1991 XR600R Cylinder Head Compatibility Years??

Hi all,

I bought an XR600R that was abused pretty bad by a previous owner and decided to take it on as a project hoping for the best and of course going way over budget. I completely disassembled the bike and sent the motor to AMI in Puyallup for cylinder resleeve and a rod kit. They told me the head was about to go and I decided to risk it and put it together and hope to not have to spend any more money for at least 2 or 3 rides. Wrong.

The bike is dumping oil in to the chamber after startup and I'm sure I should just replace the un-rebuildable (according to AMI) head. Now, I found some parts on eBay and Craigslist, etc., but get mixed information over head compatibility. Some say '88 to late 90's fits my bike, but when I see closeup pictures of older heads they don't look different (like '86). Of course some bikes have black motors, while mine is unpainted aluminum, but other than that what's the difference?

Muchas Gracias.

Thanks for the reply to the two guys who did, but where did they go? I wanted to re-read them but they were gone.

Anyway, does anyone know about buying rebuilt heads or a good source for used XR motor parts?

Yes it seems my reply has been lost in cyber space!!

Let me know if you find a good source for 2nd hand XR600 parts!!

Heres, a repost of what I said yesterday!!.....

All the 600 and 650 RFVC heads are similar and are interchangeable to a large extent.

The cyl head dome sizes change (gives more or less compression), the decompressor systems changes (XRL/XL/XR stlyles) and the cam lobe spacing is often different. Hence its important to have a matching head and cam cover as the cams and lobes wont meet up!

The later XRL cam chain and sprocket is also different. For example, my XR650L (NX650) takes a wider camchain than the earlier lighter type on the XBR500.

The early XL/XR cranks are also a lot lighter than the later style as used on the XRL (The XL600 has wasted crank webs for example - revs much faster than a XRL!)

AFAIK, the valves and springs are all pretty much identical. The early heads tend to crack btwn the exhaust ports and the spark plug hole.....then the valve seats fall out ......ouch!

Lots of other changes in gearbox, selector direction and primary drive ratios as well of course.

Anyway, I hope this helps!

Some say '88 to late 90's fits my bike, but when I see closeup pictures of older heads they don't look different (like '86).

The intake ports are different on the older heads, as they were designed for two seperate carbs.

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