cylinder ?

[pc500rider]

i have an 86 kx500 the cylinder has no scoring and measures stock readings but has discolaration lighter in some spots and darker in others does it need to be replated or will it be fine to run like to find out befor i buy new piston thanks

[Friar-Tuck]

PC,
  What have you tried to clean the cyl up with?
              I don't remember seeing any significant discoloration other than flaking of the Nikasil.  There is a distinct color difference in plating when it first gets chipped off.
 If it was run a while with flaking It will tend to blend in where oil has burnt past flaked off lining.  Can you catch a fingernail or pick in the transition from light to dark?
      Something You may consider is a ball hone or scotchbrite to clean up the old girl.
 I have repaired an old Jonsereds chainsaw from the early eighties that had been in a flooded basement 15 yrs ago.
   After scrubbing up the cyl. it was still in great shape. Unfortunately w/out a good photo most guys won't want to give you a bum steer and have a melt down.
    You may be able to get an honest answer from a machine shop, sorry PC.

[hughes]

Pictures would help. Could be oil glazing or plating flaking off as friar tuck stated.

[Friar-Tuck]

  PC,
 Is there anything in this thread that looks familiar ?

http://www.kxriders.com/forums/index.php/topic,6890.msg52529/topicseen.html#new

  Or can you find some pics that do resemble your situation?
 Tuck\o/

[pc500rider]

PC,
  What have you tried to clean the cyl up with?
              I don't remember seeing any significant discoloration other than flaking of the Nikasil.  There is a distinct color difference in plating when it first gets chipped off.
 If it was run a while with flaking It will tend to blend in where oil has burnt past flaked off lining.  Can you catch a fingernail or pick in the transition from light to dark?
      Something You may consider is a ball hone or scotchbrite to clean up the old girl.
 I have repaired an old Jonsereds chainsaw from the early eighties that had been in a flooded basement 15 yrs ago.
   After scrubbing up the cyl. it was still in great shape. Unfortunately w/out a good photo most guys won't want to give you a bum steer and have a melt down.
    You may be able to get an honest answer from a machine shop, sorry PC.

thanks for the reply i cant catch any thing with my fingernail i used a ball hone helped alot  still a little discoloration but not bad thanks for the advice

[RoostDaddy]

Sounds to me like it's just the glazing on the sleeve.  Cant see it being Nikasil flaking, as you said it is an  '86.  I'd just give it a hone before installing the new piston and you should be set.

[kwakman]

the 86's are nikasil and they do flake.

[RoostDaddy]

the 86's are nikasil and they do flake.

Interesting.  I guess you do learn something new everyday.  I thought the '86s were sleeved, sorry for the mis-information.

[kwakman]

i think the 85 model was too, not sure, but the 86's definitely are,mine is.hth.

[Goat]

85 is also nikasil plated