Those sleeve pinching ring/clamps are a joke. They out of round the cylinder and do not taper it at all. They leave some sides of your piston too tight in the sleeve then other parts loose. They feel tight but There is not a correct fit of the psiton/sleeve. Since RC engine rely on metal to metal sealing of the piston/sleeve if its not absolutly perfectly round. It will not run good and not last.

Resizing is not that much and the results are far superior.

Check out Rcrenew.com