When I installed my new piston I noticed the Rod was discolored and looked as if it got hot at one time did anyone ever noticed this on their 400ex as well has anyone ever Damaged their Rod with the mods they put on? I notice they recommend putting a heaver Rod with the 460 big bore kit anyone ever do this???

 

i think my friends looked discolored to now that you mention it. however, i wouldn't worry about it now. i do think they recommend running a heavy duty rod with more than 11:1 compression though.

 

..Yes the rods do look like that. If i was going to do anything over 13.1 or 440 plus and planed on keeping the bike for a long time,id put a rod in it. And also with a stock rod on a built motor i wouldnt run a high rev box. After time the rod streaches and lets go.

 

Sparks reccomends changing the rod with a 440 or bigger.

 

11:1 is the highest you can go with a stock rod, discoloring is normal. The only reason I upgraded my connecting rod was because the stock one was knocking ($200.00 for rod and machine work)