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Xr80r cylinder head

Posted: Tue May 18, 2021 9:45 pm
by xxweldonxx
Hey all, my son and I are rebuilding an 1986 xr80 with a 1996 xr80 motor. I purchased a new spark plug (ngk cr7hix) and found it was to small as it slides into the cylinder head. The spark plug is listed as a 10mm and I had a 12 mm that threads right in. I looked on the side of the cylinder head and it's stamped KA8-2 but I can't seem to find any info on it. Anyone know what kind of cylinder head this is? My only idea is to get a spark plug one size bigger ngk dr8hs.

Thanks
Levi

Re: Xr80r cylinder head

Posted: Wed May 19, 2021 8:22 am
by JimDirt
That spark plug (dr8hs) is not shown to fit any year XR80 ... so that part in itself is strange , it shows it fits 90cc bikes

Image

Source: http://www.transcanimports.com/download ... 0Honda.pdf

The strange thing is , everything I find with KA8 seems to fit a XR100 ... Maybe Ken has more insight to this ... send him a Private Message and see if he can come up with anything ... ....... https://www.crfsonly.com/forum/memberli ... rofile&u=3 Go to where it says PM: Send Private Message

Re: Xr80r cylinder head

Posted: Wed May 19, 2021 2:54 pm
by Aussiecrf230
I think the XR100 head fitted on an XR80 but you had to watch the valves didn't hit anything.
If I remember correctly people did swap barrel and head for cheater motors.
That is a life time ago though.
Like any build always make sure everything turns over and the vavles have a millimetre clearance, that's 40 thou in the old language.

KA8 is the product code for XLS100 1982-1985 if that helps.
KA9 was XR100 1981-1984.