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Reeds are simple little devices if you look at them. Just a funny shaped piece that most people have not a single clue about.

Think of a reed like a valve on a faucet. When the valve is open it allows flow, when it's closed there is no flow. You can also open the valve part way and only allow some flow through. While this is a very simple explanation, it really is how a reed works.

There are three types of reeds listed in order of quality, stock (metal), fibreglass and carbon fibre. Stock reeds are typically a thin metal. The reason they fail quickly is because metal has a memory and once bent it tends to stay bent. When you order a fibreglass reed you are getting something that is decent quality and possibly stiffer than a stock reed but which doesn't retain a memory. Carbon fibre is even stiffer than fibreglass. When a reed starts to wear out, it becomes less stiff.

A reed operates literally by flapping in the wind. As you open the throttle the reed bends to allow flow. The more throttle the more the reed will bend to allow flow. At the bottom end a stock reed is typically acceptable, but as you get into the higher RPM ranges a stock reed will flutter easily. So when you're riding your bikes and it sounds like it's having trouble running at high RPM's that is your reed fluttering. A reed that is flexible is good for bottom end response, but bad for top end.

So you step up to the next level and go with an aftermarket fibreglass reed. Since this type of reed is stiffer it will resist fluttering at the top end but is really designed for bottom end to mid range riding. There are higher quality fibreglass reeds but if you're going to move up to that class you might as well move on over to carbon fibre.

Going to the next step which is a carbon fibre reed, should consistently resolve any high end fluttering. However moving to this type of reed on a stock bike can limit throttle response at the bottom end since it's spring tension is so high.

A followup article will be written on dual and triple stage reeds and upgraded reed cages.

This article was written by Bruce Peresky for pocketbikeforum.com. Copying is permitted provided you give credit to http://www.pocketbikeforum.com

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