2003 yz250 top end rebuild
  • yz250dude
    Posts: 6
    hi everybody this is my first time taking apart and rebuilding a top end and i was wondering if i need to replace my cylinder head. I ended up burning a hole through my piston. my cylinder is fine, however there is some residue from the piston burnt onto the cylinder head. i was hoping to not have replace it! would this be something i can just clean or scrape off? it is only in the middle partimageimage
  • yz250dude
    Posts: 6
      sorry i tried to upload a pic but im not sure how to do it lolimage
  • NZriderNZrider
    Posts: 5,081
    i usually just scrape all that melted aluminium off the cylinder head, be very careful not to scratch the sealing surface and try to smooth off any sharp edges in the combustion chamber. 

    then figure out why your piston melted and fix the problem so it doesnt happen again
    *********************
    Winning is 90% rider and only 5% bike, the rest is luck
  • Maple Leaf MXMaple Leaf MX
    Posts: 12,821
    What do u use to scrape the alloy off bjorn? And notice how i said alloy :/
    Expect to die whenever but dream to live forever

    ..the good times on the old DR board will never be back! RIP!
  • NZriderNZrider
    Posts: 5,081
    lol notice how i said aluminium. depends how melted to the head it is. if its not too melted ill use an old flat blade screw driver. its not too sharp so wont dig into the head material very easily. but if the material is really melted on there you might need something sharper like a cold chisel.
    *********************
    Winning is 90% rider and only 5% bike, the rest is luck
  • Maple Leaf MXMaple Leaf MX
    Posts: 12,821
    Im to chicken to ever use anything metal to clean my head. I prefer oven cleaner and a stiff brush. (Dont read my first sentence pervertedly) And what is aluminium bj?
    Expect to die whenever but dream to live forever

    ..the good times on the old DR board will never be back! RIP!
  • Maple Leaf MXMaple Leaf MX
    Posts: 12,821
    Aluminum + titanium = aluminium :)
    Expect to die whenever but dream to live forever

    ..the good times on the old DR board will never be back! RIP!
  • NZriderNZrider
    Posts: 5,081
    Aluminum is bad american spelling of a an element in the periodic table. see here Aluminium
    *********************
    Winning is 90% rider and only 5% bike, the rest is luck
  • Maple Leaf MXMaple Leaf MX
    Posts: 12,821
    Owned
    Expect to die whenever but dream to live forever

    ..the good times on the old DR board will never be back! RIP!
  • yz250dude
    Posts: 6
    thank you for the input! wouldnt i have to be pretty careful with the type of metal i use when i scrape it off? also i also double checked my cylinder and there actually is some on the walls as well... please i just posted another discussion today, please help lol
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