Balancing full size locomotive wheels

[HopperParticipant @hopper]

Oh, yes. The WR/KR/XR race bikes were made by HD. Of course they used magnetos and carbs by others as per normal. There were some aftermarket parts available but HD pretty much scooped up all the best tuners and got them working for the factory on contract, eg Tom Sifton, Jerry Branch. Very very few people ever bettered factory performance on the track. And if they did, they were on contract to the factory the next season.

No, the rules did not exclude all others. BSA Gold Stars and twins and Triumph twins raced against them for years. Rules were that bikes had to be based on a production model road bike (so no Manxes etc) and 750cc sidevalve raced against 500cc overhead valve up to 1969, which were pretty evenly matched. The Goldies and Brit 500 twins gave the lawn tractors a good run for their money. But the Harleys did not blow up as often so finished more races and got more points. From '69 onwards the rule was all 750cc OHV on the flat tracks and the legendary XR750 was dominant within a year or two of development for the next four decades or more. Now obsolete, they are still the machine to beat. There were a few years of brilliant road racing there when the Tridents and Rocket 3s were up against the early XRs, with a few Honda Fours and Suzi waterbuckets thrown in. Then along came the TZ350 two strokes and it was all over on the roadrace side of things.

However, as you say, many of the top fuel drag bikes have barely a Harley part in them. All aftermarket stuff twice the stock capacity, twice as strong etc etc, blown, running on nitro etc. Those are all HD Big Twin based, a whole different family of bikes from the 750 true race bikes, which are related to the road-going HD Sportster family.

There's a lot more to Harleys than big fat guys puttering around on big fat bikes. But most of it happened in isolation over the other side of the pond so we never heard about it much in the Empire. Bizarrely, the amount of development put into the sidevalves is on par with what went into the Manx or the Gold Star, but over a much longer period.

PS, how did we get on to this from balancing loco wheels? Sorry for the thread hijack. Lawn tractors and steam engines are kind of a commonality though I suppose.

Edited By Hopper on 22/07/2018 11:37:09

Edited By Hopper on 22/07/2018 11:38:42

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