I was riding my friends blaster and i relized it had power ban in every gear. When i went to wheelie it in first and secondit reved alittle and got loud. THe front went up a little but once i hit close to the top of the gear the front shot up. I was wondering if it is how yamaha makes all of there quads or if it is just because it is a 2 stroke.

 

People always think that you can buy a powerband or its something that only comes on specific quads, well.. A powerband is only on 2 strokes. Its not even a physical object or a mod. Its just an area in the top end of the RPMS in which the motor makes the most power. In some quads (like my banshee) it feels like its a whole different motor when its in the power BAND (not ban). But as far as I know, what I said is what it is.



NICK

 

DS650's got a nice powerband. When you hit the gas the motor reves up but somewhere around 4500 rpm it instantly just starts to scream and lift the front end as well. THis is a 4 stoke so i guess its not only with 2.

 

every quad , car ,truck, bike has a power band it just where the the power comes on .
in my truck its about 2300 rpm you can just fell it pull
as for the banshee you just fell it morebut all quads have a power band

 

True, all engines have what is called a "powerband".
It is simply the RPM range in which an engine produces the best power.

The "hit" is much more noticeable on the high performance 2-strokes, because there is a big "jump" where the bike starts making a great deal more power when it hits a certain RPM.

This hit (to simplify greatly), is when the return pressure wave from the exhaust is timed perfectly to cram the unburnt gasses back into the cylinder, acting somewhat like a tubo charger on a car. It shoves the unburnt gasses back into the cylinder just before the exhaust port closes, thereby cramming much more fuel into the cylinder to be ignited, which in turn produces a horse power jump, not unlike the "hit" on a turbo engine.

This is what is going on (quite simplified of course) when the quad feels like it wants to "rip your arms off".

 

I think that I like a two stroke powerband more than a four stroke powerband. Personally, I think that it is alot easier to get into(pull clutch, push lever, dump clutch, fly off the back; on a banshee). Four strokes have it everywhere, but all the power is spread out so far that it doesn't seem to have enough power.

 

2fun explained it well. Every engine has an RPM range where they produce the most power but on 4 strokes it is broader and doesn't occur as quickly. A 4 stroke in a high state of tune will have a more evident powerband that a mild one. Nonetheless, 4 strokes aren't typically referred to haveing a powerband in the typical sense of the word.

A 2 stroke, unlike a 4 stroke, uses the return pressure wave and suction created by the tuned pipe to scavange the cylinder of exhaust gasses as well as assist in the draw of air/fuel into the cylinder. The reason that you have a powerband is that the way the 2 stroke engine's port timing and pipe are designed there is sort of a resonant frequency in which this pumping action is in harmony - scavenging exhaust and drawing in a new air/fuel mixture. This is where the engine is the most efficient and the powerband kicks in. Bear in mind that this is largely a factor of the tuned pipe. Without a tuned pipe, this effect is significantly reduced. You'll notice that your weedeter or chainsaw doesn't have this powerband since they do not use a tuned pipe.

 

Well put WyoDuner.[img]i/expressions/face-icon-small-wink.gif[/img]