my friend has a 03 kfx400 and he wants to get a bolt on 440 kit comes with cylinder and piston and all. also he bought the cams and he got to reading the cams and they told him they he has to use the cams with the stock piston and stock springs. well i was under the impresstion that you could put the 440 kit on with the cams and with aftermarket spring. Thanks

 

id call the company he bought the 440 kit from and ask them whats up.