Four Valve Heads for the XV

I looked at four valve singles and saw the most promising to be the Raptor 700. I even went so far as to buy a couple of top ends. However, there was no getting around the fact that the cam chain was on the "wrong" side. It would have been cheaper and easier to fabricate heads out of billet aluminum. I sold it all at a steep loss. In the meantime, I could find no open class singles with their cam chains on the right. I'm still looking and welcome any leads.

I seek large bore (100mm+) heads (and possibly cylinders). Four valves and enough meat in the heads to separate the ports into their own intake (throttle body) flanges; and similarly the exhauts into their own headers. All this deployed ninety dergrees apart. This should maximize swirl and scavanging.

A few years later . . . . I think I have found a solution. Kawasaki's KLR650 single looks good: four valves, water-cooled. everything. The valve adjust is bucket-and-shim, a prescise method. Sadly, it's not shim-under, but perhaps we can change that without a lot of effort. Water-cooling looks like a bust at first, but these heads are accustom to wide bores and longish strokes. Perhaps water-cooling wouljn't be that difficult. And forget about seperating the ports. It was tried on some early four valve engines, but it was - in all cases - dropped. Why?

More to come . . .

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