economy and probably get Yamaha to eat the cost of . suppl ying us all with heads . The idea was simple and eas y. But Gordon Jennings said it wouldn't work , that it was impossible . "The last we heard at th e final committee meeting before Daytona , simple restrictors 2mm thick and 23mm in inside diam eter were to be used , which would have worked the same for everybody. But somewhere along the line before Daytona , Mockett decided to allow streamlining of the rest ric tors . "How well did the restrictor rule work at Daytona? Kenny Roberts , riding against a 35 mph headwind , qualified . 19 second slower than he did on an unrestricted bike in 1977 . During the final ra ce, he lowered the one -lap average-speed " reccrd-f :'ve times, on five separate laps. "W ha t happened to the 10% or 5% speed reduction the restrictors were supposed to produce? It turned into 0 % reduction! Five mot or cycles with connections to the Yamaha factory ran in the 170-180 mph range consistently, while th e. rest of the field ran in the 150 mph range. "My TZ , which for the last five years ran in the 170 -mph bracket unrestricted , ran 152 mph in the first two days of Speed Week . Where did I qualify? I haven't been out of the first three rows in four out of the last five years and I qualified 25th! Anybody who saw the Superbike race knows that I haven't forgotten how to ride. It was all the restrictors. I will sort out my bike and make it competitive sooner or later. But all that trouble and agony is for what purpose? The restrictors don't do what they're supposed to do . They're worthless. "The restric tor rule 'a c t u a ll y benefitted a small group of people, but not most of the riders . Who benefitted? Restricror manufacturers . The one manufacturer who beat us all, Yamaha . But Yamaha doesn't run the AMA , and they do a great service by making a state-of-the-art piece of equipment available at a reasonable price in the United States. They did what any racing organization would have done in a similar situation take advantage of the rules as incompletely administered by Mockett , "So, I don't condemn Yamaha, I don't condemn non -factory riders with factory components , I don't condemn Yamaha Racing Dir ect or Kenny Clark. I condemn Douglas Mockett , who made the fina l decision on the restrictor plates. " I personally trashed $2000 worth of engine parts at Daytona, Erv Kanemoto and Gary Nixon trashed five or six engines. Don Vesco and Gene Romero trashed a bunch of engines. Like the other privateers, I had no time to test restrictor plate configurations between the time the new bikes were delivered and the start of Speed Week. Unlike the factory , I had no time to adequately test the restrictors while running around having exhaust systems made , fairings put on , wheels manufactured and installed and all the other things you need on a serious racebike . So , like all the other privateers during Speed Week , I lost cylinders , crankshafts , engine cases and pistons. " A major problem with the restrictors, and the reason why many peopl e had problems with engine failures , was that the reduction of air/fuel flow altered the necessary gas / oil mix ratio . In effect, if the same gas / oil ratio was used after installation of the restrictors , the engine _was getting a smaller volume of air, less fuel and less oil at any given rpm . " Peop le couldn't understand why they were getting seizures with a rich , plug reading, which only reflected the gas /air fuel mix, not the gas/oil ratio or tota l fuel volume. In fact, they were running low on oil, and needed a stronger mix . Many people lost bearings and had seizures from la ck of lu b r ic a t ion . We dropped from a normal 28: 1 to 24 :1 gas /oi l ratio, and probably should have been running 18:1. One of my . friends joked that Gordon Jennings has been pushing 15: I oil mixtures for the last 15 years, and he's finally found a way to make us all use it. "T he big mistake Mockett and the AMA made in this whole thing was that they allowed everyone to do what s they wanted to do . They should have handed everyone identical restricto • given them all the technicaf information needed to make the.' work, and told them what to expect a far as oil ratio requirements an tuning went . That would have bee fair. ' 'i "As it was, a few people, a connected to Yamaha, had t ri restrictors and specia l rublje} manifolds and access to technica information that the rest of us didn't have , The results was that I watched five motorcycles completely dominate the race and decimate the. competition. With Kenny lapping ih " field, the restrictors certainly dido',t improve the racing. They didn't attract any spectators , either , as anybody who looked at the grandstands during the 200 miler knows. , "Yet one week after Daytona, in Caracas, Venezuela, I saw Kenny Roberts run fourth in the 500cc class until he retired , and I saw him have an exceptional 250cc duel with ,3 relativel y unknown Italian named Franco Uncini . Uncini led , Roberts passed him , Uncini repassed and left Kenny Roberts behind - until Uncirti crashed, All on unrestricted motorcycles. 10 "T he point is this: I believe th t Kenny Roberts is one of the best motorcycle racers on the face of tn earth , in all of history. There is no question about his talent. But hIS ta lent shouldn't be added to by evZrr advantage in the world, such as tri ck restrictors and a $200,000 motorcycle. The restrictor rule ended up jus giving Roberts more of a pre-race advantage by setting back all t~e privateers. As for the $200,000 motorcycle , that brings up another thing . "The AMA has long had a claiming rule, designed to keep people from entering special , factory-buil l 100 ,000 or $200,000 motorcycles ano totally annihilating the competitiorf: The idea was to keep the cost of bemg competitive within reach of all the riders , since nobody would enter such an exotic bike when somebody could buy it for a few thousand dollars after th~ race. . "Several years ago, the claiming rule was changed from covering the whole bike to just the engine, carburetion

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