Power valve did it stick?

[mattdenn]

Hi Guys
07 gas gas ec250, owned for a year and always run and been reliable. At the weekend whilst riding on a uphill gradient the bike note changed and i lost power. The engine continued to run but the exhuast sounded rattly and although the bike still moved it seemed to have no power at all. After stooping and starting the bike seemed fine again. about an hour later it done the same thing. with a good handfull of throttle it cleared itself again. it then run the rest of the day o.k. anyone got any ideas what might be going on?
thanks

 

[GMP]

Classic dirty, sticking PV.

 

[mattdenn]

Thanks
Is it just a case of cleaning it? and does it mean complete disassembly of the powervalve?

 

[GMP]

Yes and yes. Good news with a GG is you can pull all the PV parts from the cyl without removing the cyl from the motor. R&R the main flap is easier with the head removed though.

 

[mattdenn]

Thanks Glenn
Never cleaned one before so it will be a sharp learning curve.

 

[gasgasman]

http://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fwww.gasgasons.com%2Findex.php%3Fsite%3Dstatic%26staticID%3D133

 

[mattdenn]

Great link, thanks.

I removed the exhaust and PV left and right covers tonight, all seems to be moving freely, does not seem to be sticking or any restriction, probably a different story when the engine is under load. Even though is all seems to be free i thinks it will be best to disemble and clean.
Have there been any issues on bikes with the mechanism in the side casing that controls the PV arm?
Thanks

 

[GMP]

Don't pull up on the PV rod, you can cause the balls to dislodge from the governer. Disconnect the rod first, then check movement. Heat the nut on the plate to soften the loctite.

 

[mattdenn]

Oh no, thats exactly what i did. How do i now if i've dislodged the governor bearings? should i fire it up? I was gonna start the disembly tonight to get the PV cleaned.

 

[mattdenn]

Hi
Tonight, i remove the exhaust valve lever from rod on right hand side and also the left and right bearing holder bolts. I then removed the long rod by tapping it throught from one of the bearing bolt holes. It then says to pull out the right hand exhaust valve (can be aided by screwing back in the bolt). this is where i am stuck, there is about 5mm play but the damn thing will not come out. should it come out easy or are the prone to be tight. any suggestions? i think it might be the bushing between the bearing and valve (right side) causing the problems.

 

[gasgasman]

Probably carbon build up on the rod. You can take another rod that is slghlty smaller and push it through.

The engine side cover has to be removed to reset the governer actuator.

 

[mattdenn]

Second attempt. knocked out the left hand side double bearings and valve first by putting a rubber coated handle up through the exhaust port and using a little brute force. Then knocked out the right side bushing, bearing and right valve by passing the rubber handle end of a screw driver through from the left hand side. now time to clean and re assemble.
This side is a great source of information.