Author Topic: 1986 vs 1987 head  (Read 3605 times)

0 Members and 1 Guest are viewing this topic.

Offline sawfly

  • Newbie
  • *
  • Posts: 4
1986 vs 1987 head
« on: February 21, 2016, 06:40:18 AM »
will an '87 head fit an '86 bike? i'm having trouble finding an '86 head and someone mentioned that the 86-88 heads will work but the PN's are different.

Offline mun

  • Full Member
  • ***
  • Posts: 58
Re: 1986 vs 1987 head
« Reply #1 on: February 21, 2016, 10:27:37 AM »
You can use 86-88 cylinder heads and cylinders with each other.

I do not remember whether the various year models of cylinder heads volumes of small differences, but it does not matter if you drive a standard motor. However, the tuned engine you make changes to the cylinder head.
87-88 cylinders an additional exhaust ports a recess to facilitate the start-up. Otherwise, the ports are almost the same.
1986-88 cylinders exhaust ports adjustment is only an additional ports.

Was fairly difficult to translate into English. I hope you understand this.
« Last Edit: February 22, 2016, 09:17:19 AM by mun »

Offline RoostDaddy

  • Sr. Member
  • ****
  • Posts: 445
Re: 1986 vs 1987 head
« Reply #2 on: February 26, 2016, 02:57:41 PM »
86/87 heads will fit each other. I believe if you want to use an 88 you may need to change the head studs as they are different. If memory serves me 86/87 were shouldered studs 88 isn't. Hopefully somebody with more knowledge of the older style motors will chime in to confirm.
America is all about speed. Hot, nasty, bad-ass speed.

Offline mun

  • Full Member
  • ***
  • Posts: 58
Re: 1986 vs 1987 head
« Reply #3 on: February 27, 2016, 10:09:16 AM »
RoostDaddy, you're right.
The cylinder head studs must be replaced, or can also to machine 88-cylinder head the recesses.

1986-87 KX500 cyl head_b by MuN52, on Flickr
1988 KX500 cyl head by MuN52, on Flickr

Offline motopunk

  • Hero Member
  • *****
  • Posts: 1,150
    • www.der-motopunk.de.tl
Re: 1986 vs 1987 head
« Reply #4 on: February 27, 2016, 05:09:08 PM »
RoostDaddy, you're right.
The cylinder head studs must be replaced, or can also to machine 88-cylinder head the recesses.

1986-87 KX500 cyl head_b by MuN52, on Flickr
1988 KX500 cyl head by MuN52, on Flickr


... but that is an easy to made machining to fit
the 88 head to the 86/87 cylinder . could be made carefully with a drilling-machine ... 

but as long to the other diferences..  86 and 87 head are complete the same. the 88 has a diferent squish for the 88-2004 2ring-piston and is designed for lower compression.  86 and 87 had single ring flat top pistons..
big 2 stroke bikes are weapons for real men, who don´t fear death or devil. ;O)
´83 kx250, ´87 kx250 (with 360 big bore), 87 kx500, ´93 kx500 sfc

---  www.der-motopunk.de.tl  ---