Reeds, what are they for?

[mrputtputt]

what exactly is the purpose of the reeds in my 05 zuma? trying to figure out how they compare to a motorcycle. i see people buying aftermarket reeds, but i can't understand what the purpose is for or what the part does.

[downtown]

The reeds basically act like a one way door. As the piston is going up it is creating a vacuum and the reeds open allowing the fuel to enter the crank case. As the piston is coming down, creating pressure, the valve closes keeping the fuel in the crank case and is "pushed" up into the intake ports. Over time the can warp or even break (not good). When they warp the allow some of the fuel back through the intake and you lose power and in some cases will make the scoot hard to start. The stiffer the valve the quicker they will close at high rpm which is good but, you will lose some bottom end. Visa versa for thinner reeds. Hope this helps

[flynlow]

Also, people opt for the Fiber or Carbon Fiber instead of the stock metal ones to prevent cylinder damage if a piece were to break off.

[mrputtputt]

hmm... as a result of modifying the reeds, does anything else need to be modified to compensate? for example, many aftermarket exhaust require some roller/spring change. for reeds, rejet?

thanks for the explanation. i'm not as familiar with the 2-stroke world. haven't heard of reeds even on 250gp/1250gp racebikes.

[downtown]

Changing the reeds w/carbon fibre, stock steel, fibreglass should actually be put under the label of regular seasonal maintenance. they are not like adding a new pipe or vario in that putting them in will not affect anything, but you will feel like the scooter is more throttle responsive


Dt

[hunter]

Hi some scooters don't have reeds so what will happen if I take them out will the engine still run in my zume

[j~scoot]

will the engine still run in my zume

If your scooter is designed to take reed valves it won't run without them. Some scooters don't have them because they have a different design that uses the crank to induct air/fuel. If you have reeds you need them to regulate the induction.

[FreakyBeanie]

Since we are talking about reeds i have a question. I just got some stage 6 carbon reeds. took of the stock ones (they are like new motor only has 1500km) and when i install the carbon reed i notice that there is a small gap between the reeds and the reed cage (size of a paper page approx) on the opposite side of the bolts to secure the reeds. My question is that normal for carbon reeds? I know when the motor runs there will be a positive pressure in the base before the vacuum occurs but will that small gap be a problem? I'm also installing a new 21mm arreche carb so to simplify the tuning it would help to be sure that the reeds won't cause a problem. and just a note: the reed cage is good and is super clean. Thanks

[Bender]

I lost an engine to a small piece of metal from a broken reed that got into the engine. Lucky it was still under warranty. I then changed them to carbon right away.

[zeonsredcomet]

To address what bender just posted: THAT IS EXACTLY WHY NO MATTER WHAT YOU GET RID OF THOSE STUPID STOCK METAL REEDS AND GO CARBON FIBER.