KX Riders

Maintenance & Technical => KX500 Original => Topic started by: sawfly on February 21, 2016, 06:40:18 AM

Title: 1986 vs 1987 head
Post by: sawfly 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.

Title: Re: 1986 vs 1987 head
Post by: mun 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.

Title: Re: 1986 vs 1987 head
Post by: RoostDaddy 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.

Title: Re: 1986 vs 1987 head
Post by: mun 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.

(https://farm2.staticflickr.com/1526/25021111450_67eeb3cf90_o.jpg) (https://flic.kr/p/E82JHh)1986-87 KX500 cyl head_b (https://flic.kr/p/E82JHh) by MuN52 (https://www.flickr.com/photos/79390825@N02/), on Flickr
(https://farm2.staticflickr.com/1507/25290469526_339ac405ba_n.jpg) (https://flic.kr/p/EwQgu3)1988 KX500 cyl head (https://flic.kr/p/EwQgu3) by MuN52 (https://www.flickr.com/photos/79390825@N02/), on Flickr

Title: Re: 1986 vs 1987 head
Post by: motopunk on February 27, 2016, 05:09:08 PM

Quote from: mun 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.

(https://farm2.staticflickr.com/1526/25021111450_67eeb3cf90_o.jpg) (https://flic.kr/p/E82JHh)1986-87 KX500 cyl head_b (https://flic.kr/p/E82JHh) by MuN52 (https://www.flickr.com/photos/79390825@N02/), on Flickr
(https://farm2.staticflickr.com/1507/25290469526_339ac405ba_n.jpg) (https://flic.kr/p/EwQgu3)1988 KX500 cyl head (https://flic.kr/p/EwQgu3) by MuN52 (https://www.flickr.com/photos/79390825@N02/), 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..