Powervalve issue?

[SpeedyManiac]

Hi guys,
We're having an issue with a 2011 EC250 (my girlfriend's bike). When we picked it up in March, the bike ran great. It pulled strong from the bottom all the way to pinned. All was well, but now the bike is really soft on the bottom then hits very hard in the midrange and pulls well through to revved out. At first I thought it was jetting, but after playing with that it seems to be lying somewhere else. A few people have suggested I check that the powervalve isn't stuck open, so I did.

The powervalve isn't stuck open and seems to operate okay. I did notice that when I had the idle turned up and the choke on, the powervalve mechanism flutters (actuating plate behind the right side cover rotates approximately 60 degrees clockwise). Once the bike was warmed up, the powervalve remains shut at idle but as soon as I twist the throttle, it opens about halfway, then at maybe 1/3 throttle the powervalve is all the way open.

To me, it looks like the powervalve is opening too soon. Any idea what RPM it should be opening and how fast it should open up?

[GMP]

I'll bet I know, sounds like my '03 was. Soft low end and a lot of rattle. The bellcrank setscrew is either loose, or the main adjustment is off allowing a large amount of free play in the mechanism. What is happening is the PV itself is just floating around under pressure of the exhaust pulses. You need to pop the side cover off and adjust out all the free play. Everything else in the PV system is set by mfg tolerances.

[stemplin]

This sounds like the same sypmtoms my 08 is having. Can you explain a little more what you mean by the bellcrank setscrew and which side cover you are referring to.

[toolmaker]

My 2011 has the same symptoms. It's been that way since new. I thought it was jetting also, but I've pretty much got it running strong.... all but the bottom end. I guess I didn't think about the power valve. Please explain what to look for and how to adjust it if that is indeed the problem.

[SpeedyManiac]

To get the free play out, do I need to shim the spring or adjust the position of the actuating arm coming off the governor? I checked and there's no loose screws in there.

[GMP]

Hold/jam the PV actuator plate up on the cyl closed.

Preload the PV governer spring with a .005" to .010" feeler gauge (not that critical). I used to do it by feel but this is easier and consistent.

loosen the setscrew on the bellcrank

Push/hold the governer assy fully into the case bearing, be sure its straight, and
tighten the setscrew

Remove feeler gauge and replace the side cover

The idea is to remove all freeplay and end up with just a VERY SLIGHT preload, so the actuator is held to the stop.

[shaheeb]

Can someone please explain or post a picture showing which part is the 'governor spring' where the feeler gauge goes? Governor Assembly?

I adjusted the pv actuater too tightly my first time around. the assembly was so tight that my top end was cut short, losing overrev.

I would like to do it right this last time. I dont know where parts fiches for gasgas is, this would help in identifying each part so I can follow what GMP means.

Thanks

[Jiikoo811]

Anyone else get pv stuck open proplems? First i think it because carbon, but it do that sometimes still after cleaning and new bearings.
Not big proplem, just rev up and it go back to life. Just like to know am i only one who had this proplem.

Sent from Razr MAXX

[thumperflipper]

My only input is I found that I bound the flapper valve (central exhaust valve) from pushing the left side bearings too far in. I wouldn't have noticed except I had the jug out doing a topend, then while putting the pv assembly together I bound the flapper. Pulling the bearings back out a mm (ish) solved the issue.

here is a video showing the problem:

http://www.youtube.com/watch?v=FQJs2qM3rT8

[andy176]

I took a look at the power valves today wen it idles the lever sits against the stop and it doesn't move til about 4k revs and wen I give it a quick rev they bounce open full and bounce back nearly like they are flapping about does that sound right as it doesnt seem right to me doesnt do it all the time tho. Also wen I rev the bike they either seem to b fully open or closed and they dont gradually open as the revs increase does that seem correct.? Also the bearing on the left side seems to move in and out wen I rev it does that seem right.? Im trying to fix a problem where the bike wont rev out. Thanks.