So I pulled out my plug and adjusted my valves today and my plug is nasty and black so of corse I replaced it. What causes a black plug my $00 burns a little oil would that be the cause? Also does any one know if you can replace the balljoints on a 400EX??

 

my oil burners make the plugs black..lol

the ball joint appears to be pressed in to me,but on oem parts look up it only sold attached to the a arm..however I have some 250x arms that the lower ball joints appear to have been cut off and replaced with L shaped ball joints that bolt through the tube after the originals were cut i can email pics if u like

 

it could also be running rich

 

valve seals are bad to leak after a few years does it smoke at startup? ball joints are non replacable on stock arms. you can get a whole set used on ebay for under $100 or so.

 

Valve seals / guides will leak on startup and compression deceleration causing smoke.

 

From what you are saying it might be the valve seals but it smokes when youu reve it up not when you let off . Thanks for the info i have made a bid on the A-arm that I need.