Can you tell me if this is normal for piston ? pic inside

[500bigbore2k7]

My piston has scuffs on one side of it and the cylinder has the same scuffs on it to is that normal ?  Is there anything i can do to remove the scuffs from the cylinder wall ? Is there any thing special i need to do before i install the new piston and rings ? My compression was at 90 psi when i tore it down, what should  the compression be around when i put the new wiseco kit in it and will it be much faster ?? thanks

[Platypus]

105-164 psi...found that info in someone elses thread.

[dcollins4328]

It sounds like it has been a while since someone did a top end.  I might recommend that you get your cylinder resleeved with nikaseal, and then put a new piston and rings in, otherwise you will wear out the new ones if you put them in a worn out cylinder.  It cost Big $$ though

[500bigbore2k7]

i looked at the cylinder again and it seems to be come right off when i rub it, its more like grime than actual scuffs in the piston and cylinder.  do i need to re hone the cylinder or what can i scrub it off with ?  Also how do you get the torque specs right on  the 4 nuts on the bottom of the cylinder when i put it back together. i had to grind  a wrench to get enough clearance to get the nuts off. thanks

[Polar-Bus]

i looked at the cylinder again and it seems to be come right off when i rub it, its more like grime than actual scuffs in the piston and cylinder.  do i need to re hone the cylinder or what can i scrub it off with ?  Also how do you get the torque specs right on  the 4 nuts on the bottom of the cylinder when i put it back together. i had to grind  a wrench to get enough clearance to get the nuts off. thanks

It's impossible for us to diagnose the severity of your cyl. scuffs without actually looking at them. Generally I tell people if you can feel them with your fingernail, the cyl is junk and needs to be repaired. That piston you have pictured siezed from dirt.

[KXcam22]

500,
  Those scuffs resemble a massive cold seizure but I am not positive since a cold seizure usually puts scuffs on the 4 corners of the piston.  Intake side sezures are usually lubrication based. As Polar suggested it could be dirt, but in my experience dirt usually takes out the rod big end or the main bearings first (but not always).  I wonder what oil the previous owner was running or if a tank got in that had no oil.  I would attempt to hone the scuffs out by hand with 400 wet&dry with some WD40 as a lubricant. Clean it up best you can before judging whether you need a replate.  If there are scratches or gouges under the scuffs then you will have no choice.  I would suggest you look closely at the rod big end bearing for signs of grit or marks on the rollers (magnifying glass) and carefully roll the crank to feel if the main bearings are smooth. Hope this helps. Cam.

Seizure cause list:

heat (lack of cooling, air leaks, lean mixture)
lubrication (oil based)
contaminants (dirt, bad gas etc)
no warm up before WFO (stupid based)