THIS IS BECOMING A PRETTY POPULAR MOD TO THE 400 EX. I HAVE A FRIEND WHO MY BE LOOKING AT THIS OPTION. HIS BIKE HAS A LOT OF HOURS ON IT AND IT MAY BE ON ITS WAY OUT.

WHAT IS THE PROPER WAY TO DO THIS? I KNOW THAT CERTAIN THINGS CAN BE DONE TO MAKE IT RELIABLE, AND CERTAIN THINGS CAN BE DONE TO MAKE IT HAUL A$$. HE'D BE LOOKING FOR SOMETHING RELIABLE.

WOULD A STRAIGHT PISTIN CHANGE BE THE BEST OPTION? OR WOULD YOU NEED TO MAKE OTHER CHANGES IN ORDER TO KEEP IT RELIABLE. NOW I KNOW IF YOU DO VALVES AND ALL THA GOOD STUFF YOU OPTIMIZE THE PERFOMANCE, BUT YOU ALSO LOSE THE RELIABILITY, IF ITS NOT DONE RIGHT.

LET ME KNOW--

well, ive heard several opionoins on this, but the one i tend to go with is to bore it a 416, add a cam, maybe some port work, and ignition, cvarb if you can afford it, this in addition to pipe filter etc. major problem with the 440 i was told is blowing head gaskets since there is only 4 head bolts, unlike the old 350x which had 6. im planning on this summer going with a 416 high compression (12 to 1 at least) mild porting, and cam change. if i can swing it carb too.