Riders of the Milwaukee marque entered the newly sanctioned class in the same manner as they had previously contested 1/2-mile dirt track events.  They simply removed one cylinder from their potent 61 cubic inch, 2-cam motor.  On the other hand, Indian fielded a special purpose, single cylinder 30.50 for this class of racing.

Indian's motivation for developing a 500 cc motor had originated in about 1920 with the onset of a down-turn in the motorcycle industry.  Since a significant percentage of Indian sales were for export, the Springfield company hoped to strengthen their sales position in Europe by mounting a challenge at the famous Isle of Man road race.  By international agreement the Isle of Man event was limited to the smaller displacement machines.

Charles B. Franklin whose Irish origins gave him a particularly keen interest in the British road race, experimented with various configurations of motors that would qualify.  Franklin's efforts came to fruition in 1923 when Freddy Dixon, aboard an Indian factory "special" finished in 3rd place at the acclaimed international event.  Two years later a 4-valve version of the same motor finally surpassed the H-D "half-twin," giving the Springfield company 4 out of the 5 National Championships contested in the 30.50 class.

1926 was notable for being the first year of official recognition for 45 cubic inch racing.  The popularity of the Super X, together with the Chicago company's influence in the industry-controlled sanctioning organization, forced official recognition of the class that was destined to become the mainstay of motorcycle racing in America.  In July of that same year, Joe Petrali rode a blistering 107.65 mph mile on a Super X at the Altoona, Pennsylvania board track, putting to rest any concern that the smaller motors would reduce the thrill of the still popular spectator sport.

The following month the first National Championship for the new class was won by Jim Davis who rode an Indian 30.50 to victory over the 45 cubic inch machines.  Although the Springfield company was not quite ready with a 45 of their own, Charles B. Franklin had been busy.  In July of 1926, examples of yet another Franklin-designed race motor made their first appearance at the Altoona, Pennsylvania board track.  In its earliest rendition, the new Indian racer appeared as a 61 cubic inch, side-valve twin.  At first glance the new motor resembled a Powerplus, but in fact it was an entirely new design.

Both camshafts as well as the crankshaft ran in self-aligning ball bearings and the combustion chamber was patterned after the Ricardo design.  One of two oil pumps fed the lower end, while the second pump pushed oil to the front cylinder.  At first glance, it seemed that Franklin's design had borrowed (and improved upon) the best features of the previously dominant Harley-Davidson race motors.

There were notable differences, however.  The most apparent was that the new Indian motor was a side-valve with detachable heads.  Each cylinder featured its own intake manifold and Zenith updraft carburetor.  The dual oil pumps, distinctive bronze timing chest cover, and twin updraft carbs gave the motor a snarly, purposeful look.  In its first time trial (in July of 1926), "Curly" Fredericks lapped the Altoona board track at 114 mph.  As a result, the new motor was immediately labeled the "Altoona," for the track where it made its debut.  If Indian had waited another month Franklin's latest design undoubtedly would have been called something else.

On August 21st, on the 1 and 1/4-mile Rockingham board track at Salem, New Hampshire, Fredericks won two 25-mile races (including a Championship) on his 61 cubic inch "Altoona."  Then Jim Davis led the Indian team (who were riding 45 cubic inch versions of the same motor) to victory in the 20-mile National Championship for that class.  During an intermission, Fredericks unleashed all of the power of the 61 cubic inch side-valve, completing a lap in 37 and 2/5th seconds.  This performance set the record for the fastest speed (120.3 mph) that would ever be attained by a motorcycle on a circular wooden track.

Another class of championship racing also debuted in 1926 with the introduction of 21.35 cubic inch (350 cc) National Championships.

Gene Walker's death, and Indian's subsequent proclamation about reducing the displacement for track racing had had its effect.  The official sanctioning organization of the sport, the AMA, announced that their purpose in introducing 21 cubic inch racing was to limit the speed on the half-mile dirt tracks.  The manufacturers were anticipating the new class.  Harley-Davidson had already unveiled their OHV 21 cubic inch racer (immediately dubbed "the peashooter") at a local race in Milwaukee, in August of 1925.

The idea for the H-D "peashooter" had originated in the early 1920's when the Milwaukee firm moved ahead with their decision to offer a lightweight model that would appeal to entry level riders.  While H-D's 37 cubic inch "Sport Twin" was in production at the time, the opposed twin was a complex engine and had proven expensive to manufacture.  Arthur Constantine, with William Ottaway's help, began work on a new design for a more economical lightweight.  Side-valve and overhead prototypes in both 21 and 30.50 cubic inch capacity were constructed, but only the 21 inch motor was initially put in production.

When the racing version of the new H-D 21 first appeared, there was no immediate challenge from their main competitor, but Indian was not far behind.  The Springfield company chose to contest the new class by designing an overhead-valve version of their recently (1925) introduced 21 cubic inch "Prince" motor.  The Indian re-design was successful.  By July of 1926, at the first national Championship race for this category, Jim Davis piloted the Springfield entry to victory, attaining a speed of 88.9 mph on the little Indian "peashooter."  For the opening "salvo" of competition in the 21 cubic inch class, the Charles B. Franklin-led engineering department had bested the Milwaukee sales leader.

When the final results for the year were tabulated, Indian came out ahead, victorious in 8 of the 12 solo National Championships contested in 1926.  With the distraction of a wide array of racing categories (21, 30.50, 45, and 61 cubic inch classes), and the fact that there was no longer any strong factory team identification, spectator loyalty gravitated to the brand that they rode.  If an enthusiast followed competition at all, he was most likely to cheer for local or regional riders who raced in nearby events.

In 1927, Joe Petrali finally captured a National Championship for Excelsior (the company's first such victory since 1916), winning the 10-mile, 45 cubic inch title for Schwinn's Chicago company.  Once again, the year proved most favorable to the Springfield company, Indian winning five out of nine National Championships.  Indian's success reiterated the technical excellence of Charles B. Franklin, whose "Altoona" motors now featured overhead-valves in 45 and 61 cubic inch versions and an 80 cubic inch side-valve model for that class of hillclimb.  Harley-Davidson victories were confined to three Nationals, all in the recently introduced 21.35 cubic inch "Peashooter" class.

All three companies were able to share honors in the popular hillclimbs.  Since the National Hillclimb Championship was still determined in a single yearly contest, spectators were more likely to value the outcome of their regional event.  The variety of Novice, Expert and Professional classes insured that everyone could claim some success.  At the 1927 Capistrano hillclimb, Excelsior's publicity focused on their victory in the 80 cubic inch novice class, while Harley-Davidson's PR department advertised their win in the 61 cubic inch "free-for-all."

For 1928, Indian's 45 cubic inch overhead-valve "Altoona" motor continued to dominate National Championship track events.  Contributing greatly to the Wigwam's "Grand-Slam" 1928 Championship performance were Jim Davis and "Curly" Fredericks.  Particularly notable, were the races held in August at the Rockingham board track in Salem, New Hampshire.  These were the last National Championship motorcycle races to be contested on the boards.

Jack Prince, the colorful and indefatigable proponent of the wooden motordromes, did not live to see the final year of the sport that he had so vigorously promoted.  The former high-wheel bicycle world champion died on October 7, 1927 of complications following prostate surgery.  The death of the 68 year-old board track impresario was a somber portent that the era that he had helped to create was coming to a close.

Following the closure of some of the early tracks in the teens (such as Playa del Rey in 1913, Chicago's Speedway Park in 1918, and Brooklyn's Sheepshead Bay in 1919), the 1920's bore witness to a number of other important track closures.  The Tacoma track had closed in 1921, and the Beverly Hills and Kansas City tracks in 1924.  The Laurel, Maryland track closed in 1926, the Culver City and Fresno tracks in 1927, and even the Rockingham track in New Hampshire had closed at the end of the 1928 racing season.