Modifying the engine to produce different powerbands (4T)?

[knockout_bar]

I'm not planning on trying it, but is it possible (just out of curiosity)? I know that different shape cylinder heads (the inside bit, can't remember for the life of me what it's called) change engine responses. Do different bores and strokes produce different characteristics? Exhaust/inlet ports? Titanium valves? Things like that.
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125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee)

[craigs23]

Might be wrong on this, but I wouldn't have thought so. Most 4 stroke engine modifications just increase/smooth out what is already available. Many 4 strokes have a sort of power band - but I presume this is just down to noise/emissions laws (deliberate flat spots/low power introduced to get through tests).

The only sort of power band I can think of is that of the VFR800 - where at around 7,000rpm it runs from a 2 valves-per-cylinder setup to a 4 valve one.

[Kickstart]

Hi

Lots of things affect where the engine produces power. Combustion chamber shape, number of valves, valve timing, carb sizes, inlet lengths, exhaust design, ignition timing, bore and stroke, etc.

Juggling around with the exact revs each of those are optimised for will affect the power delivery. Get it all to work perfectly at (say) 10000rpm and you will probably have a massive hole in the power delivery at 5000rpm (half peak power, at which point a lot of the things you have changed which rely on resonent frequencies will be doing the opposite of what you want).

All the best

Keith
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