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xr200 heads

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Any difference between 83 and earlier head vs. 86 and later cylinder head..

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Yes.

There are two different widths for the cylinder head mount, 36 & 42 mm.

There are a wide variety of casting numbers.

Some slightly different fins.

All same size valves.

Minor porting difference depending on casting number, may be just foundry tolerance.

 

IMO for trail bike use the only issue is the width of the head mount to suit your chassis/mounts.

http://www.thumpertalk.com/topic/1003781-2002-xr200r-which-top-ends-will-interchange/?p=10535473

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OK didn't know if one flowed better then the other...thanx

There are flow differences but as I said probably more to do with foundry tolerances than by design.   If you want high flow you will need porting. Teamrude is a better source of info on heads than me.

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I read in one of the postings here don't know which one bout powroll stroker engine (yada yada)..bout using a newer style head vs. A ported earlier head..so that to me says newer head better...maybe I read it wrong...yes my meo2 engine in 87 frame upper mount works but not perfect offset..will early style mount work correctly or the pre 84 frame upper mount offset is not correct in 87 frame regardless

Edited by 75nova420

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The info I have is more involved than just differences between years, with some early heads being the best depending on intended rework.   For trail use, or a near stock engine, I don't think your, or my, butt dynos could tell the differences, so for trail riding just match the ports. I have several two valve heads from a variety of years/models and my selection criteria is on  the width of the cylinder head mount to suit the intended chassis.

 

As I said in my previous post the best info will be form those who build race engines and have flow bench info on the two valve heads.

 

I don't know about the head mount issue vs mount plates but I think most mount plates are strait.  What little research I did indicated that most of the early XR185/200/ATC heads have a 42mm wide boss, the other width is 36mm.

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OK any idea why ours heads have extra threaded holes for what appears to b a different intake option

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Basically heads are so close to each other as far as power it makes no difference. Also certain models of atc/trx/XR/XL use different intake manifolds, no biggie.  I believe most have both sets drilled and tapped but i will look at my pile of heads in shop.  

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