97 XP Exhaust valve leaking

[thepantydropper]

OK so this may be a simple question to some.I'm not new to riding but am sorta new to working on my own ski.I noticed the black plastic cup that has a clip on it on top of the motor is leaking a bit of oil.I had to look it up to even figure out what it was.I took the clip off and noticed it has some sort of seal in it with a spring around it.The seal looks pretty rough which would explain the oil leak.I found the replacement parts ok but my question is would someone please be kind enough to explain a bit further the function of this part and anything I should know before replacing it.I'm including this picture to show you what I'm talking about but this one is not mine just a pic I found.

 

[kicker]

That is your Rave valve (Rotax Adjustable Variable Exhaust) It regulates the exhaust flow. When rpm's go up and the pressure in the exhaust ports build up, the exhaust pushes against the spring and the valve slides up making the exhaust opening bigger.

here is a good thread on how to service them.
http://www.seadooforum.com/showthread.php?37588-How-to-service-Rave-Valve-Pictorial

This is how it is explained in the manual
For a 2-stroke-cycle engine to have high power capacity
at high crankshaft speeds, a high volumetric
or breathing efficiency is required and the fresh
charge losses must be minimized. The result is
achieved by opening the exhaust port early and
utilizing the resonant effects of the tuned exhaust
system to control fresh charge losses.
When an engine of this design is run at a medium
speed, efficiency falls off quickly. The relatively
high exhaust port effectively shortens the useful
power stroke and because the exhaust system is
tuned for maximum power, there is a large increase
of fresh charge losses. As a result, the
torque decreases along with a dramatic increase
of the specific fuel consumption. Higher torque
along with lower fuel consumption can be obtained
at lower engine speeds if the time the exhaust
port is open is shortened.

BTW, what is with that name, really?

 

[thepantydropper]

HA thanks for the help that helps alot! As for the name its from the show "East Bound & Down''. Kenny Powers named his jet ski that.Anyone who hasn't seen the show doesn't get it.Guess I should change it.

 

[donkey]

here it is,,friggin cracks me up!

 

[Minnetonka4me]

Its usually the black Orings on the shaft that get super hard and allow the leaking. If that doesnt solve it, a new base and valve are in order.

Also...if you run premix...its pretty hard to keep them from leaking. Lots of excess oil.

 

[thepantydropper]

HAHA thats right Donkey! Best show ever hands down

 

[donkey]

http://www.youtube.com/watch?v=LI8x94EVQ7E&feature=player_detailpage
i laugh so hard every time i watch this! sorry for interruptin ur post