GasGas power valve linkage problems

smb_racing · Mar 20, 2002

hello all,
I was bored, and since I couldn't do anything else with my bike now that it's half torn apart on the stand I decided to clean the powervalves. I took the cover loose (half gallon of spooge on my nice clean floor) and removed the left hand side powervalve very simply. The groove in the valve was clear full of carbon, leading me to believe that the bike should about kill me after I get the swingarm back on it. Removed the center flat valve and cleaned it, it was a tricky time getting it back in not having the jug apart. Then I go to clean the right hand side valve and I took off the small cover, took off the nut and washer that holds the linkage together, and removed the triangular shaped actuator. Well after realizing that you can't take that valve out that way I start to reassemble. While tightening the small 8mm nut that holds the linkage together I felt it give, I thought I snapped it off but it's not. It turns loosely like the stud has seperated from the triangular shaped actuator, but it won't pull apart and the linkage still does it's job fine. What the heck happened? Is the stud just a press fit into that actuator or does it thread in somehow? I'm baffled :silly:
Again thanks in advance for any help.

GlennP · Mar 21, 2002

First of all, you have to take the right side actuator plate off to remove the right drum and bearings for cleaning. The correct way is to work from the right side first. Its actually better to pull the cylinder and inspect everything anyway. If the valve is that dirty it probably can use at least rings. The older bikes also used bushings on the left side that may be replaced with bearings. The small stud is press fit into the plate with a knurled base. Mine broke loose also, and I spot welded it in place. It is a cheap part though (<$20).

On the SMS site, somewhere there is a detailed power valve service instructions. Do a search. If you come up short, call Jim or Sam. Unfortunately I have a hard copy only, or I would e-mail it to you.

smb_racing · Mar 21, 2002

Thanks Glenn, that's exactly what I needed to know. I took the actuator plate off and removed the roller bearing on the right valve, but when I went to remove the valve there's a seal of some type hanging it up so I gave up and reassembled, inspecting the valve through the exhaust port it looked relatively clean. I think the carbon is most the product of the poor factory jetting and poor maintenance on the part of the previous owner. The bike has excellent compression, but soon I'll have to replace the transmission gear that's bad and it'll get a complete rebuild.

sharp · Mar 21, 2002

And here you go!

As posted on the SMS forum.

1. Remove the left and right side powervalve (PV) covers. The PV linkage is on the right side.
2. Remove the locknut holding the PV push rod to the PV actuating lever plate.
3. Remove the allen head bolt that connects the PV lever plate to the right side PV assembly. Remove the lever plate and sleeve. You should now see the ball bearing supporting the right PV.
4. Remove the allen head retaining bolt and washer holding the right bearing in the cylinder.
5. Remove the left side retaining bolt and washer. Note: The left side has a sealed bearing and the ball bearings are not visible.
6. Insert a small diameter rod into either side retaining bolt hole and push the PV flapper pivot rod out the other side.
7. Screw the allen head bolt for the PV lever plate back into the right side PV assembly.
8. Using vice-grips or pliers, grab the head of the PV lever bolt and pull out the right side of the PV assembly. It should include the bearing, bushing, and the right exhaust transfer port valve. If you look into the right side PV, you will see the main flapper valve, and a control rod inside a hollow groove of the flapper valve.
9. Insert a small diameter rod through the flapper valve groove and tap out the left PV assembly. Alternatively, you can gently tap on the control rod that is sticking out of the flapper valve groove.
10. Remove the flapper valve through the exhaust flange.

smb_racing · Mar 21, 2002

thanks sharp,
I did pretty much everything backwards even though it worked out fine, but when I put the allen bolt back in to pull the RH valve it wouldn't budge, it operates freely though so I'm kind of wondering what the trick is?

alangraham · Mar 22, 2002

Gasgas Powervalve

Is taking the powervalve apart a normal service chore, and if so, how often should it be done on a 250 Gasgas. BTY, where is the SMS site as mentioned?

smb_racing · Mar 23, 2002

the SMS site is www.smackovermotorsports.com

I don't know how often it should be done, but my bike has been on this top end for a while apparently, and with the rich factory jetting it just builds up, especially if you trail ride a lot and the bike loads up. My valves were very carboned up, you can inspect them through the exhause port to see if they're too bad or not. A little maintenance never hurts though.

GasGas power valve linkage problems

smb_racing

Master of None

GlennP

smb_racing

Master of None

sharp

smb_racing

Master of None

alangraham

smb_racing

Master of None

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GasGas power valve linkage problems

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