theory behind the "cam mod"

2 replies to this topic
  • rpyfz450

Posted April 03, 2006 - 10:46 AM


Is it true that opening the exhaust valve earlier (like the WR450F) gives an engine more low-rpm power? I understand that closing the exhaust later increases overlap scavenging, but wouldn't opening earlier be wasting part of the combustion cycle?

I know two-stroke engines that have their exhaust ports open later gives more low-rpm power which is the opposite of what happens on four-strokes.

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  • rpyfz450

Posted April 11, 2006 - 05:04 AM


Are connecting rod lengths significantly different from 2-strokes to 4-strokes?

  • OlaGB

Posted April 11, 2006 - 06:28 AM


I think its irrelevant, since the results are depending on both cams..

The point is that the exhaust flow makes the intake stroke able to pull in more air when timed correct.. If you change timing on one cam, the other might have to be changed as well to make an effect..


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