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]

Originally Posted by FFRDave

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]

Originally Posted by 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.

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 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.