1JKOO code

[xtrider]

I've got a question , one of my extra heads that I had gotten with a box of parts for several XT motors has the letters 1JK00 on it instead of 34l00 that is on all others ,but It was on a 600. The 550 has 5YI00 and TT's are 34K00. The thing about it is the chamber is smaller like it's a small cc version. Installed on a 600 would raise compression a point over stock. Everything else is the same as the 34l head , same bolt pattern as the '84 thru '87 XT's , the ,88-'89 has an extra bole and 2 of the studs are spaced wider.

[xtrider]

Note now, I must be going loony here(big surprize),was real tired last night, so decided to go look at my other bikes numbers and I guess the ''88-'89 are these 1JK's , the 34L's are '84-'87's, 2kf's would be those off 3tb motors, I also now see my new E-start motor has the 34L00 head/cylinder but that I knew I had used the cylinder/head off an older motor ('85ish),so it has the small chamber plus a high comp piston, no wonder it needs an awfully strong battery to turn over and runs real strong I also can't keep my head gaskets sealed and now have a solid copper gasket for it, this explains it.

I was under the impression the all the chambers for the 600's are the same, guess not. I'm now wondering which ones are used in the TT's .




the 1JK00 , 95mm wide , which is just a little smaller than my 2KF one,from '88-'89's, but not by a whole lot.



the standard 34L00 is about 90-91mm wide , which would give them higher comp.




this means anyone wanting to get a little more out of a motor should use the 34L head(and cylinders due to head bolt spacing changes), this is also where the newer bikes lost power and it was thought had to do with carburetor changes or size.


.

[Joly]

Hi,
Would a 1jk00 head fit on 3aj barrels and would the compression ratio be changed from a 2kf head?
Thanks,

I have a 3aj barrel and I want to upgrade my 1vj Tenere to improve the cooling.

Jolyon.