cr 250 -not kicking into power band

[clutchcargo]

It's a pain in the ass, but it must be done. Mine stuck open once and I lost the bottom end of the powerband. Follow the instructions for removal of the valve. The 2 butterfly valves come out through the exhaust port. You have to rotate the pieces while you're pulling them out. I use a small hook to get them out. Then decarbon everything with a wire wheel and carb or brake cleaner. The carbon does not come off easily either, so you'll have to work at it. Reinstalling them is a bigger pain. Have patience!! After you have it back together, then readjust your cables. As far as cleaning intervals, it depends on how much you ride. I generally ride mx tracks. So I usually clean the valves about every 4 rides. If you start to feel down on power a little, then you may want to clean them. Removing the cylinder doesn't really make it any easier, except that you don't have to sit on the floor and look up the exhaust port.

[waynarky]

I just took the exhaust off and took a look up there with a torch. I pulled the flap valve shaft out and the flaps fell down but I can't seem to work them out the front.
They do look pretty dirty.

How do u do it?

[clutchcargo]

You can use long nose pliers to try and grab them. Then you have to flip them over and mess with them to get them out. That is really the hardest part. Trying to line them up. There's a left and a right side and they are not interchangeable. And use a flashlight instead of a torch, it is a gas engine!

[waynarky]

didn't see your earlier reply. Thanks man, I'll try that now.

[waynarky]

LOL. We call flashlights torches in South Africa!

[waynarky]

LOL, we call a flashlight a torch in South Africa!
Talk about living on the edge!

[waynarky]

I can't get the flaps out the front! I've pulled and fiddled and they won't get past a point. Tried using pliers & wire but they won't come down. Whats the trick?

I have pulled the shaft out so they dropped down. I don't remember what position it was in when I took the exhaust off but the left side of the pulley was up. I turned the pulley by hand and the flaps did move. How smooth should it be? It turned without too much effort but there was a bit of resistance .

[clutchcargo]

You have to flip them upside down and rotate them. As far as I know, there isn't any specific way to get them out. Maybe Honda has a procedure for their mechanics, but I sure don't know what it is. Just keep messing them until they fall out of the exhaust port. As some point you will question if they even come out, but they do. You have to get the correct angle and they will usually fall out. I think that the pointed part of the flap has to be toward the center {inside} of the exhaust port. Also, clean the shaft. If you have the cables disconnected, then the flaps should move up and down without any resistance. It doesn't take much for them to stick. A little tip when reinstalling them, rotate the piston so it blocks the exhaust port. It will keep the flaps from falling into the bottom of the cylinder{top of the crank}. If they do, don't panic. You can fish them out with a wire hook or something.

[waynarky]

How do I rotate the piston? Is that the piston that i can see behind the flaps? I thought it was a plate or something protecting the actual piston. I hope I haven't scratched the piston trying to get these things out! That could cause big trouble right? It is up at the moment.

[clutchcargo]

Ok, When I say to rotate the piston, I mean that you should use the kickstarter to bring the piston up or down so it blocks the flaps from falling into the cylinder. Yes that is the piston that you see. Do not damage the piston! If the flaps are still in place, use the kickstarter and slowly move it with your hand until it blocks the exhaust port. Then remove the flaps. You can try to jiggle the flaps around with a hook or something. {a rod made out of a piece of wire coat hanger will do}. When you get the right angle, the flaps will just fall out. Also make sure that you remove the rod that hold in the flaps and clean that also.