Four Stroke power bands

[Ariel Badger]

Recieved this from a friend regarding what is refered to as freak timing, I thought it interesting.

Freak timing is masses of overlap where you stop the inlet charge from going staright through and down the exhaust by setting up back pressure form for example the reversing pressure pulses in a megaphone silencer. These are brought about by the conitnuous change in section that occurs with a cone shaped megaphone without which the wilder cam timing wont work. Two strokes do the same trick with their exhausts though not using the same shapes. You end up turning a perfectly rideable adequately powerfull bike into a very noisy unrideable thing that produces much more power but only in a narrow rev band, "hence the phrase coming onto the mega". You also get loads of unburnt fuel going down the exhaust , back through the carb on your leg etc etc. Yes it is possible to overtune something.
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