The 750 Nighthawk vs sport bike (600)

[Option13]

No way. A bike with a 13,000 RPM is going to burn up oil and gas faster than a bike with 8,500 RPM.

Do you have any actual figures or are you just insisting on things you aren't sure of?

Oil consumption is a function of build quality. RPM is a function of engine design. So where are you getting these concrete, always correct "facts"?

[Laminar]

I spent 4 seconds Googling "GSXR 600 mpg." It wasn't hard.

[flynrider]

No way. A bike with a 13,000 RPM is going to burn up oil and gas faster than a bike with 8,500 RPM.

  Where did you get the idea that rpm has anything to do with mpg?  It has very little bearing on it.  Fuel burn is a function of the amount of horsepower you're generating.  What rpm you use to generate that hp makes very little difference. 

  Your argument might make more sense if comparing the two bikes running wide open throttle continuously, but who rides like that? 

[TimmyJ]

When you turn extreme RPM's, your spark plugs are firing faster, thus more fuel is being used. Those higher RPM's also mean that the oil is being broken down faster because of the friction/heat generated by the increased revolutions per minute. Basic engine 101.

Imagine going 2,000 RPM's for a mile, and then imagine going 7,000 RPM's for a mile. Which ride will burn up the most gas and oil? Of course if the rider of the sportbike shifts at 8,500 instead of 11,000 or 13,000, then yes he would get the same oil and gas milage as an NH. But how many sportbike riders will not redline and purposley shift at the lower RPM's all of the time? Not many.

Let me add that running at high RPM's adds tremendous wear to the engine, I dont care how well it is engineered. Here is a Suzuki GSXR 1,000 which redlines at 12,000. Note how the rider at the beggining not only redlines between shifts, but at one point keeps it at 12,000 while weaving between cars. That has to put major stress on an engine. Im not saying everyone rides like that. What I am saying is that even hitting redline sometimes will cause more usage of oil and gas compared to a lower redline vehicle.

[Laminar]

Welp, I'm done here.

[muttstang]

Sorry Timmy but you are still incorrect.  an engine designed to turn at a higher rpm doesn't mean that it will burn more fuel.  Fuel usage is more a function of vehicle/rider weight, drag coefficient, and engine efficiency.

I've had vehicles that would get better mpg's at 80 mph then at 55 because they were operating in a more efficient rpm range (which was higher).  You can use more gas when you bog the engine with low rpms then when you operate in the proper rpm range for an engine.

Just because some people ride like idiots doesn't mean that the machines that they are riding inherently get worse gas mileage.

[Option13]

Until you have data, your assertions are just hearsay.

That video could be replaced by any generic sportbike video. It shows nothing other than someone's idiocy.





Annnd I'm out.

[TimmyJ]

Oh, so the rider above has the same gas milage riding 55 MPH at 10,000 RPM's, as opposed to riding 55 MPH at 5,000 RPM's?

[muttstang]

you are talking about some specific rider that is riding like a moron.  That does not apply to someone who would ride sensibly and is considering getting a sport bike instead of a CB750.

And actually, the difference in gas mileage would not be as much as you think between 55 mph at 10k rpm vs 55 5k rpm.  Each revolution at 10k rpm would require about half as much fuel as the same revolution at 5k rpm because the same forces are acting on the motorcycle (weight of the rider/bike, rolling resistance, and wind resistance)

either way, the comparison doesn't really apply to anything useful

[TimmyJ]

I think it does. I was challenged earlier in the thread when I stated that higher RPM bikes will use more gas and oil. Hell, basic  physics is on my side with that. Im not saying it is huge, Im saying there is a difference.

Can less weight help make up for that? Of course, but that is a different subject.

[muttstang]

modern engines barely consume oil unless there is something mechanically wrong with them.  a 10 year old bike will likely consume much more oil then a bike that is only a couple of years old.  And that comparison is valid because the 750 is no longer offered from honda but there are plenty of 600cc sport bikes out there that are new and cheap to purchase. 

for mpg, look at the specs, it's not hard to do a google search.  the cruising rpm on a sport bike is not 10k rpm unless the rider is an idiot.  Therefor, your argument is invalid for any sensible rider.

[muttstang]

anyway, that's enough re-stating the obvious, I'm out

and as a mechanical engineer with both a Bachelor's and a Master's of science in this sort of thing, I do think I have a solid grasp of the physics behind it.

[ariwhiteboy]

If a bike is "using oil" then you have problems beyond what this thread is covering...

3000 miles is 3000 miles is 3000 miles...

[TimmyJ]

The 4,000 extra RPM's of a sportbike generate much more friction and heat since the moving parts are moving 4,000 revolutions per minute faster. But what all of you are saying is the engine gets away with it scott free? Oil doesnt break down a bit faster? No cause and effect? Oh ok.

Mabye the apple fell sidways and Newton was wrong then.

[muttstang]

friction has no speed component in it's calculation.

maybe you are refering to the wrong Newton.

[TimmyJ]

I was referring to Newton...the the guy they named the fig newton after.  

To put it simply, more friction = more oil breakdown

Am I wrong? Now, if the sportbike is using a thicker oil that doesnt break down as fast and handles extreme RPM's, ok then, now we are talkin' something different. The whole point of this thread was me trying to figure out if I really want a sportbike this next spring to go along with my NH. I was going to keep the NH as well, and use it for trips.

I wrote this thread because I had looked at a video review of the Honda CBR 600 RR (which gets 15,000 RPM), and the reviewer said the tires last about only 5,000 miles, and the gas mialage was only 25 MPG, etc etc. So I wrote this thread to point out how a sportbike isnt all roses (other than the riding position) and asked if I really wanted the maintenence hassles. But all of you are saying that there are no real differences in mialage, tires, oil, etc. So if I can find that review video again, I'll post it.

[twoone60]

friction has no speed component in it's calculation.

Friction might not but if your significant other is slowly rubbing your arm verses some one giving you what we used to call " Indian burn "  We can see that heat generation does.


 

[TimmyJ]

Thank You twoone60, a good way to put it!

[twoone60]

reviewer said the tires last about only 5,000 miles, and the gas mileage was only 25 MPG
  Tires come in many  different compounds, from a soft sticky compound for grip to a hard compound for longevity.   Tire wear is also a function of riding style.  I would think the sport bike tire would be the soft sticky tire.  Even if you road it like your nighthawk it would were out faster.

   Fuel mileage is a function of engine efficiency and power required.  I would think that the efficiency of both engines IE Horsepower per gallon is close.  The sport bike might actually get more horsepower per gallon.  
   If you ride the sport bike the same as the nighthawk you should get the same or better . But wheres the fun in that
Here are the specs. for a new CBR600RR Honda estimates 40 mpg        
2012 Honda CBR600RR Specifications
9/23/2011 3:00:00 PM
Model:    CBR600RR / CBR600RR C-ABS
Engine Type:    599cc liquid-cooled inline four-cylinder
Bore and Stroke:    67mm x 42.5mm
Compression ratio:    12.2:1

Valve Train:
   

DOHC; four valves per cylinder

Induction:
   Dual Stage Fuel Injection (DSFI) with 40mm throttle bodies, Denso 12-hole injectors
Ignition:    Computer-controlled digital transistorized with 3-D mapping
Transmission:    Close-ratio six-speed
Final Drive:    #525 O-ring chain
Suspension    Front: 41mm inverted HMAS cartridge fork with spring preload, rebound and compression damping adjustability; 4.3 inches travel
Rear: Unit Pro-Link HMAS single shock with spring preload, rebound and compression damping adjustability; 5.1 inches travel
Brakes    Front: Dual radial-mounted four-piston calipers with 310mm discs
Rear: Single 220mm disc;
Optional Honda Combined ABS (CBR600RR C-ABS)
Tires    Front: 120/70ZR-17 radial
Rear: 180/55ZR-17 radial
Wheelbase:    53.9 inches

Rake:
   23.5°
Trail:    97.7mm (3.9 inches)
Seat Height:    32.3 inches
Fuel Capacity:    4.8 gallons, including 0.9-gallon reserve
Estimated Fuel Economy:    40 mpg
Colors:    CBR600RR: Red, Black
CBR600RR C-ABS: Black
Curb Weight*:    410 pounds (CBR600RR) / 434 pounds (CBR600RR C-ABS)

*Includes all standard equipment, required fluids and full tank of fuel—ready to ride.

Honda's fuel economy estimates are based on EPA exhaust emission measurement test procedures and are intended for comparison purposes only. Your actual mileage will vary depending on how you ride, how you maintain your vehicle, weather, road conditions, tire pressure, installation of accessories, cargo, rider and passenger weight, and other factors.

Meets current EPA standards.

Models sold in California meet current CARB standardsand may differ slightly due to emissions equipment.

©2011 American Honda Motor Co., Inc. • All Rights Reserved

Specifications subject to change.
 

[twoone60]

I just read the title of the video.  Power required to do a 170 mph is a whole lot more than 70 mph hence a lot more fuel consumed per mile. 
  The brains required to do 170 mph safely on public roads that my mom,dad and little nieces and nephews ride on have not been invented!

[muttstang]

friction has no speed component in it's calculation.

Friction might not but if your significant other is slowly rubbing your arm verses some one giving you what we used to call " Indian burn "  We can see that heat generation does.


 

in which case the oil is passing through the system more quickly and disipating heat more quickly as well.  The amount of time that you are running those RPM's is a very small percentage of the overall duty cycle unless you are an idiot or you are doing a track day.  Unless you are running at sustained high rpms, then your oil consumption won't be an issue. 

besides that, rpms is a minimal player in the whole thing.  you also are dealing with tighter engine tolerances.

but beyond all of that, your premise is still flawed.  You don't compare the 2 types of bikes for gas mileage and oil consumption unless they are going to be ridden the same way.  If you are riding the sport bike at much higher rpms then the nighthawk, then your comparison falls apart.

look at a corvette.  they get 30+ miles per gallon but put down 400+ horsepower.  Weight and drag are your biggest players in the fuel efficiency game.  A 6000 lb truck gets only 15-20 mpg because it is heavy and has the aerodynamics of a brick.  Not because of it's bigger motor

[AmericanClassic]

[twoone60]

You don't compare the 2 types of bikes for gas mileage and oil consumption unless they are going to be ridden the same way

This is 100% correct also add in tire wear.


  The Corvette Is capable of 400 horsepower and 30+ mpg but not at the same time.

[TimmyJ]

Excatly what I am saying. A rider may not push his bike all of the time, but he will push it SOME of the time. And when he pushes it, the sportbike will be under more stress, which would translates into less milage and harder engine wear. And tire wear.

[Option13]

Ugh.



So what's your point? Ride them the same way and there's no difference. You're changing two variables at the same time - the way the bike is ridden and the bike itself. Therefore your comparison is meaningless.