Leatherat Posted March 16, 2011 Share Posted March 16, 2011 Don't you find it gauling that as motorcyclists we are being shafted by the manufacturers over the awful fuel economy of our bikes? My current steed is a 650cc twin, it weighs 215Kg and is capable of transporting 2 adults and a small amount of luggage. Fuel economy = 40-45mpg. My last bike was a XJ900S Diversion, 900cc transverse inline 4 cylinder which weighed 239Kg and is capable of transporting 2 adults and a small amount of luggage. Fuel economy = 45-50mpg. Whereas, my Ford Focus is a 1600cc transverse inline 4 cylinder which weighs 1200Kg, is capable of transporting 5 adults and a not inconsiderable amount of luggage. Fuel economy = 37-40mpg. (as a point of reference, the new BMW 1600cc bike is reportedly only getting 22-30mpg) How can a slip of a thing such as a bike, not be attaining fuel figures far in excess of those acheived by a heavy lump of a car? Motorcycle manufacturers have fallen so far behind their 4 wheel counterparts, that we as their customers really ought to be outraged at the dinosaur like machines we are being asked to accept. Surely the advancements of technology which make bikes go, and stop so well should be aimed at making them go a bit further on a gallon of 4 star? Link to comment Share on other sites More sharing options...
up.yours Posted March 16, 2011 Share Posted March 16, 2011 in a nutshell ,your focus doesn't preform like a bike. and iff you try making it,,, the fuel economy will fall. Link to comment Share on other sites More sharing options...
Leatherat Posted March 16, 2011 Author Share Posted March 16, 2011 in a nutshell ,your focus doesn't preform like a bike. and iff you try making it,,, the fuel economy will fall. Far too simple an answer, it doesn't work like that I'm afraid. The Ford's engine produces 113bhp and it weighs 1200kg, so the car has to haul 10.6kg per horse power The 650 twin produces 40bhp so has to haul 5.4kg per horse power The 900 Diversion produces 90bhp so has to haul 2.6kg per horse power So, the car is still far more efficient than either of the bikes. Link to comment Share on other sites More sharing options...
Ttaskmaster Posted March 16, 2011 Share Posted March 16, 2011 Your Dragstar (and I daresay the Divvy too) is carburetted, not fuel injected and is a very simple affair. By contrast, your Focus will have all manner of fancy (but too bulky for a bike) doo-dads to enhance economy without adding too much weight. This is the problem with older bikes. That said, I average 48mpg on my Drag. Honda's Deauville gets something like 67mpg. The highest mpg I've heard for a petrol bike is 87mpg on the Enfield 500 models. I think the Honda GC125 gets even more. Then you start getting into the economy of diesel... Link to comment Share on other sites More sharing options...
Leatherat Posted March 16, 2011 Author Share Posted March 16, 2011 According to an MCN review, the Honda Deauville averages 55mpg, it weighs 236Kg and has 65bhp on tap. Therefore it hauls 3.6kg per horse power. Meaning the car still out guns the bike. Even if you could squeeze 67mpg (nearly twice as much as the car) it would still mean the car pulls more weight per horse power and is therefore more efficient. These are quotes taken directly from a review of the Enfield Bullet in 2008........... 'The top speed of the Bullet 500 is an indicated 75mph, but the bike vibrates badly at this velocity and anything above 65mph is a tough strain on bike and rider'.......'The bike is so light, just 160kgs'.................So what we have here is a 25bhp antique road show, with added extras like an excellent, progressive front disc brake, a faultless electric starter, a smoother engine than you might expect and outstanding fuel economy. I logged 82 miles on my way home from Blockley in Gloucestershire, then stopped near Bridgnorth to fill the fuel tank to the brim again, with precisely £4.87p worth of unleaded'....... Having checked , the unleaded fuel average price for 2008 was £1.06 per litre, which means the 82 miles were covered using 1 gallon, very impressive, but as it states the Enfield puts out 25bhp and weighs 160kg which equates to 6.4kg per horse power, still less efficient than a family hatchback and I would venture, the Enfield is hardly a machine any of us would want to ride. Oh, and your quite correct about the 125's they're all up around 100mpg ish. My point is that car manufacturers have obviously invested time and money in R&D to make their vehicles more economic to run, whereas bike manufacturers seem to have spent their time making their machines go fast and look good. Maybe this is another reason that the motorcycle has gone from being the working mans cheap daily transport, to being a weekend plaything. Link to comment Share on other sites More sharing options...
MrLaister Posted March 16, 2011 Share Posted March 16, 2011 I'd venture saying that it's not just added electronics and other gizmo's which improves the cars economy, but the very way the engine is built and operates. I remember my old Nissan Micra mk1 (1990) got 65 mpg out of a 1 L engine without any additional electronics. Link to comment Share on other sites More sharing options...
Ttaskmaster Posted March 16, 2011 Share Posted March 16, 2011 That's a lot of dazzling maths, there... So what can be done to make bikes more economic, then? Bear in mind cars have a LOT more body and engine space to fit various devices that enhance the economy. An extra kilo or two of ultra-economic technology is pittance to a car, but half that junk just won't fit on a bike - Even the Tourers have to be huge to get decent fuel consumption and bike tech is still at the level of preferring chains over shaft-drives to save weight. The speed is not the primary concern in the design of most bikes. Especially in today's green world, economy and emissions are a bigger factor but minds even greater than ours have yet to solve this problem. If you do solve it, though, let us know!! Link to comment Share on other sites More sharing options...
Gas up - Let's Go! Posted March 16, 2011 Share Posted March 16, 2011 Oooooo This looks interesting.... According to an MCN review, Nope, now you've gone and quoted the noddy guide to motorcycling. Now where's the Jaffa Cakes and the Beano. PS - Your physics is flawed. You are looking at power to weight, but you are not considering the Kinetic energy you get from a 1000Kg car moving forward, this means you don't require as much effort from the engine to maintain constant movement. On a bike, you have much less kinetic energy and therefore the engine has to do more work. If you were to look at the fuel required to project a car from 0 to say 50 mph, and the same fuel required to propell a bike from 0-50, with the same rate of acceleration then you would find the bike is much more efficient. Once a cruising speed has been reached the car will use less fuel to maintain it's speed because it is less sucptable to influencing factors, and has the added energy generated from it's proppelled mass. Also, a car is a much more contained vessel, with smooth lines and lots of wind tunnel development. A bike is full of holes causing lots of wind turbulance and drag/resistance, not to mention the rider ! And another point, you quote figures for a car at optimum speed, whereas a bikes optimum speed is much more fluid. In that you will never get your 1000Kg Micra/fiesta/mini/whatever to get anything like 30mpg in stop/start city traffic, but a bike can opperate pretty close to optimum efficiency in the same traffic. Link to comment Share on other sites More sharing options...
Leatherat Posted March 16, 2011 Author Share Posted March 16, 2011 So what can be done to make bikes more economic, then? If you do solve it, though, let us know!! I've no idea, but I would have thought Mr Yamaha et al would have come up with somehing by now, and they probably would have if we as a collective stopped accepting the fact that bikes can't be made to do what cars obviously can. and as for the EFI vs carb, the Escort Mk1 is quoted at 27mpg, so that may have some merit. Link to comment Share on other sites More sharing options...
Leatherat Posted March 16, 2011 Author Share Posted March 16, 2011 PS - Your physics is flawed. You are looking at power to weight, but you are not considering the Kinetic energy you get from a 1000Kg car moving forward, this means you don't require as much effort from the engine to maintain constant movement. On a bike, you have much less kinetic energy and therefore the engine has to do more work. Good point, and one I'd not considered. Do you think that this would have a drastic effect on the mpg, the difference is quite large, or are there other things that might be done? Also, a car is a much more contained vessel, with smooth lines and lots of wind tunnel development. A bike is full of holes causing lots of wind turbulance and drag/resistance, not to mention the rider ! Not all cars, and not all bikes, there are some bikes that look almost egg like (CBRR1000) and some cars which are more akin to bricks (Ford Cortina?) And another point, you quote figures for a car at optimum speed, whereas a bikes optimum speed is much more fluid. In that you will never get your 1000Kg Micra/fiesta/mini/whatever to get anything like 30mpg in stop/start city traffic, but a bike can opperate pretty close to optimum efficiency in the same traffic. I don't see your point here, the figures are just figures, surely the type of riding /driving is irrelevent . Link to comment Share on other sites More sharing options...
oldtimer Posted March 16, 2011 Share Posted March 16, 2011 the reality is who gives a shit about all the physics and mpg,myself and my neighbour both left town at the same time today a journey of 6 miles i arrived home as usual 20 minutes before him on my bike not having to put up with the road works and traffic jams, i enjoyed my journey his face said it all when he got out of his car. Link to comment Share on other sites More sharing options...
Gas up - Let's Go! Posted March 16, 2011 Share Posted March 16, 2011 Not all cars, and not all bikes, there are some bikes that look almost egg like (CBRR1000) and some cars which are more akin to bricks (Ford Cortina?) It doesn't matter about the outline shape, the issue is the manner in which air would pass over/through this shape. Even a brick shaped Cortina whould have less air disruption than any bike. Despite it's shape a car has a smooth surface alowing the air to pass over it faily undisturbed. A bike will have holes for the air to get into, whether that is around the engine, riders legs, under the visor, around the arms and torso, the area around the wheels, under the muguard, around the pipes, the list is endless, but the fact remains that a bike is a mass of items that disrupts the flow of air and has massive drag. Look ath the race bikes, they cover them in farings to reduce the air drag, riders have state of the art smooth leather, speed humps, buckle-less boots all to improve the drag. Figures, it is important because overall, taking end-to-end economy the car has highs and lows, manufacturers will use whatever 'statistics' to improve these figures. Some cars ever kill the engine when stopped, because this improves the statistics they can quote nad even impacts the road fund licence value. Kinetic energy is hugely important, it has to be a constant, so if a car has a low drag coefficient, low rolling tyres and higher weight than a bike then there are less places for this energy to be dispelled, so the energy pushes the car further. On a bike this energy is dispelled by the ineffiecient tyres, high drag, noise etc. About the only place a bike has the advantage over a car in respect of energy loss is in turning. A car will loos energy to turnign forces, where in a bike the turning forces are so efficient we (the rider) has to force the bike to expel energy during the turn (counter steering), otherwise we'd turn to fast and lose controll. The kinetic energy isn't all that's important here, there are many other forces at play, but to put it in simple terms, an oil tanker travelling at 10 mph will take much longer to stop than a rowing boat......... Link to comment Share on other sites More sharing options...
Gas up - Let's Go! Posted March 16, 2011 Share Posted March 16, 2011 the reality is who gives a shit about all the physics and mpg, <snip> i enjoyed my journey his face said it all when he got out of his car. Totally agree. But for someone who askes the question why there is a difference, you need to have a basic understanding of the physics. .... and I've still got a Jaffa Cake left too Link to comment Share on other sites More sharing options...
Ttaskmaster Posted March 16, 2011 Share Posted March 16, 2011 A car will loos energy to turnign forces, where in a bike the turning forces are so efficient we (the rider) has to force the bike to expel energy during the turn (counter steering), otherwise we'd turn to fast and lose controll. I know sod all about physics, but... When I lean into a turn, say 20-45mph, I lose speed unless I apply throttle and power through. I sometimes use this on purpose to trim my speed a touch. Am I therefore losing energy to turning forces like a car does, then? Link to comment Share on other sites More sharing options...
oldtimer Posted March 16, 2011 Share Posted March 16, 2011 . .... and I've still got a Jaffa Cake left too oh god you have done it now darren mentioning jaffa cakes.we will end up with the 3 page thread on if its a cake or a buscuit. Link to comment Share on other sites More sharing options...
barkwindjammer Posted March 16, 2011 Share Posted March 16, 2011 Most factors are almost negligible, the common denominator between a car and a motorcycle is the internal combustion engine http://ffden-2.phys.uaf.edu/102spring2002_web_projects/z.yates/zach%27s%20web%20project%20folder/EICE%20-%20fun%20facts.htm Link to comment Share on other sites More sharing options...
Gas up - Let's Go! Posted March 16, 2011 Share Posted March 16, 2011 oh god you have done it now darren mentioning jaffa cakes.we will end up with the 3 page thread on if its a cake or a buscuit. I bleive that McVittes and the HMRC came to a conclusion on that....... It's a cake, cos a judge said so. A biscuit goes soft when stale, a cake goes hard when stale - so it's a cake. Link to comment Share on other sites More sharing options...
Leatherat Posted March 16, 2011 Author Share Posted March 16, 2011 Turning forces, bike vs car wind resistance etc is all irrelevent the original question was based around whether the bike engine is as efficient as the car engine, and it's quite clearly not. Link to comment Share on other sites More sharing options...
Gas up - Let's Go! Posted March 16, 2011 Share Posted March 16, 2011 When I lean into a turn, say 20-45mph, I lose speed unless I apply throttle and power through. I sometimes use this on purpose to trim my speed a touch. Am I therefore losing energy to turning forces like a car does, then? Yes, the art of turning uses energy, and therfore your speed will decrease, same as a car only as a rider we force the use of energy by turning 'out' of the turn with counter steer, whereas a car turns into a turn and requires force to keep the wheels from going forward. Two subtle but different uses of energy. My head is hurting now..... I thought I'd given up Physics when my daughter opted for Law & Chemistry rather than good old engineering topics! I do have a newsletter from our local IAM group that explains the turning forces though - if you are interested! Link to comment Share on other sites More sharing options...
sniff6 Posted March 16, 2011 Share Posted March 16, 2011 On the subject of fuel.....I found this about tips of the trade TIPS ON PUMPING GAS I don't know what you guys are paying for gasoline.... but here in California we are paying up to $3.75 to $4.10 per gallon. My line of work is in petroleum for about 31 years now, so here are some tricks to get more of your money's worth for every gallon: Here at the Kinder Morgan Pipeline where I work in San Jose, CA we deliver about 4 million gallons in a 24-hour period thru the pipeline.. One day is diesel the next day is jet fuel, and gasoline, regular and premium grades. We have 34-storage tanks here with a total capacity of 16,800,000 gallons. Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the gasoline, when it gets warmer gasoline expands, so buying in the afternoon or in the evening....your gallon is not exactly a gallon. In the petroleum business, the specific gravity and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products plays an important role. A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps. When you're filling up do not squeeze the trigger of the nozzle to a fast mode If you look you will see that the trigger has three (3) stages: low, middle, and high. You should be pumping on low mode, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you're getting less worth for your money. One of the most important tips is to fill up when your gas tank is HALF FULL. The reason for this is the more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every gallon is actually the exact amount. Another reminder, if there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up; most likely the gasoline is being stirred up as the gas is being delivered, and you might pick up some of the dirt that normally settles on the bottom. To have an impact, we need to reach literally millions of gas buyers. It's really simple to do. Link to comment Share on other sites More sharing options...
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