Quote:
Originally Posted by Jeff Higgins
One of the older tricks in the H-D flat track arsenal is to re-set the cam timing (very easy on the XR750/Sportster platform) to make it run as a "Twingle". The Triumph, BSA, and Norton guys did this as well on their parallel twins. The parallel twins were turned into a "split single", or "twin single" ("Twingle") wherein both jugs fired together. The H-D's necessarily have a 45 degree split, but the idea is the same. Better traction on really slippery clay. I saw Chris Carr running this setup on his XR750 in Sturgis one year, when he was riding the local half mile while recovering from a broken leg. Very easy to pick his bike out of the crowd.
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Quote:
Originally Posted by Jeff Higgins
One of the older tricks in the H-D flat track arsenal is to re-set the cam timing (very easy on the XR750/Sportster platform) to make it run as a "Twingle". The Triumph, BSA, and Norton guys did this as well on their parallel twins. The parallel twins were turned into a "split single", or "twin single" ("Twingle") wherein both jugs fired together. The H-D's necessarily have a 45 degree split, but the idea is the same. Better traction on really slippery clay. I saw Chris Carr running this setup on his XR750 in Sturgis one year, when he was riding the local half mile while recovering from a broken leg. Very easy to pick his bike out of the crowd.
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The HD 'twingle would still sound odd
HD does use a 360° cranks like Dudacti but the cylinders are 45° out of phase
Norml HD firing pattern is 315-405-315, 'Twingle' is 45-675-45-675
Ducati and British vertical twin will be an even fire 360-360-360, 'Twingle version is the same
