How much power do you need?

[Richard230]

When I first started riding on two-wheels, 5 hp was all that I could afford.  That got me up to about 50 mph and got me down the road. It just took awhile.  My first real motorcycle was a 1963 Yamaha YD3. It had about 10 hp at the rear wheel (18 PS claimed) and would hit 70 mph (while leaving a huge blue smoke cloud behind).  My 1964 Honda Super Hawk had maybe 25 hp and I got it up to 102 mph downhill one time before the valves floated. It went fast enough, but felt a little weak under a load and a bit strained on the freeway.  Ten years ago I bought a Yamaha FZ1, with 125 hp at the rear wheel.  That was way too much power for me.  I rarely use more than 1/4 throttle and have never had it anywhere near the redline. Pretty much a waste for my kind of riding. 

I have concluded that about 50 hp is just about right for my needs and any more than that just doesn't make a lot of sense, as paying more for a bigger engine, with greater energy consumption and more weight, seems kind of inefficient to me.  If you are not going to use it, why pay for it and put up with any compromises?  But then I just ride to get from here to there and pretty much stick to the posted speed limits.  However, I have found lots of torque, like you get from an electric motor, very useful as it offers a very wide power band and makes riding  easy and less stressful.  My feeling is that the latest electric motorcycle models, like the Empulse, have about the right amount of power for my needs.  Do we need more?

So how much power would you like to have - and are willing to pay for, both in money, weight and efficiency?

[frodus]

I am kind of the same way. I have an SV650 which is not too much, but it's overkill for what I need for my riding style. The 150cc bikes in my endorsement class were fine, maybe a little more scoot, but I'd be fine with it.

My big thing is, I need it to go highway speeds. I need to be able to move out of the way quickly and able to react to what I anticipate might happen.

[oml]

From my limited experience I can only say that 34hp arent enough (a restricted Yamaha FZ6 from my driving school) for me, both acceleration and top speed (I've managed to get 140 km/h / about 85 mph downhill with several kilometers to get to even that) bored after a short while.
I could live with that, but the rather slow acceleration from 100 km/h onwards was a real dealbreaker - its kinda neccesary for quick overtaking manoeuvres, one is even tempted to call it dangerous not being able accelerate quickly (for the same reason its dangerous not being able to decelerate quickly).
I have to admit though that I might have not tapped all the potential of the FZ6 - thinks like the powerband, downshifting to overtake and so on are things I didnt and dont want to spend concentration and thought on.
But overall I think 25kW really is the lower end.

About the upper end ... well 200hp+ supersportbikes really seem to be kind of overkill to me, and I seriously doubt most of its owners know how to handle that. Dont they have already stuff that compensates/prevents the rear wheel from slipping out of sheer power? Sounds kinda stupid to me to build a vehicle with more power than it can bring to the ground.

But maybe with more time and experience my thoughts might change, quite possibly about 180 degrees


edit: several typos. man, im tired.

[BrammoBrian]

Just need more than the guy behind you!...  200 HP seems to do it!

[Shinysideup]

Having just put on a thousand miles on the Empulse, I'd say 54 hp, with the broad torque band of electric power delivery, is just about perfect for me.

In first gear, I've had to squirt out of the way a couple of times and it works. At my age, I don't feel I can think fast enough, nor are my reflexes quick enough for anything beyond 100 hp. My R1200R at 109HP got plenty fast near the red line, enough to make city streets become suddenly very busy to assess.  But the instant torque of the Empulse is a) a ton more fun and b) safer to exit sticky situations in city traffic. If I were touring two-up with some luggage, then more HP would be useful, otherwise: expensive overkill. Kinda like a 6000 lb 300HP SUV to haul a soccer mom to the grocery store.

For a couple of years, I rode a home-made electric bicycle that would consume about 800 watts max. With gears, it would haul 400 lbs up a 30 degree incline. Slowly. I would routine haul 4 full grocery bags 12 miles home after work and hardly work up a sweat. It really changed my mind about how much power it takes to move a human body and accomplish something useful with a vehicle at the same time. I called it SUBTAD: Sport Utility Bike That Ate Detroit.

So for all around use: haul some groceries, overtake other vehicles at 70 mph on the freeway, have some fun in the twisties, get out of tight spots, the Empulse is about ideal for me. Or it would be if the side cases and top box would become available... Brian??

[00049 (AKA SopFu)]

I joke that I can turn faster laps on my SV than I can on my 1098. It's a lot easier to tape the throttle wide open and focus on turning than to have to worry about throttle modulation. I definitely prefer the power of the 1098 on Chicago's free-for-all interstates, though.

[ttxgpfan]

My '86 500 Interceptor (Honda V4) was 52hp and 25ft-lb of torque.  Being a V4 the torque curve was flat as a pancake so pulling from 3k rpm was never a problem for a beginner rider, but after a year, and being 6'2" and over 180lbs, I had out grown the bike.  I kept it after moving up to my '91 VFR750 (another Honda V4, and take a drink).  It was a blast to run ragged on public roads.  I really could ring it's neck and not be in too much danger and really work on riding skills.  However the VFR was much more satisfying in other ways.  Mostly I fit it a whole lot better and the chassis and suspension was much better.  When I got it it was 80-85hp and 45?ish ft-lb.  By the time I got done with it, it had may mods, mainly a rare and awesome full exhaust which I had the best shop in the area tune ($900 total maybe) and was getting 95.4hp and 50.5ft-lb on the dyno.  I also had over $1500 in suspension in it.  Other upgrades included SS brake lines and aftermarket brake and clutch master cylinders, and 'racing' clutch plates.  The reason I mention this is for some reason on most bikes these would make the bike harder to deal with on the street, but through either the beauty of a V4, the VFR, or some luck picking parts they all combined to make the bike easier, faster, and safer to ride with a passenger and luggage up the PCH going fast enough to make pick-up truck dive out of the way as we barreled through some time after going through Big Sur if I remember correctly.  More torque would have been nice, but I'm not sure I really needed much more horse power.  After getting the exhaust system and tuning running her to the redline in 3 was damned impressive, 4th was OMG, 5th well, I never had the cajones to run 5th gear all the way out on the street.  I have been of the opinion since early 2000s that liter bikes were pointless, and don't get me started on when Superbike racing went from 750s to 1000s.  But, that being said, you can get accustomed to new levels of power, and Brian's argument has it's merits.  Because electric motors are so torquie, and there's no real penalty in efficiency with a bigger motor, having a motor that makes power like the Empulse does where max power comes at redline means you have plenty for riding around town with the rest in reserve for track days.  Which I think is how most riders would defend their liter bikes.

[FrankH]

I think the 13kW of my Enertia Plus is sufficient for city use. The only thing it lacks is quick acceleration from a standstill. But as I understand, that has to do with the amout of current that the motor controller can deliver to the motor, not with torque or motor power (or lack thereof). Acceleration while already up to speed is ok, the max speed of 110 km/h (~70mph) is ok for a short expressway stretch. I'm not as confident sneaking in front of cars at traffic lights as I was with my old ICE bike because even though I can't make shifting or clutch mistakes, against some of the more sportive cars (BMW, Audi) the Plus is only just fast enough from the moment the light turns green.

[Richard230]

Here is a good one for you:  My son-in-law fabricated a mountain bike with a huge 3 kW hub motor in the front wheel.  He then installed a 36V NiMH battery pack, with batteries stuck all over the place, including in his saddlebags.  The bicycle would run up to 45 mph (it just wouldn't stop from that speed, or most other speeds for that matter), and it weighed well over 100 pounds.  He tried riding it to work, from Marin County to San Francisco, but the juice wouldn't quite get him the last uphill few miles home.  Then it was back to pedaling, then pushing, then sweating and finally swearing. 

So the big hub motor is gone, replaced by a little 300 watt unit and an Li-ion battery pack.  Now the bike weighs about 50 pounds and it is actually possible to move under LPA (Light Pedal Assistance - which is what was needed during the early days of internal combustion motorcycle development). So there is such a thing as too much power - especially if it is a "bodge".   

[BrammoBrian]

Yeah, I was kind of joking about 200hp... it's fine for the track, but totally insane on the street.  Keep in mind that my daily commuter is an original Enertia (over 10k miles now!), which seems to get me around town plenty quick.  That said, it does have some limitations and the average speeds in Ashland, OR are quite a bit lower than most other areas of the country.  I guess I feel like the Empulse meets my requirement for "enough" power for the street.  So... I'll agree with Richard that it's around 50 - 100 rear wheel hp for the street, depending on the way the power is delivered.  I swear you can drop our 100 hp Triumph Street Triple R on an aggressive ride with the Empulse... 

[Gavin]

I agree with the assessment that the Enertia Plus would be perfect for almost all city drivers...suburban too.

I LOVE IT in Albuquerque...and we have "streets" that are 50 mph here.

I even do short highway (65 mph) trips...but more HP and weight are needed for longer trips or rides on the 75 mph highways.

But I have found that every rider wants 5mph more....then they get that 5mph and they want another 5 mph....it's a sickness

But the Empulse will be more power than I ever need...and seats 2...which is the biggest reason I think I'm going Empulse over Plus....well that and all the KILLER reviews the bike is getting both here and from the magazines...

Gavin

[Vibetrippin]

I have an LS650 it runs at just under 40Hp. I find that to be enough for everything except cruising the hwy for hours on end. Even the superslap isn't too bad for a while but then I find that vibration and the fact that I'm nearly redlining the poor single gets tiring. I don't think I even want another 5-10 Hp, I want another gear so that I can bring my RPM down.
Around town and in twisties I don't care about the Hp, it's all about the torque, which my big single has plenty of. As long as I can keep lots of torque I'll be happy with limited Hp.

OML, remember that the FZ6 you were using was restricted. I've never ridden one but from what I've been told they have plenty of zip, even for more experienced riders.