Salt and pepper plug?

[t3mp0r4ry nzr]

hi all!
me 96' cr125 has a tan colour on export port side of plug and carbony colour on intake side. Does anyone have an insight as to why this is? my figurerings are that the exhaust side, naturally, is hotter than intake side, but why?
is this common?

[gixxer-king]

ok first, during detonation/ignition intake is closed and then exhaust opens towards end of the stroke. with a valve closed it dissipates heat and so shares that intense heat with the rest of the head. however now your piston travels up and is pushing a still burning mixture up and past the exhaust valve this is open and can't share its heat with much. also the heat is not only on the face of the valve but now around and behind it, hence the discolouration of the valve face.

carbon on the intake should be cleaned off and is a hint (if in large quantities) that something aint quite right in there usually,

hope this helps

[t3mp0r4ry nzr]

yeah not really a good indicator is it. how do you know what the jetting is like when the plug indicates both good AND rich.

I stripped it down and the piston had ring blow-by on it. Slipped a new ring in and will keep an eye on it. Maybe just lacking compression.It will be interesting to see if I will need to make any jetting changes due to the greater compression and if the plug looks any different