i have a 400ex and i want to know why it keeps going through rings every month. i also want to know what the best pipe is for a 4ooex!

 

What do you mean by going through rings? How are they failing?

 

they keep burning out of the cylinder, causing my bike to puff out blue smoke!

 

um, rings won't burn out of the cylinder, they may break apart and end up in your engine oil. the blue smoke sounds like burning oil. Just to get this striaght are you saying you remove the cylinder once a month and put a fresh set of rings on the piston? if that is the case you need to have the cylinder bored to the next oversize and install the mathcing piston and rings.