« previous next »
Pages: [1]   Go Down

Author Topic: Yz490 piston  (Read 2079 times)

0 Members and 1 Guest are viewing this topic.

Offline POM

  • C-Grade
  • **
  • Posts: 125
    • View Profile
Yz490 piston
« on: November 21, 2015, 10:39:59 am »
Does anybody know the difference between the 82/83 piston and 84 onwards?.......part listings on eBay seem to suggest their different.......
Logged

Offline tony27

  • Legend
  • *****
  • Posts: 1908
    • View Profile
Re: Yz490 piston
« Reply #1 on: November 21, 2015, 12:23:09 pm »
Likely to ring pin location, earlier motors are sideport like the 465s then then they changed to central exhaust port. Reed valve shape changed as well
Logged

Offline Rupert Prior

  • Novice
  • *
  • Posts: 6
    • View Profile
Re: Yz490 piston
« Reply #2 on: December 28, 2015, 02:45:39 pm »
there is a difference in the compression heights (pin to crown height). early is 40mm and late is 39mm, I don't know the point they changed and I have only seen it in after market pistons. it causes problems with the squish clearance, so the barrel has to be shimmed to match.
Logged
Pages: [1]   Go Up
« previous next »