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RockandGrohl
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RockandGrohl
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| C1REX |
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C1REX
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 Posted: 10:11 - 27 May 2013  Post subject: |
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Most Japanese 125cc bikes should do over 100mpg if ridden gently.
Full throttle riding can make it worse than some of the most economical bigger bikes, however.
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| Teflon-Mike |
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Teflon-Mike
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| Posted: 11:37 - 27 May 2013 Post subject: |
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mpg is an expression of power used.
Book says your engine makes 13bhp... it doesn't... it merely might; at peak power rpm, with the throttle wide open. Everywhere else, it will be making less.
Power is rate of energy transfer.
Fuel is your energy in... so how fast you burn the stuff is a measure of power, and a pretty good indicator of how much of the possible 13bhp you have, is being utilised.
Less than 70 to the gallon... you are probably using a LOT of it!
So where does it go?
Well? Power is Work Done per unit Time. Work Done, is Force x Distance. So do a bit of algebra and you get:-
Power = (Force x Distance) / Time
Distance / Time = Speed.... so we can say
Power = Force x Speed.
What force we got?
Answer DRAG.
Drag is the resistance to motion, and fact you were curling up behind your fly-screen, ought to give truth to the suggestion that wind resistance gets higher the faster you go.
So, Drag = Some constant of aerodynamics, x Speed
And our sum now becomes:
Power Used = Constants of Drag x Speed Squared.
Want to save 'Power Used'?
SLOW THE FUCK DOWN!
Biggest influence on MPG. Halve your speed, you'll more than halve your fuel bill!
Next?
Well, every time you touch your brakes, you are dumping energy that while moving is 'Kinetic energy' into the air as heat, from rubbing brake pads on a brake rotor.
Brakes tent to be a lot more powerful as the engine, or more, in as much as they brakes will chuck away the energy the engine created to get you moving, a LOT more quickly... How long does it take you to accelerate to 60mph? How long to brake from 60mph?
Riding 'reactively' with lots of throttle action, lots of brake action and lots of gearchanges, doing a lot of work, trying to max out the bike.....
a) often wont actually make you any 'faster' point to point; though so much involvement & lots of sudden and dramatic forces, like a roller coaster are likely to make it feel like you are going a bit quick.
b) all them high forces and loadings are robbing you of preciouse kinetic energy, gained through burning petrol.
Back off... give your self room; relax, dont keep it pinned until the last second aproaching a roundabout or whatever, roll off early, coast up at the speed your going to go around that roundabout, scrub off the kinietic energy doing something useful.... keeping you moving, rather than warming the air. Take the smooth line through the roundabout, so you dont scrub more energy through violent loadings, then accelerate moderately out, tracking with the throttle, so as to only ever be a 'little' wider open than the engine needs to keep going, rather than wide open, chunking loads of unuseable acceleration enritchement into the engine when it cant make much use of it.
Dont tail-gate. Leave following room, so if traffic slows, you can slow into the gap, without sudden braking.
Look up the road, see whats likely to happen, predict it, and like not tail-gating, do everything smoothly and early, so you aren't slamming on brakes or cracking the throttle to respond to changes... you've already dealt with them.
You'll get from a to b faster
You'll get from a to be with less effort / fatigue
You'll get from a to b with less chance of a crash
You'll get from a to b on less petrol
PLUS you'll save tyres, brake pads, shock absorbers, chains, sprockets and general expensive wear and tear on the bike.
BACK OFF. Slow Down. Stop trying SO hard and its ALL win.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
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| Ribenapigeon |
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Ribenapigeon
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| Posted: 11:52 - 27 May 2013 Post subject: |
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| Az |
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Az
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Az
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| Posted: 13:57 - 27 May 2013 Post subject: |
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P.S. The cbf is great on fuel, i go from Birmingham to Cardiff and back (260mile trip) all A-roads and doing 65mph all the way and it only costs me £18 there and back, so maybe you should just buy a CBF125  |
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Az
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| Posted: 13:58 - 27 May 2013 Post subject: |
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P.S. The cbf is great on fuel, i go from Birmingham to Cardiff and back (260mile trip) all A-roads and doing 65mph all the way and it only costs me £18 there and back (90mpg), so maybe you should just buy a CBF125 |
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Ribenapigeon
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| Posted: 14:12 - 27 May 2013 Post subject: |
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i've heard that things like special air filters and exhaust can aslo cause your engine to run lean so increasing engine temps. Probably best leaving an engne standard as its not going to be worth getting the fuel injection remapped or carbs retuned on a 125. Just don't thrash it so much. You don't have to go hurling down the dual carriageway at 70 ya know |
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| RockandGrohl |
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RockandGrohl
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Ribenapigeon
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| Teflon-Mike |
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Teflon-Mike
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| Posted: 15:06 - 27 May 2013 Post subject: |
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| HondaAz wrote: | I highly doubt it'll make a huge difference but apparently K&N air filters improves MPG as it allows ur bike to use less fuel but more air. |
Think about this; MPG is a measure of how much fuel you burn. More fuel you burn, more emmissions you get, right? Generally, better MPG also means better Emmissions.
GIVEN all the EU bullshit to get vehicle emmissions down, and all the motor-manufacturers, spending huge sums of money trying to devise ever better fueling maps to beat emmissions legislation....
IF it was as simple as using a K&N filter.... do you not think that rather than waste gazzillions of yen on R&D Mr Honda et al would merely be buying K&N filters and fitting them as standard?
After-market filters come in a number of flavours.
1/ OE replacement air-box filters.
These can do two, perhaps three things;
a) increase the peak airflow capability of the inlet tract, having more flow area than the original, made down to a price filter.
However, as the OE filter will have been selected to flow sufficient air for the power the engine makes..... it probably wont do very much for either your ecconomy or performance.
b) can increase the 'life' of the filter. Made of perhaps cleanable foam instead of clagable card-board, or maybe made of paper with more pleats so that it doesn't clog as quickly, it increases the period between service intervals.
c) the possible third thing; having a greater area of filter pleat, or being a different material; the 'partial-clogged' flow rate is likely to change, so between service intervals you dont suffer quite SO much drop off in flow capability. However, as that clog rate will have been predicted when calculating service intervals, and the filter sized to flow sufficient air when partially clogged, this ought make very little difference to an other wise standard and well maintained engine.
2/ Pod Filters, or after-market accessory filters.
These replace the entire OE inlet tract beyond the carburettor mouth, and put in its place a simple, usually cone filter.
These rarely flow more air than OE air-box filters; and they frequently suffer from having a very much smaller air-flow area.. Ie that are actually often MORE 'restrictive' to air-flow than what they replace.
Look trick though.
Usual reason for fitting them is convenience, on a special where not using the original carburettors, or the original engine, or having made other mods to the bike that prevent using the OE Air-Correction box; and they offer some filtration, and a little flow correction, over running an open mouth carb, but the tight turn needed for air flor through the filter pleats and into the carb mouth often provides a significant flow constriction, and for ultimate flow, an open carb mouth, or better still, a tuned induction tube would flow better.
Only reason I know that K&N's can improve MPG is where on a hightly tuned engine, you get a phenomina known as 'vapour stand-off', and reverse shock-waves pulsing back through a carb sucking fuel up the jets as they pass and sending it backwards out the carb intake.... where the filter can catch it, and if tuned right, jetted lean so it gets sucked back in on the next induction pulse.
Meanwhile..... more air less fuel, effects the mixture. If it was as simple as changing the charge mixture ratio, and making it leaner in fuel, to get better MPG.... you could do it a lot more easily by winding in the mixture screw, or fitting smaller jets to restrict fuel flow..... but then... WHY did the carb get fitted with them jets in teh first place? Oh yes, the manufacturers are all in cahoots with the government & the oil companies and want you to 'waste' petrol, dont they?  The Stioc micture strength, the hours spent on the dyno finding the correct carburation for the engine, all the talk of tuning, and re-jetting so that an engine doesn't burn out its valves from running weak, or belch clouds of blue smoke and pull like a blamange, is just so much pedantry, and the fact that engines NEED the RIGHT mixture strength to make best power AND best ecconomy, is just a myth, innit?!?!?
In short! Fitting after market filters, fancy spark-plugs or fitting the mythical magic carb that the oil companies supressed, the inventor assassinated and burried with Kenedy, is a load of bolox!
BEST ecconomy comes, most often from a standard motorcycle, in good standard of maintenence, ridden for ecconomy... which doesn't HAVE to be 'more slowly'... just more progressively, and smoothly and not as aggresively,
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
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| Copycat73 |
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Copycat73
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Joined: 11 Jan 2013
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| Az |
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Az
World Chat Champion
Joined: 16 Apr 2013
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| Posted: 19:33 - 27 May 2013 Post subject: |
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| Teflon-Mike wrote: | | HondaAz wrote: | I highly doubt it'll make a huge difference but apparently K&N air filters improves MPG as it allows ur bike to use less fuel but more air. |
Think about this; MPG is a measure of how much fuel you burn. More fuel you burn, more emmissions you get, right? Generally, better MPG also means better Emmissions.
GIVEN all the EU bullshit to get vehicle emmissions down, and all the motor-manufacturers, spending huge sums of money trying to devise ever better fueling maps to beat emmissions legislation....
IF it was as simple as using a K&N filter.... do you not think that rather than waste gazzillions of yen on R&D Mr Honda et al would merely be buying K&N filters and fitting them as standard?
After-market filters come in a number of flavours.
1/ OE replacement air-box filters.
These can do two, perhaps three things;
a) increase the peak airflow capability of the inlet tract, having more flow area than the original, made down to a price filter.
However, as the OE filter will have been selected to flow sufficient air for the power the engine makes..... it probably wont do very much for either your ecconomy or performance.
b) can increase the 'life' of the filter. Made of perhaps cleanable foam instead of clagable card-board, or maybe made of paper with more pleats so that it doesn't clog as quickly, it increases the period between service intervals.
c) the possible third thing; having a greater area of filter pleat, or being a different material; the 'partial-clogged' flow rate is likely to change, so between service intervals you dont suffer quite SO much drop off in flow capability. However, as that clog rate will have been predicted when calculating service intervals, and the filter sized to flow sufficient air when partially clogged, this ought make very little difference to an other wise standard and well maintained engine.
2/ Pod Filters, or after-market accessory filters.
These replace the entire OE inlet tract beyond the carburettor mouth, and put in its place a simple, usually cone filter.
These rarely flow more air than OE air-box filters; and they frequently suffer from having a very much smaller air-flow area.. Ie that are actually often MORE 'restrictive' to air-flow than what they replace.
Look trick though.
Usual reason for fitting them is convenience, on a special where not using the original carburettors, or the original engine, or having made other mods to the bike that prevent using the OE Air-Correction box; and they offer some filtration, and a little flow correction, over running an open mouth carb, but the tight turn needed for air flor through the filter pleats and into the carb mouth often provides a significant flow constriction, and for ultimate flow, an open carb mouth, or better still, a tuned induction tube would flow better.
Only reason I know that K&N's can improve MPG is where on a hightly tuned engine, you get a phenomina known as 'vapour stand-off', and reverse shock-waves pulsing back through a carb sucking fuel up the jets as they pass and sending it backwards out the carb intake.... where the filter can catch it, and if tuned right, jetted lean so it gets sucked back in on the next induction pulse.
Meanwhile..... more air less fuel, effects the mixture. If it was as simple as changing the charge mixture ratio, and making it leaner in fuel, to get better MPG.... you could do it a lot more easily by winding in the mixture screw, or fitting smaller jets to restrict fuel flow..... but then... WHY did the carb get fitted with them jets in teh first place? Oh yes, the manufacturers are all in cahoots with the government & the oil companies and want you to 'waste' petrol, dont they? The Stioc micture strength, the hours spent on the dyno finding the correct carburation for the engine, all the talk of tuning, and re-jetting so that an engine doesn't burn out its valves from running weak, or belch clouds of blue smoke and pull like a blamange, is just so much pedantry, and the fact that engines NEED the RIGHT mixture strength to make best power AND best ecconomy, is just a myth, innit?!?!?
In short! Fitting after market filters, fancy spark-plugs or fitting the mythical magic carb that the oil companies supressed, the inventor assassinated and burried with Kenedy, is a load of bolox!
BEST ecconomy comes, most often from a standard motorcycle, in good standard of maintenence, ridden for ecconomy... which doesn't HAVE to be 'more slowly'... just more progressively, and smoothly and not as aggresively, |
Ermm... okay? lol  |
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| Az |
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Az
World Chat Champion
Joined: 16 Apr 2013
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| Posted: 19:33 - 27 May 2013 Post subject: |
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| Teflon-Mike wrote: | | HondaAz wrote: | I highly doubt it'll make a huge difference but apparently K&N air filters improves MPG as it allows ur bike to use less fuel but more air. |
Think about this; MPG is a measure of how much fuel you burn. More fuel you burn, more emmissions you get, right? Generally, better MPG also means better Emmissions.
GIVEN all the EU bullshit to get vehicle emmissions down, and all the motor-manufacturers, spending huge sums of money trying to devise ever better fueling maps to beat emmissions legislation....
IF it was as simple as using a K&N filter.... do you not think that rather than waste gazzillions of yen on R&D Mr Honda et al would merely be buying K&N filters and fitting them as standard?
After-market filters come in a number of flavours.
1/ OE replacement air-box filters.
These can do two, perhaps three things;
a) increase the peak airflow capability of the inlet tract, having more flow area than the original, made down to a price filter.
However, as the OE filter will have been selected to flow sufficient air for the power the engine makes..... it probably wont do very much for either your ecconomy or performance.
b) can increase the 'life' of the filter. Made of perhaps cleanable foam instead of clagable card-board, or maybe made of paper with more pleats so that it doesn't clog as quickly, it increases the period between service intervals.
c) the possible third thing; having a greater area of filter pleat, or being a different material; the 'partial-clogged' flow rate is likely to change, so between service intervals you dont suffer quite SO much drop off in flow capability. However, as that clog rate will have been predicted when calculating service intervals, and the filter sized to flow sufficient air when partially clogged, this ought make very little difference to an other wise standard and well maintained engine.
2/ Pod Filters, or after-market accessory filters.
These replace the entire OE inlet tract beyond the carburettor mouth, and put in its place a simple, usually cone filter.
These rarely flow more air than OE air-box filters; and they frequently suffer from having a very much smaller air-flow area.. Ie that are actually often MORE 'restrictive' to air-flow than what they replace.
Look trick though.
Usual reason for fitting them is convenience, on a special where not using the original carburettors, or the original engine, or having made other mods to the bike that prevent using the OE Air-Correction box; and they offer some filtration, and a little flow correction, over running an open mouth carb, but the tight turn needed for air flor through the filter pleats and into the carb mouth often provides a significant flow constriction, and for ultimate flow, an open carb mouth, or better still, a tuned induction tube would flow better.
Only reason I know that K&N's can improve MPG is where on a hightly tuned engine, you get a phenomina known as 'vapour stand-off', and reverse shock-waves pulsing back through a carb sucking fuel up the jets as they pass and sending it backwards out the carb intake.... where the filter can catch it, and if tuned right, jetted lean so it gets sucked back in on the next induction pulse.
Meanwhile..... more air less fuel, effects the mixture. If it was as simple as changing the charge mixture ratio, and making it leaner in fuel, to get better MPG.... you could do it a lot more easily by winding in the mixture screw, or fitting smaller jets to restrict fuel flow..... but then... WHY did the carb get fitted with them jets in teh first place? Oh yes, the manufacturers are all in cahoots with the government & the oil companies and want you to 'waste' petrol, dont they? The Stioc micture strength, the hours spent on the dyno finding the correct carburation for the engine, all the talk of tuning, and re-jetting so that an engine doesn't burn out its valves from running weak, or belch clouds of blue smoke and pull like a blamange, is just so much pedantry, and the fact that engines NEED the RIGHT mixture strength to make best power AND best ecconomy, is just a myth, innit?!?!?
In short! Fitting after market filters, fancy spark-plugs or fitting the mythical magic carb that the oil companies supressed, the inventor assassinated and burried with Kenedy, is a load of bolox!
BEST ecconomy comes, most often from a standard motorcycle, in good standard of maintenence, ridden for ecconomy... which doesn't HAVE to be 'more slowly'... just more progressively, and smoothly and not as aggresively, |
Ermm... okay? lol |
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| Rogerborg |
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Rogerborg
nimbA
Joined: 26 Oct 2010
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| Posted: 20:47 - 27 May 2013 Post subject: |
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My experience of bikes from 125 to 500cc is that fuel economy is largely a function of speed.
If you ride at a (real) 65mph then you'll get ~70mpg. If you want to get better economy, roll off the throttle, there's no magic wand that you can wave to get better economy at higher speed.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike |
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Old Thread Alert!
The last post was made 12 years, 23 days ago. Instead of replying here, would creating a new thread be more useful? |
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