Powervalve issue?

[thumperflipper]

OK...after adjusting my powervalve as discussed in this thread twice and still having a very loud rattle on decel, I think I found the answer. My bike doesn't rattle any more. Sweet! Please review the videos below and let me know if there is a better way to keep the bellcrank from hitting the case. I can't change the length of the push rod but maybe some of you have a better or easier idea of fixing this.

Video 1 (making the adjustment):

http://www.youtube.com/watch?v=dI0fU...2UwnDw&index=2

Video 2 (bike running before and after):

http://www.youtube.com/watch?v=YGjVW...2UwnDw&index=1

[thumperflipper]

I guess a thicker base gasket stack may raise the cylinder and keep the bellcrank from hitting the case. But I replaced what came in the bike, a 0.5mm gasket only. My squish is 1.6 but my piston at BDC is 1.5mm. Overall I am happy with the way it runs here in CO, riding at 10,000 ft average. Eventually need to increase the base gasket stack and get the RB head mod. So what do you guys think? Is the bellcrank hitting and rattling a symptom of a thinner base gasket stack? I mean are the people that still have a powervalve rattle on decel (after proper adjustment) all running a thin base gasket?

[Jakobi]

That first vid with the vibey noise sounds more like my pipe does when the seals are blown out than the pv rattle.

[thumperflipper]

Agree, Jakobi, rattles definitely have lots of causes, and the powervalve always seems to get blamed first, but can't forget about other causes. Had this bike a year and it has always made this rattle. Tried new O rings a couple of times, no dice... untold hours on gasgasrider trying any recommendations from anyone to rid this noise... Just did a topend with new exh O rings (again) and holding pressure on the pipe with my foot has never changed the rattle.

my bellcrank was hitting the inside of the case at the same time the actuator plate was bottoming on the stop bolt at powervalve closed position. I think what was happening on decel is the exhaust pulses made the powervalve flutter (less tension from the governor spring as the PV closes). With the case cover off and the bellcrank unloaded I could replicate the noise by tapping the bellcrank on the case.

Rattle rattle rattle. embarrassing... bend bellcrank, no more rattle rattle rattle. Not embarrassed any more... thats all I know... did I mention I am stoked?

Let me add, I would have sold my gasser long ago if it weren't for you guys here on gasgasrider helping a brother out. Seriously, I owe you guys what I can never repay. Awwwwwww mush

[Jakobi]

You sound STOKED

[singletracker]

I just want to say thanks to everyone that posted advice, pictures and videos about the PV adjustment. The GG manual is pretty useless, and without the information provided in this thread I wouldn't be a happy camper right now.

History: I was happy with how my bike was running, but it had 100 hrs on the original topend so I decided it was time to freshen it up. I used all OEM parts and the same thickness base gasket, but somehow my PV got out of adjustment during the process.

After the new topend the low end was really anemic, and the bike had a hard hit into a strong topend. At first I thougtht it was the jetting since it was warmer than the last time I rode it, but the more I thought about I realized it reminded me of how my KTM ran when I had the PV pin fall out. Long story short...I made the adjustment to the PV, and now I have a very linear and strong pull from top to bottom.

Before I made the adjustment I was having to ride a gear lower than normal, but now I'm back to chugging up hills a gear taller again. BTW, the actuator plate was against the screw prior to the adjustment, but it would not stay there at an idle. After the adjustment it stayed there at an idle. Small adjustments seem to make a big difference!

[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.

[SingleTrackMind]

Originally Posted by 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

Yes I just cleaned my power valve because of the same issue. Only to find it's not because of carbon. It's the linkage or belcrank as mentioned in this thread. I haven't pulled my cover off to check it yet. The valve turns freely until the rod is connected. Then it hangs every other time when close to wide open. Same thing happens when I'm riding. When I get on the gas once in a while I can hear it hang up. A blip of the throttle usually resolves it.
This has happened since I got the bike new.