The Colorado Mile
THE COLORADO MILE
TOM STRONGMAN
IT'S LONELY to be out front. Dick Mann, the current Grand National Champion, knows 1972 Point Leader Kenny Roberts knows. And at the Colorado Mile. Mark Brelsford and Jim Rice found out.
Brelsford showed up with one of Harley-Davidson’s new alloy 750s. Since winning performance can only be judged against the competition, the only thing anyone knew before the event was that the H-D had potential. Now, everyone knows it can win, as Breisford not only set fast qualifying time, and won his heat, but led the first seven laps of the race.
Breisford was alone, out front. He would have stayed there, too, had it not been for BSA-mounted Jim Rice. Rice, running one of the best races of his career, slipped by the leader and immediately pulled out a comfortable lead. By the end of the race, he held a half-mile advantage over Breisford and had lapped nearly the entire field of 20 riders. Kenny Roberts powered his Yamaha in for 3rd, followed by Mike Kidd (Yamaha) and Keith Mashburn
t get the win, but they a couple of significant points, new XR is reliable. And, the fact that they decided to Tí the oil coolers at Colorado, overheating is no longer a problem. Secondly, the speed to win is there.
When_:êm'weighs this fact with Dick O’Brièîtis St ¿temen t that the XR engine is nowhere near its potential power äfid when you consider that Bflfetord'sl-bike had only three hours rior to turning fast time, wmmngseenis inevitable.
The new XR engine retains the traditional V-Twin configuration, but that’s about all it has in common with its iron barrelled predecessors. Bore and stroke on the new millis 79.5mm by 75.5mm. Aluminum heads and barrels are used and the exhaust ports exit from the forward portion of both heads on the left side. The dual exhausts are fairly short and terminate in reversecone megaphones. > J
BRELSFORD SETS FAST TIME WHILE DEBUTING H-D's ALLOY 750, BUT RICE ENDS UP IN THE WINNER’S CIRCLE.
COLORADO
On the opposite side of the engine, two 36mm Mikuni carburetors deliver the fuel through moderately long intake manifolds. Both carbs are rubber mounted to eliminate the possibility of fuel frothing due to engine vibration.
Pushrod tubes are mounted externally on the right and pass from the crankcase to the cast alloy rocker box covers. The rockers are mounted on eccentric shafts which facilitate valve adjustment.
An unspecified amount of power is transmitted via primary chain to a large, wet clutch located on the left side of the engine. The gearbox js a four-speed urrrt^which is more than adequate for dirt use, but which may prove to be disadvantageous on the road race course as everyone else uses either a five or six-speed box.
Lack of an additional gear, though, is not as serious as it first seems because Harley offers five completely different sets of gears and 15 different low gear ratios.
Harley is on the move all right, and they can’t be counted out of the running as Brelsford is currently holding down the No. 3 slot in the AMA Grand National Championship points race.
The junior class was dominated by Steve Droste (Yamaha) and Scott Brelsford (H-D). Each won their heats. In the final, they battled furiously to the urging of the wildly shouting crowd. Drafting down the chutes, passing corn^flf^they put on quite a show. Steve came out on top despite Scott’s hanging it all oât in the turns. 1
For the most part, weather was accommodating. Strong winds brought threatening clouds across the distant mountains, dropping a few drops of rain during practice. But the gusting of the wind the rest of the day made the track dusty and dangerous. The sandy surface would soak up water and the wind dried the track so quickly that the corners started to break up after half a dozen laps. This made the final difficult for riders and spectators alike because the dust made watching painful as it was whipped into eye-searing clouds propelled by the wind.
Riders also had problems with the wind which rapidly changed direction,
compounding their troubles with the track surface. Not a soul left, however, as big time motorcycle racing had a hammer-lock on the 12,000 fans.
Incidentally, Pikes Peak Turf Club is a horse track which has not made a lot of money during the past few years, but the Yamaha Gold Cup changed that. It
was the first AMA National to be held in Colorado and it proved to be almost too much for the facilities. Concession stands ran out of food, spectators ran out of room and the security guards ran out of help. But it was worth it. [<5]
results
25 MILE NATIONAL CHAMPIONSHIP
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