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techtalk:ref:engmech04p [2020/10/05 04:14]
hippysmack [REF: Engine Mechanicals - Sub-07D]
techtalk:ref:engmech04p [2023/12/26 21:44] (current)
hippysmack
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 That's why racers with vacuum pumps use multistage scavenge pumps to account for the imbalance to scavenge and improve it. \\ That's why racers with vacuum pumps use multistage scavenge pumps to account for the imbalance to scavenge and improve it. \\
  
-Regardless, it's evident that some racers use vacuum pumps to increase vacuum pressure in the crankcase of a Sportster engine. ((Hippysmack of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=2073932)) \\+Regardless, it's evident that some racers use vacuum pumps to increase vacuum pressure in the crankcase of a Sportster engine. ((Hippysmack of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-motor-engine/​sportster-motorcycle-bottom-end/​197307-sportster-crankcase-pressure-engine-breathing-wetsumping-and-mods?​t=2073932)) \\
 It's been said that positive crankcase pressure upon piston upstroke gets between the rings and basically causes bad sealing at the ringlands. \\ It's been said that positive crankcase pressure upon piston upstroke gets between the rings and basically causes bad sealing at the ringlands. \\
 This is also in the high RPM range when ring flutter is present. So there are several things happening then. \\ This is also in the high RPM range when ring flutter is present. So there are several things happening then. \\