Kawasaki Z900RS

[Ulvetanna_imp]

Ok first off rideapart was wrong because there was no 15 DLX and there are likely no more than 300 14 dlxs (the only year it was made) in North America

The CB has been dynoed by many magazines and many members here so 85 rwhp is a figure I feel confident using (NOT at the crank).

http://www.motorcycle-usa.com/photo-gall...cond-ride/

I have not seen a dyno on a 900RS yet, but if the std 125 hp Z900 loses 12 hp on the dyno to the rear wheel and comes out at 113, that's what I am going to figure on (ie: a 12 hp loss). Surely the detuned RS isn't going to rate only 2 hp less. Using someone else's actual dyno charts is the only measure we can use isn't it? Can't trust the manufacturers to tell us the truth since they don't compare apples to apples. (rwhp vs crank hp for example.. dry weight, vs curb weight vs wet weight for another example) so we rely on magazines to weigh and dyno and quarter mile them for us and compare those figures.

https://www.google.com/search?q=dyno+cha...qukDl-zsM:

I used the 545 pounds weight from from the standard 13 and 14 models (yes the dlx is 30 pounds heavier but like I said, it was a one off model and there aren't enough of them in the country to use as a fair comparison)

I don't care what numbers you use, the Kaw is lighter and has more hp, but the difference is not as large as some would make it out to be. But in the REAL world, where we actually ride the motorcycles daily, FEW of us (at least few of us on this board from what I have read) are going to notice the difference in HP between the two (except maybe on rare occasions). If the CB's dyno chart shows more horsepower in the rpms I ride in and the RS's dyno shows a hp advantage only in the upper regions of the tach near the red zone where I don't ride, then the CB will actually be the more powerful bike in my hands. And even if the Kaw shows a couple hp advantage in that 3500-5000 rpm range, that really doesn't mean squat does it? That is exactly the situation I was in with my Gen 1 FZ-1 I was riding when the CB came out. The CB made more hp than the FZ in the 3500-5000 rpm zone I ride, but once the FZ hit 8000 rpms. there was a steep rise in HP up to the 13,000 rpm redline where it smoked the CB... but I never rode it there. For me, the CB was the more powerful bike.

Some guys (you maybe) like to ride around banging them off the rev limiter, but I would say generally speaking those that would buy this type of bike are of a certain demographic that got that out of their system many years ago.

If it isn't about the power, then why has it become about the power? If a guy wants power, get something besides a CB1100. If a guy likes the CB1100, buy one. I sure did. Who in the world ever said different?

"but that extra 25 HP and 80-pound weight difference"

more like 15 hp (stock CB dynos about 85 rwhp the new RS will dyno about 99 rwhp... the full bore Z900 only dynos 113 rwhp or 28 hp more than the CB)

the weight difference is 70 pounds (CB 545 lbs... RS 475 lbs)

Ok, for you guys with far more experience than me, how much can you actually feel that difference in power?

I mean my HD dynoed at 86 rwhp and 92ft/lbs tq, my Buell is listed at 103hp, 84ft/lbs tq (at the crank I suppose) and whatever the CB is and I'll be honest - I can't really tell that much of difference between them.

One thing to keep in mind is that the Z900R, and even the RS, are much quicker-revving engines than the CB1100's. The CB has a 9.5:1 compression ratio. The Z900RS has a 10.8:1 figure, much higher. The Z900R has an 11.8:1 compression ratio.

If you consider those values, along with far less rotating mass in the engine, and far less mass to accelerate, you can imagine that the Kawasaki is going to get with it pretty well.

In the link I posted to motorcycle.com's article by John Burns, he mentions that for all practical purposes, the RS accelerates about as hard as the R model because the torque curve is shifted downward about 1000 RPM, and the RS is geared lower as well. Of course the R will pull away above 9K RPM due to its 13 additional horsepower but for most riding you'll never be up there. Well, except for me and those other hooligans who haven't gotten it out of our systems, lol.

So heck yeah, you can feel it, big time.

Anyway, on any dyno or any scale, crankshaft or rwhp, avoirdupois or metric, abacus or computer, the CB1100 is a lot heavier bike with considerably less power than the Z900R/RS.

Spec sheets help sell bikes, no doubt about it.

Of course it's a shame we aren't talking more about the awesome CB1100RS which Honda did not bring the United States. But it's better than talking about the weather.
I just also wanted to mention that the SAE horsepower figures reported by the manufacturer to the government on a document called a "Manufacturer's Certificate of Origin."

The methods used to measure crankshaft horsepower are, and must be, standardized to meed federal regulations. They can't really be all over the map like one dyno to the next.

Everything has to be measured under controlled conditions and corrected for pressure, temperature, and relative humidity, for example.

We are going to see much more variation from one rear wheel dyno to the next.

If one was to knock off about 10 percent, it'd be pretty close.