PowerValve Flap removal technique

[FFRDave]

Last nights misssion was to remove and salvage all of the PowerValve bits fron my busted EC 250 Cylinder.

Here is what I learned: 1) You can tap the PV barrols out from the inside of the exhaust port with a small diameter punch after you remove all three of the little alen head bolts.
With the Exh port facing forward I found the back side of the Lefthand side barrol and tapped it out tword the left. I did the same taping right on the Right hand side barrol.

What I dont know is how to get that Flapper out. I tried and tried to look at it from every angle with a LED flashlight. I pulled on it a bit with my fingers and moved it in every direction, but still have no clue as to how it gets separated from the cylinder.

 

[Brian VT]

What I dont know is how to get that Flapper out.

I forget what position it needs to be in, but it will come out. You just need to keep twirling it around (no easy task) and trying.

 

[iancp5]

Last nights misssion was to remove and salvage all of the PowerValve bits fron my busted EC 250 Cylinder.

Here is what I learned: 1) You can tap the PV barrols out from the inside of the exhaust port with a small diameter punch after you remove all three of the little alen head bolts.
With the Exh port facing forward I found the back side of the Lefthand side barrol and tapped it out tword the left. I did the same taping right on the Right hand side barrol.

What I dont know is how to get that Flapper out. I tried and tried to look at it from every angle with a LED flashlight. I pulled on it a bit with my fingers and moved it in every direction, but still have no clue as to how it gets separated from the cylinder.

Just remove all the bearing bits. Mine just fell out with a gentle tap on the cylinder. Then if the rods the flap pivots on are still in there use an old nail or anything to just gently push them through. The flap will now come out into the cylinder - well it does on the 300. Should be really easy. Course a 250 may be a smaller port, not sure, but they got it in there!

 

[GMP]

The right side drum valve and bearing can be pulled from the cylinder by threading the bolt back in and grabbing with pliers. The left side is then eaisly pushed out from the right side. After the rods are removed, the main flap is rotated and turned sideways and can be removed through the exhaust spigot. It will come out easy in the right position, do not force it.

 

[FFRDave]

There seems to be a pin...

There seems to be a pin that runs across the inside front of the cylinder. It looks like the flapper pivots on this pin. It looks like a pin because there is a small diameter hole on each side of the cylinder. If that hole had a pin in it (running between those holes), it would be a perfect pivot point for that flapper.

GMP That flapper doesnt move side to side or diagonaly at all. It only flaps open and closed, but pivots.

Yessss !!!!

It was a pin after-all. There are two pins. One goes between the barrols and through the back of the flapper, and the other crosses through the front of the cylinder and provides the hinge (or pivot point) for the flapper.

 

[d2w]

There's a write-up in the Tech Articles section of this site on how to remove and service the Power Valve.

 

[Boomhauer]

Here it is.

http://www.gasgasrider.org/html/pv_disassembly.html

 

[eff]

It would be nice to have a MattR version with photos! Hint hint!

 

[GMP]

Next week I'll start my teardown and top end job. I'll take photos. I may not have time to put together a formal tech presentation, but photos are no problem.

 

[eff]

I need to do my top end this year and that would help a lot. I did my Honda once before I sold it and the GG is different.

Tricks like melting the nyloc nut are really important to safe some headaches and heartaches.

Thanks.

 

[MattR]

Next week I'll start my teardown and top end job. I'll take photos. I may not have time to put together a formal tech presentation, but photos are no problem.

That would be great if you could take some pics.

The step-by-step instructions that Uwe Hale did is adequate, but with your pics to supplement it would be complete. It shouldn't take too much work afterwards to link these photos with the previous instructions.

 

[HydroDog]

After the rods are removed, the main flap is rotated and turned sideways and can be removed through the exhaust spigot. It will come out easy in the right position, do not force it.

Can you be a little more specific on the flapper removal?
I got everything else removed but I can't get that flapper out of the port. Do I have to push it back on top of the piston to turn it sideways?

 

[MattR]

The step-by-step instructions that Uwe Hale did is adequate, but with your pics to supplement it would be complete. It shouldn't take too much work afterwards to link these photos with the previous instructions.

Here is the revised PV Disassembly article.
http://www.gasgasrider.org/pv_disassembly_mattr.pdf

 

[GMP]

You can remove the main flap without removing the spigot, as the spigot is the widest point in the exhaust tract. Just get it in the right position and it slips right out. If there is a lot of carbon or a rough spot in the casting this could make it harder but it should still come out.

 

[HydroDog]

Thanks Glenn for the reply but I'm still having no luck. My exhaust port is real clean and I reached in thru the side valve holes to scrap the sides of the flapper off but still no go. I even turned the flapper upside down and it's not coming out. Maybe I'm just one of the lucky one to have the port casted a little small. It's about .060" smaller than the spigot.

 

[Brian VT]

I'm lol 'cuz I've been there. Don't kick the dog ! He doesn't know how either. lol
I wish I could remember which way it needs to face to come out but it does so easily when you turn it right. I can't remember because I instantly ran to the fridge for a celebratory beer. You're gonna just shake your head when you have it out and in your hand.

 

[PEB]

If I remember right, after the pins are pulled drop the valve down a bit and turn it length wise should come right out. It definately can come out the front and does so lenth wise.

Paul B

 

[HydroDog]

I'm lol 'cuz I've been there. Don't kick the dog ! He doesn't know how either. lol

Man do I feel bad. After beating the dog to a bloody pulp and throwing the cat across the garage, PEB comes up with the winning answer.
Drop the piston down below the port, push the flapper up on top of it and turn it sideways and it falls right out.

 

[GMP]

Sorry, I assumed you had the cylinder off, much eaiser that way.

I delayed my top end rebuild as mine is still fine and I have had no time to ride and break in new parts before a race in wet sand this weekend(not a good idea on a fresh top end). I have all the parts so likely next month and I'll shoot some photos. I also bought a neat little tool for installing piston pin clips I'm anxious to try out.

 

[PEB]

It seems like i have taken the flapper out with the piston up, but who knows. Glad you got it out. Glen, Those d#$% little clips give me fits. Sometimes they jump right into the little groove other times ( like a couple weeks ago) it takes me numerous trys to get the thing in. I like to hold the rings in place with the jug while puuting the clip in. Tell us how the tool works and maybe post a pic of it.

Paul B

Paul B