FILTHY power valve

Rebuilding the top end with a new cylinder on a 01 cr125. The exhaust valve flaps are completely covered in carbon. Thick carbon. I have had it soaking in carb cleaner for about 2 hours with very little results. Should I let it soak or is there a better way? Thanks!

Brake clean or equivalent contact cleaner and a wire brush...

Soak the parts is sea foam overnight. You can easily clean them after that.

Solvent works great, take it all apart and soak.

Do you have access to a sand blaster? Takes all of 2 or 3 minutes to have them sparkling clean..

I have never found any solvent to be of use.  Wire wheel is what I use.  Maybe a torch too.

Sandblaster works great

Easy Off oven cleaner.

Wire wheel on my bench grinder works every time. Just don't use the real stiff one.

Soaked then in sea foam for about 24 hrs. Didn't do much good. I'm going to try my dremel on low with a wire brush. My concern now is how thin the walls of the flap is where the shaft comes through. ImageUploadedByThumper Talk1392215636.110618.jpg

And this little "dip"

ImageUploadedByThumper Talk1392215687.577342.jpg

Is it time for new flaps?

As was mentioned earlier, hose it down with oven cleaner and let it soak for a bit. Most of the carbon will wipe off

Tried the oven cleaner last night with a little heat. Worked great!!

Tried the oven cleaner last night with a little heat. Worked great!!

Make sure to do it in a spot with good air circulation, preferably outside if possible.  The fumes that come off that stuff are horrible.


I use easy off for carbon build up on everything including cleaning your exhaust.  Be careful with anything made of aluminum though.  It will eat right through aluminum if you don't give it a good wash with soapy water afterwards.

Edited by c-slak

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