TOPIC:

Me motor wants to explore the 8.5K-11K RED zone on my tachometer.
Feels like she can handle it, but I don't necessarily think it would be a good thing to do regularly. 
Not sure what to set me rev limiter at either...

I seem to remember reading that roller bearing cranks aren't happy too far north of 9k ??

Roller cranks are good to 11k which is the point where the rollers start to skid so set the limiter just below that.
I exceed 9k regularly but have seen 12k on mine a couple of times 

If running stock valve springs, they might be your limiting factor.  High tension springs will tolerate a higher redline, but they also create a higher seat pressure, which can increase valve recession.

Running it to 11,000 rpm increases the stress on reciprocating parts 66% over the 8500 rpm number.
Reciprocating mass stress is not proportional with rpm...it's squared.
Increase rpm 29%  Stress goes up 66%.

If it were built with higher rpm in mind, then go for it.
If not, then you can build it to that standard after you find the limit.

OK, I'll get technical for some trivia.   You are probably expecting an smart computer setting rev limiter, but in this case is all about dimensions.

Engineers don't care more for RPMs, because they know everything that rotates is doing it either, on metal roller/ball bearings, or plain bearings (hi press film of oil), so on paper, a properly lubricated engine is almost frictionless.  

...............but they do worry about things that reciprocate, like cylinders and valves. ......  Thus over the years it has been established that safe limit for internal combustion engines is an average piston speed of 3500 ft/min.     Although this is arbitrary,.........some manufacturers may even allow 4000 ft/min

So assuming 3500 ft/min safe limit, this formula is what set the red line tachometers on vehicles with reciprocating internal combustion engine.

RPM = 6xPS/Stroke

PS is average piston speed in ft/minutes, and stroke is in inches (Yes, am using archaic US system of measures).
   
..so depending on the stroke of the engine, limiting piston speed to 3500 ft/min....following the formula; red lines would be like this.

For a KZ900 with a 66 mm (2.5 inches) stroke..........red line would be 8400 rpm

For a KZ650 or KZ750, with 54 mm (2.12 Inches) stroke....red line would 9900 rpm

For my Honda Fit automobile with a 1500 cc engine and whopping stroke of 89.4 mm (3.5 inches)....red line is 6000 rpm (tach actually says is 6500, indicating Honda's confidence)

Note; The Honda Fit is actually moving its pistons up and down faster at 60 mph and 3000 rpm, than a KZ750 at same speed and 4500 rpm.   Just to make the point. 

Sorry, I just had to get technical......and no,.......... I don't intend to find out if red line is safe on any vehicle.   

Interesting info Hugo.  Thanks!

Kawasaki had a 9,000 rpm redline with the Z1900/KZ900 engines and the 1977 KZ1000 engine.  In 1978 they lowered the redline to 8500.

I have a hard time distinguishing a 77 from a 78 KZ1000 and I use the tach to tell which is which.  Last summer at a bike show a guy I know had restored a 78 but was unaware of the different redline and had used a 77 tach.  I mistook it for a 77 because of the tach.

As Hugo mentioned, the formula he posted will calculate the average speed of a piston, which will be significantly different from the actual maximum speed. At either end of the stroke, piston speed slows dramatically and then essentially stops for a very short moment. As the piston changes direction, there is a rather violent acceleration, the rate of which slows as the piston reaches mid-stroke. The slowing rate is the result of the arc of the big end of the rod as the crank throw reaches 90 degrees in relation to the crankshaft centerline (when the rod journal center is horizontally aligned with the crankshaft center).  From that point onward, the rate of acceleration increases until near the end of the stroke. 
This gets even more complicated in an offset engine, like the ZX10, where the cylinders are actually located slightly forward of the crankshaft.
At any rate, I am sure that the formula Hugo posted works brilliantly for street oriented engines.

You also don't want to exceed 38 degrees of total advance on these engines especially on a street ridden bike (I saw the picture of that Dyna box) 36 degrees is safer and you won't feel much of a difference.

You can go to 40 degrees but that is mainly for drag race engines which run for short duration (printed on the Dyna rotor)

Set RPM limiter at 9500 for a street motor, shift at 9000 (higher OK for a drag engine)
It has already been pointed out that safe maximum piston speeds need to be taken into consideration.

If you want to flog your equipment it needs to be built up beyond stock levels to be able to take the abuse.
 

Speaking of Honda, the F20C engine had a 3.31 inch (84mm) stroke and a redline of 9000. This is the engine used in the first generation S2000 sports car.

As long as I am running off into the tall weeds, shifting at the redline is not always the quickest way down the street. As I understand it, for maximum acceleration, a rider should shift to the next gear when that gear will produce the same torque as the current gear. This can be plotted on a dyno run by doing a full pull in each gear and noting at what rpm each pair of curves intersect. Conversely, a single pull can be used, and then the torque values can be calculated using each gear ratio. Seems like I may have a calculator buried away somewhere in a dark corner of my computer. I once put in the info for the Concours I rode in those days, and was surprised that the best shift points varied by several hundred rpm.

I've found going over 8-9000 RPM doesn't buy much in fact I've lost a second or two in a high speed pass. 
Steve