oversized valves

[330exracer]

im thinking about geting oversized vavles since im gettin a new cam and harding my rockers. how much gain will i get with the biger vavles?

[wyndzer]

If you are getting a bigger carb it will probably help a little. If stock carb, then don't waste the money.

[Houser Cannondale]

Ive heard from some engine builders that the ex has the same head from the 250x. the valves are definatly not too big for the 250 motor so when they put the head on the 300 its almost has too small of valves in stock trim. especially when you put a cam in it so if it was mine i would get it ported and get oversized intake valves also

thats my 2 cents worth

[Adams44]

On the 400ex, the carb is the limiting factor. The head pipe flows more air then the head and the head flows more air then the carb.

If you are going to do this with out increasing carb size, I would think your gains will be minimal. Once you go with a bigger carb, now your head becomes the next item to increase flow. Now you can port and increase valve size. I am sure by this point you have a larger head pipe.

Hope this helps.