If my calculations are correct the PWR on the Ninja 300 and CBR 500 are exactly the same, 0.10 HP/lb. The Ninja puts out 39 HP with a curb weight of 384 lbs while the CBR 500 makes 47 hp with a weight of 432 lbs (ABS model).
Both bikes get roughly the same fuel mileage so if you want a smaller bike with a little more power than our 250s the Ninja might be the way to go. Of course there's other factors such as build quality, reliability, cost, etc. that you have to take into account but based on power alone they're equal.
And that calculation of PWR is perfectly relevant...as long as the rider weighs nothing...literally. Darn physics!
Throwing my 200 lb body (in gear) onto a CBR gives a curb weight of 632 lbs, and I'm going to conservatively give it 50hp (although 54 looks more likely). That provides me with 12.64 lb/pony.
The N300 gives me a 14.97 lb/pony ratio (an 18.4% difference, by my calculations), and we haven't discussed torque yet, which looks to be a major difference between these engines.
I think your 180 weight is wrong, so your calculation is also going to be wrong. Wet weight is 195kg
so if you use your calculation with the new numbers
it's going to be 40 divided (195+90) x 1000
140.35KW per ton
I think Lewi was talking about tare weight + 90kgs rather than wet weight + 90. I'm guessing tare weight is all fluids but no fuel, which would make sense as the regs allow the + 90kgs to compensate for the weight of the rider and the weight of the fuel.
Either way, it qualifies and should be quick for a LAMSer. Probably not as quick as the KTM Duke 390 tho.
The Following 2 Users Say Thank You to Will 250 For This Useful Post:
Just wondering why you did it upside down? It usually easier to understand as power:weight ratio. Bigger numbers = better. Your way bigger number = worse .
Either way, its within 20-25% of the power:weight of the 650, which is perfectly in line with the cc difference.
Absolutely. It's right where it should be.
Concerning my calculations, I figured that people would be more comfortable trying to comprehend 7.87lbs/hp than 0.127hp/lb. 7.87lbs is something everyone can understand. I do agree that having larger numbers be a negative is a little confusing.