What Might Cause This To Happen?

[PinHead]

I have never seen one just fall out ??? It is real easy to replace but it is quite strange that it just fell out.
Is the rubber from that seal brittle like it has been overheated or something ?
Either way it is time to call the dealer and put the order in for a new seal that they should have in stock but don't.

[Kham]

that sucks man.

[TLRMan]

Make sure all your breather tubes are clear, and not kinked....
Too much crank pressure can blow out seals.

Re-adjust your clutch before you condemn it....most of the time it's just out of adjustment, and needs to be snookered up.
You know where I live.......and coffee is always within an arms reach!

[Rye]

Mark is right but I can tell you from experience the clutch pushrod seal on the zx's are a POS. Either the crankcase pressure builds too heavily in these bikes or it is an inferior seal. My guess is too much pressure. The seals are the weak link in the system and given that Kawi uses a poorly designed 1 way valve off the crankcase to the airbox (that only actuates when crankcase pressure exceeds airbox pressure) I'd say that's the culprit. Wait 'til the countershaft seal blows.

[Kham]

soon?

comon get a 10r.

[Kham]

oh and if you get one of those undertail pipe bike, the after market cost for those are double.

[Mad Max]

Originally posted by Rye
...The seals are the weak link in the system and given that Kawi uses a poorly designed 1 way valve off the crankcase to the airbox (that only actuates when crankcase pressure exceeds airbox pressure) I'd say that's the culprit. Wait 'til the countershaft seal blows.

Wouldn't the negative pressure of the airbox mean that the crankcase pressure is always greater than it as long as there is more pressure in the cases than whats outside of them?

[cyberxen]

oh and if you get one of those undertail pipe bike, the after market cost for those are double

Less crap to scratch up and have to replace in the event of a mishap...

[Rye]

Originally posted by Mad Max
Wouldn't the negative pressure of the airbox mean that the crankcase pressure is always greater than it as long as there is more pressure in the cases than whats outside of them?

Since when is airbox pressure negative? That zx7 is making positive pressure (above ambient) at 70mph, best in the business besides the zx9. The one way valve is basically a little ball bearing that "pops off" when crankcase pressure is higher allowing the pressure to expel into the airbox and combusted. This is likely at lower speeds. At higher speeds the pressure in the box is greater. This is where the weak points in the system will feel their greatest stresses (seals). I run to a catch can (vented with a breather) and completely block the port to the airbox. This serves a few purposes. Catches any oil puke and condensation which can find it's way into the airbox. Increases crankcase volume by the size of the can and 5/8 tubing (gotta be at least a 10-15% volume increase). Breather allows for the + and - pull with engine pulses. Ideally, the system should be evacuated using a 45 degree fitting to the exhaust header. This has the effect of purging the cases with the exhaust flow. But does not make pipe sniffers happy.

[Rye]

Originally posted by Mystery Squid
Thanks everyone

So Rye, tell me about this countershaft seal? Where is it, and when can I expect it to blow?

Look at you picture. See that sprocket....right behind there. clean that crap outta there BTW. Just keep you eye peeled for leaks. The clutch pushrod seal is easy to diagnose. When you take that clutch slave off, there is usually oil in there.....it should be bone dry. BTW, cable tie the slave cylinder incase you depress the clutch and push the piston out of place....same concept as a piston in a braking system. These are two common trouble spots for the zx7. But can be a DIY project.

[Kham]

hehe.. i guess it is you. THE SQUID.

overfill and that's why dealer service sucks and the parts counter saleman sucks. they dont check the little window. every fuckin sales guys in the dealer says 3.x something and that would overfill. it's 3.0 exact for mine.