Interchangeability of cylinder heads

[crazy88]

Are the heads for 1100 and 1200 interchangable? Or all years of the 1200 interchangeable? Might be replacing my head. Mostly can only find 1100 heads. And the one descent looking one from a 1200 is from and 86 apparently with a engine code of 38Y00, mine is a 1990 with engine code 36Y00. Visually they all look the same. Idk if there's and small variations. My shop manual doesn't having any information that would suggest they are different. Can't get a clear answer from Google. If anyone could give me an affirmative yes or no on the subject, I would greatly appreciate it.

[Billy Bananahead]

AFAIK they are all the same but if you need more reassurance then forget Google and use something like this > https://www.cmsnl.com/yamaha-motorcycle_model16707/  which will give you all the part numbers you need. It's European but covers bikes in the USA too.

[RPM - Robert]

Are the heads for 1100 and 1200 interchangable? Or all years of the 1200 interchangeable? Might be replacing my head. Mostly can only find 1100 heads. And the one descent looking one from a 1200 is from and 86 apparently with a engine code of 38Y00, mine is a 1990 with engine code 36Y00. Visually they all look the same. Idk if there's and small variations. My shop manual doesn't having any information that would suggest they are different. Can't get a clear answer from Google. If anyone could give me an affirmative yes or no on the subject, I would greatly appreciate it.

Yes, they are all interchangeable. You can even put the xjr1200/1250/1300 heads on with a little bit of shaving to the outer fins of the head. The 1100/1200s were in perimeter frames where as the xjr1200/1250/1300 were in a spine back chassis so they didn't take the time to machine the tape in those

[crazy88]

Awesome guys. Thank you for the responses

[Millietant]

Are the heads for 1100 and 1200 interchangable? Or all years of the 1200 interchangeable? Might be replacing my head. Mostly can only find 1100 heads. And the one descent looking one from a 1200 is from and 86 apparently with a engine code of 38Y00, mine is a 1990 with engine code 36Y00. Visually they all look the same. Idk if there's and small variations. My shop manual doesn't having any information that would suggest they are different. Can't get a clear answer from Google. If anyone could give me an affirmative yes or no on the subject, I would greatly appreciate it.

Yes, they are all interchangeable. You can even put the xjr1200/1250/1300 heads on with a little bit of shaving to the outer fins of the head. The 1100/1200s were in perimeter frames where as the xjr1200/1250/1300 were in a spine back chassis so they didn't take the time to machine the tape in those

Are there any minor differences between them, or any advantages to using a particular model of cylinder head (I'm thinking about my 3CV with a 1350 big bore kit). I'm not after ultimate horsepower, but like Pat am aiming for most usable real world power and torque heavy, with around 140 bhp.

[RPM - Robert]

No, they are all the same internally. The only difference being the outside fins and at some point on the 1250/1300 models they have EGR ports on the top side of the head for emissions.

[Bones]

What about the cams Robert, I've read where some say the 1100 cams have a different profile and are sportier than the 1200, but then read elsewhere that they have the same part number so are all the same. Has anyone ever measured the profiles between them and confirmed they're the same.

I know the XJR 1200 was a detuned version of the FJ, it was tuned to have more torque down low and less top end HP. Not sure how they achieved that, cam timing maybe?

[RPM - Robert]

It may have been a run of cams that got out of spec but they are all the same as far as I know. The XJR was never offered in the states so I don't know what they did to them but the cam gears are non adjustable and the part numbers are the same.

I have a set of 1200 and 1250 cams here and the lift is the same and the duration appears to be the same on them even though the prefix in the part number is different. The XJR could just be peppier because it is 75lbs lighter than the FJ 1200 series. This could be true for the 1100 as well as it was about 85 lbs lighter than the 1200