Harry Klemm’s “The DG Years, 1975-1976” – Episode 12: A Few Words About Engine “Formulas”

During the 70’s, there was a growing abundance of “so called” engine formulas that were claimed to let you easily calculate the ideal port timings, compression ratios, expansion chamber dimensions and carburetion. Even before my days at DG I had made countless attempts to use these formulas while building the many different road-racing platforms I was working with. Despite the lack of positive results from the formulas, I still held hope for them.

But could this help a YZ125 get the holeshot at Saddleback?

The 1976 125 DG team bikes were the result of countless hours of “cut and try” testing. By the end of the 1976 race season, the DG race team Honda and Yamaha 125s were arguably some of the fastest 125s in the country and I had all the technical data. So, I decided to try to work the formulas backwards by plugging in my final engine specs, and worked to see how the formulas had to be “tweaked” to deliver the final data that I knew worked best. What a disappointment. While some of the formulas got somewhat close, not a single one delivered the final specs that I knew worked best. After that frustrating and time-consuming experience, I pretty much abandoned all the formulas, and instead relied on my experience, my existing data and good old ‘on track” testing. It’s what worked.

Story Index (Click on any title to read the episode)
Episode 1: Understanding The 70s SoCal Motocross Atmosphere
Episode 2: My Road Into Motocross
Episode 3: Getting a Foot in the Door
Episode 4: Reality in the Race Shop
Episode 5: Building a Race Team
Episode 6: Building the Team Bikes
Episode 7: Understanding the Goals of a Racing Business
Episode 8: The DG Front Office
Episode 9: The Competition
Episode 10: Painting the SoCal Racer’s Atmosphere
Episode 11: From Mechanic to I.T. Before There Was I.T.
Episode 12: A Few Words About Engine “Formulas”
Episode 13: Mechanic Buddies
Episode 14: 1976 Turning Points at DG
Episode 15: Facing the “Race-Gas” Era
Episode 16: The Retail Chamber Birthplace
Episode 17: The Mammoth Motocross Classic
Episode 18: The DG/Saddleback Launching Pad


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