What is the stock redline?

[VENMUS]

As the title says, I'm curious the stock redline of an XS650. (assuming all XS650's are created equal, if not, my particular model is an 81 Special)

I heard Sundie spun up to 9k (not intentional!) but I'm going to go out on a limb here and assume thats rather, er,... bad?

Also what's the limiting factor, if any individual wanted to increase said redline? (It's not me, I need the engine to last, but theoretically speaking). What if someone were to say they wanted max RPM's to be 10k, could the bottom end handle those speeds? Would the valves float at anything above 7-8 ish?

Just thinking aloud folks, feel free to discuss at leisure

Cheers,
Logan

 

[Sundie]

at 8, the values will start floating, and really, we're talking about a pressed crank 360 phased larger displacement twin, with no counterbalance on the crank. Above 7k, the forces are very large. Plus the cam is just not suited for that. Rephasing and welding the crank and getting a better high end cam and getting stronger valve springs might enable it, but it wouldn't last long. You'd almost certainly have to replace the stock points/tci. And it would idle like crap. You can't design a static cam that idles well *and* hauls at 10k.

Just my thoughts. I'm much happier re-gearing and increasing displacement slightly to get what i need out of it. I never want to see 9k again.