powervalve yz

[yamahopper]

i have heard that the powervalve stops on a yz250 can wear out and cause the powervalve to open to far and hit the piston. is this true and has anyone had any experience with it?

 

[ecy063]

power valve

On my 94 KX the valve holder can distort the head and allow the valve to close too far and hit the piston. I welded and reshaped the holder and seems to work well now. :ride:

 

[Rcannon]

i have heard that the powervalve stops on a yz250 can wear out and cause the powervalve to open to far and hit the piston. is this true and has anyone had any experience with it?

Yes, it is true. The older yz's have this problem. You can either replace the powervalve and stop (150.00) or grind a bit off of the powervalve to prevent this.

You'll notice a shiny spot on the front of the piston long before it does serious damage.