What would cause this?

[steve181]

so i was out ripping on my moms 400ex ( lol i know)

and i hit a little mud hole, and the header came unbolted? ( enough to where it would wiggle quite a bit, so when i got home i took the wrench to it and it was been fine ever since

Edit: the bike was recently rebuilt by a guy i know, he does this stuff for a living and he does a very good job, and i do not think he would make an amature mistake and forget to tighten them down

[fishnfergie]

I wouldnt rule him out for tightening them, everyone makes mistakes. But other than him not tightening them vibrations could and I emphasize could loosen them.

[siggy konowaluk]

vibration?

[boost190]

(to above post) internal balancing or not (which 400's are)ridged mounted motors still vibrate a little ,not sure if it would loosen the exhaust thou,maybe if it wasnt fully tightened to begin with.:)

[slightlybent47]

The header gasket is a crush type gasket and it probably just crushed down some more, and the fact that it went through some heat cycles after the rebuild. You may want to pull it off and check to see if the gasket is still there.

[speedfreek]

Originally posted by fishnfergie
I wouldnt rule him out for tightening them, everyone makes mistakes. But other than him not tightening them vibrations could and I emphasize could loosen them. x2 everyone makes mistakes