Redline was 9000, so they were right.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

Parts fiche available here as well as many other dealer websites:

http://www.freeholdhonda.com/fiche_section_detail.asp

Never heard of the CX500?  Then they have no credibility.  Funny how artists study and imitate the old masters before developing their own 'voice', yet young engineers seem delighted to reinvent the wheel rather than attend to groundbreaking historical designs, where the engineers had to rely on their imagination for development rather than fancy numerical modeling and CNC rapid prototyping . . . JMTCW.  Whether it was 9K or 10K, the design was/is notoriously robust and eventually supported turbocharging as well as scaling to 650ccs.

I don't mean to quibble, but all the mags of the era listed max hp (50) @ 9000rpm, and redline @ 10,000. www.bikez.com doesn't list a redline, but does list hp peak at 9000. It does appear that the turbo versions of this engine made max hp @ 8000rpm, so it's possible that they were redlined @ 9000rpm.
 I just can't find either a picture of the head without valve cover, or a cut-away drawing of the engine. The fiche pages show individual parts, but not a fully assembled valve train.

Fair enough on the red line thing, I just grabbed a number off the first reasonable looking site. As you probably know the method by which red lines are set is a tad arbitrary.

Anyway, why wouldn't you use a rocker at 10000 rpm? The inertia is a little higher than a direct acting cam, so you need higher spring rates, but on a design where you really don't want vertical height (width in this case) it makes sense to use a rocker.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.