Thread: gpr800 head
01-27-2009, 05:25 PM #1
ok i got my hands on a set fo 1200 riva rec heads. they bolt up and fit but i have a few questions
1 has anyone ever ran 1200 heads on a 800? the 800 and 1200 use the same size piston so shouldnt this fit???
any info on these heads at all would be helpfull
Last edited by yz450f; 01-28-2009 at 08:25 PM.
01-27-2009, 05:29 PM #2
Hey YZ you have a build thread why dont you ask all your questions in that thread instead of starting a new thread for every question. Keep it all in one thread that way we can keep track of your build.. 2 cents.
01-27-2009, 05:31 PM #3
i try but not many people look on my build thread.
but ok ill do that from now on.
01-28-2009, 08:27 PM #4
we still havent come up with a good answer
the 1200 and 800 have same size piston
here is a pic
anyone tried this before??
01-29-2009, 06:28 AM #5
As i recall the piston in a 800 is 80mm and a piston in a 1200 is 84m
But not 100% sure.
01-29-2009, 07:50 AM #6
800 and 1200 are 80mm bore ,1300 are 84mm,1390 are 87mm ,thay all run the same 78mm stroke !!!!!!!!!!!! standard that is!!!!!!!
01-29-2009, 03:06 PM #7
01-29-2009, 03:45 PM #8
i tried them and after torqing them down i slowly turned it over and it sounded normal
then i put in the spark plugs and still normal
i took them off and there was a ring around the head like the outside so im not even gonna bother
800 motors need 800 heads plain and simple
but im going to milll my stock head un less anyone has a cheap head for sale for a gpr800 66e motor
02-01-2009, 08:42 AM #9
Look in to the group-k they have a kit for about 500. Subpose to help all around proformance. Maybe be cheeper if you have some of the kit already.
PS: My 1998 gp1200 says 84mm I also found this info
This is a WSM Yamaha 1200 GP high performance piston kit - Kit includes rings, pins and clips.
size available:STD 84mm
02-01-2009, 08:43 PM #10
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