KDXRIDER.NET

i always read a lot about the kips, reeds and flywheel. i really don't know what they do. the reeds have something to do with airflow and the kips kick in when you need it but other than that what do these things do, a heavier flywheel makes your powerband smoother or something, this is my first thing with a motor that i've worked on so i figure i should know what everything does. thanks in advance

The KIPS helps extend the powerband of the engine. It works by changing the combustion chamber volume. The reeds are a method of controlling the amount of air/fuel mixture entering the combustion chamber. The other method for 2 stroke motors would be a rotary valve. A heavier flywheel helps keep the engine from stalling by storing some of the energy that is produced by your engine and giving it back to help keep the engine going when it starts to lug down.

-Maurice

Good Pictorial about how KIPS work on CDaves site...

http://justkdx.dirtrider.net/kips.html

Also some other "tech" info there you might want to look at Parker.

Reeds help the motor run better by keeping the mixture from becoming overly rich when the piston motion causes a backward pulse in the intake. Without them, some of the mixture would flow back through the carb and get richened by the addition of more fuel on the next intake phase. A four stroke doesn't have this problem because the intake valve closes and prevents back-flow. Some cheaper two stroke motor designs don't worry about it and just delete any control system like reeds or a rotary valve.

Here is some general info.

K. I. P. S. = Kawasaki Integrated Powervalve System

There have been several versions for KX and KDX over the last 20+ years. Look at the buykawasaki.com diagram of your cylinder, then look at the diagram of a 1985 KDX200. See all the missing parts? That is your version (1995 - 2006 KDX) of the K.I.P.S. Besides what morie said, it changes the compression inside the cylinder at various RPM's, which alters the power delivery.

The reed valves or reeds, open to allow the fuel vapor to enter the engine.

A flywheel gives it inertia. Since you are one of those darn BMX punk kids imagine this. What is easier to start spinning, a spoked wheel or a solid steel wheel? Which is harder to stop? The flywheel weight helps to keep the engine spinning.

Here's a general tip: If she won't crank, check for fuel, air and spark.

btw....

Depending on your internet connection speed and how long you let it run, CDave's KIPS animation gets the graphics and descriptions mixed up. It says one thing while it's showing a different...thing.

There is a KIPS description in the front of the service manual.

I see references to volume and compression changes (not static compression btw..not a matter of total volume divided by compressed volume). The movement of the main exhaust port leading edge (part of what the KIPS does) changes the timing of a 2-stroke engine. No..not spark timing. Where the ports (all of them..intake, transfer and exhaust) are situated as far as the piston covering/uncovering them is what determines the port timing of a 2-stroke.

Changing the port timing of a 2-stroke is similar in effect to changing a camshaft in a 4-stroke.

Consider the different configurations of reed cages, reed composition, tension and you can see there are many choices to be made in that regard, too!

re: Reeds and A/F charge flow:
My Duster (V8 4-stroke) has positive manifold pressure at idle. Does that mean I need to change the reeds?