[rohitoasis]

Allow me to start with a disclaimer. I do not claim to an expert. What i have penned down below is a series of observations i have done over a period of last year or so. This might be true only to my bike, its current condition or my riding style. There are points where i do not have any logic or explanation to the behaviour. I thought i would minute these observations down.

With the recent prices that we see in the petrol, I am assuming all of us would be feeling the pinch. i thought we would use this thread as sounding board on what we are doing wrong and what we could do better to get better fuel efficiency from our vehicles.

My bike is nearly 9 years old. But for the first 7 years of my life, i had never bothered to check and document the costs associated with the ownership. I used to stay 2 Km away from office and had to fill petrol once in a month. I used to service the bike once in 3 months irrespective of the mileage done. I covered around 21K km in this period of 7 years. With 6 day working, it was used basically for this 2+2 km commute.

In June 2019, i got transferred to Coimbatore which is around 50 Km away from my hometown Palakkad. I was amused at the thought of an extended commute. By a fortune or misfortune, the rubber switches in the instrument cluster gave way on the last week of my stay in Chennai. So i had a new speedometer console installed and with the odometer reset, i was able to document this second phase of motorcycling fairly decently. There was a steep learning curve on fuel management and service intervals from this day onward. I am now nearing 20K Km of this second phase of life. These observations are not done in the most scientific manner and i do not claim to have technical expertise to claim if they are actually valid observations or some kind of placebo effect. I could have used any of the readily available apps. But I started the job or recording my fuel consumption as a task to keep my nephew busy and have a routine to follow rather than spend time on mobile gaming and created and keep this excel sheet updated. At least some time learnt to use excel and its formulae could be an essential life skill for future.

ktm duke petrol.xlsx

Why i fancied this new phase of my motorcycle ride.

This is the view from my house.



Few of you may recognise this bit of NH544.

We purchased this house almost 30 years back just because of the view of highway and my attraction towards automobiles. Through the years, i would watch a lot of cars and in recent decades; tonnes of bikers in this piece of road and secretly wish on long rides. With a 6 day work week, it is not the most practical option to go on rides in the weekend and it excited me to have weekday commutes of decent length. (That and me being an introvert, i rarely enjoy large groups and group rides). When you combine these with the bike that i own. Duke 200 is one of those bikes with just enough power not to overpower its chassis. It has a super stiff chassis and amazing cycle parts for the money it charges. You think of executing a maneuver and the bike just responds the exact same way you wished it for. Makes it fun even at 3/10th or 4/10th of its massive capability. Yes the rides give me sore bum, but the joy you get in riding this easily exceeds any inconvenience. With such roads and a mighty steed at my disposal, these commutes become the bright spot of my daily routine.

How i combatted boredom in these rides.

For the first few weeks of this commute, i would set up benchmarks for me. To reach a landmark within a set time or complete the journey in set time or have an average speed of XX. These rides were fun for some time.

From a time when i chased average speeds. (Notice the sticker of the new speedo unit)


Soon i realised the impracticality having time or speed based targets. With 5 traffic signals in the 22 Km from Kerala Border to my house, multiple speed cameras and occasional random police checks, i understood it was not safe to target average speeds anymore. With this realization i decided to maintain the rides to never exceed the speed limit. So i would do around 70 kmph (10 kmph lower than the speed limit to avoid any fines due to speedo error).

When you reduce speed there is a whole new world awaiting you:

- You start noticing details that eluded your vision originally. You see the beautiful morning sun rise (My morning commute starts at 0645 Hrs) and evening sunset (Commute back is at 1740 Hrs). (Though this started to blind me and i had to get the dark visor for the helmet. Was not available in the Chennai showroom, so had it brought from Revzilla and brought to India by a colleague)
- You are gifted with longer reaction times to any obstacles on the road.
- You have time to review your braking distances and time required to accelerate to speed. (Helps you target and hone into gaps in traffic)
- You learn better throttle modulation.
- Gifts you the Zen like ability not to get coaxed into races with teenagers.

- And finally grants you extra range on the limited fuel that can be filled in your bike.

This was probably the first time i realised i could achieve substantial range from the tiny tank of fuel.


After this i tried to replicate similar mileage numbers at the next tankful. This photos is after an entire days commute. Still showing tankful after ride of 100km



Before i start what i am planning to share, here are a few FAQs

FAQs

Q) Are you crazy? Why would you use a bike for a highway commute? It is not safe

A) To answer the first part. Yes a little bit. Anybody who has an obsession to this musical bit for nearly 30 years can be classified slightly insane.

https://www.youtube.com/watch?v=2i7ppYRLmeQ

To answer logically, the commute on a car over this distance on a stretch with is littered with Traffic Signals, Tolls and highly policed Speed trap system is expected to be higher than a commute on a bike. If I do unwell to ride, I always had an option of buses (Pre-lockdown of course).

Q) Why use a duke for commuting? there are always better options in biking sphere for commuting.

A) Several reasons. Over the years I have ridden very few bikes, but in the ones that I rode, only two have felt super engaging, The R-15 and the Duke. In fact ever since reading the reviews by Shumi in overdrive, this was the only bike which actually got me to the dealership to do a test drive. I laid down the advance for the bike after a 2 Km test drive. Have been in love with that bike ever since. When I thought of possible upgrades, I did try out the R3 as well, but even that felt very calm compared to the Duke. This bike has spoiled me for anything above or below its price range.

Q) You ride a duke. How are you bothered about Fuel Efficiency for Christ Sake?

A) This has been the only investment I have done of this magnitude in my life. I love it today as much as i loved it the first day i rode it. I have never mistreated the bike. Red lined very rarely. Hit the rev limiter only once in my life (and that was a shock for me). I like the bike for what It offers. It does everything with ease where the weaker bikes struggle. I am happy with the knowledge that when needed I have always something extra on tap. Never been bothered about fuel efficiency till I had to do these commutes. The need to worry about fuel efficiency came from the inconvenience of fueling up more than twice a week. Would I wish for a bigger tank on this bike at the cost of loss of dynamics. An emphatic no!

[rohitoasis]

Like any experiment, there would be variables which would affect the observations. The problem for any experimentation is that more the variables, the less reliable the outcomes are. So the variables of the experiment are listed below and i have shared my attempts to maintain some constancy in the variables to enable me get a reasonably reliable output.

The Man:
Half Sane idiot who giggles like an idiot at out accelerating the rest at traffic signals and whoops in joy at timing the signal turning green, but then settles at the set speed limit of between 60 to 70 kmph.

This variable has massive implication on the fuel efficiency, when you have a bike that revs to the moon and a slick close ratio gearbox, it is extremely easy to get carried away with the fun and rev the nuts of the bike. It takes massive self control to keep the bike at a sane speed.

The Machine: KTM Duke 200, 2012 Model Year:
- Literature for the bikes show a tank capacity of 10.5 Litres. I have never been able to fill up 10.5 litres on my bike. One a bad instance where i mistakenly nearly emptied out the bike and then filled it till the brim, i was able to fill 9 litres.
- Fuel Low level starts showing at 1.5 litres. If i do fill up the bike till brim at such an instance, i am able to fill around 7 litres at best.
- After the mistake i mentioned in the first instance, i have tried my best to fill up fuel every time i see the low fuel mark.
- Bike serviced at near OCD levels. Once every 3 odd months during the first phase and Once every 20 days at least in the 2nd phase. (At one time, i was also doing the chain service every 500 km as per recommendation, but since that meant service every week, i decided to do it by a gut feeling on when it was needed, Noted that chain service was really evidently required around 1800-2000 km
- Oil Change done every 7500 Km. Mineral for the first 15K km. Synthetic ever since.
- Tire Pressure: I maintain the tire pressure at 28 for the front tire and 32 for the rear tire. Was slightly kooky at the beginning when i used to refill air at every refuel. But now i have limited to do the air filling every week. I have noticed pressure drop of around 1-2 Psi on the front, 3 Psi on the rear in this week on cold days. Around 1 Psi extra drops on hotter days.

I have tried to keep the bike in more or less similar condition over the time period in question.

Payload:
Rider : 74 Kg before lockdown;77-78 Kg after lockdown, a 5 Kg office bag, 2 Kg helmet, Around a kilo of riding jacket.

Lockdown did not help much. So this was one variable i could not control much.

Fuel:
Indian Oil Normal Petrol nearly every time from trustworthy petrol pump. (Xtra premium rarely when normal was not in stock or when i was adventurous enough). Nearly always filled to the brim. Auto cut off happens 1.5 litres lesser than full capacity that i fill. I tend to fill till the lower lip of the fuel tank lid. This difference usually means the difference between me running at low fuel level vs me running out of fuel by the third day of commute. There have been occasions when the pump operator is a bit enthusiastic to pull back the fuel hose and a bit of fuel is sprayed outside. But those are rare phenomenon. So this variable is more or less in control with variability as low as 100ml on the worst case scenario.

I usually fill fuel in the mornings between 0645 hrs to 0700 hrs. So density variation of the fuel or the fuel vaporization if any would not be drastically different.

Commute Characteristics:
There are 2 possible locations to commute to. Our manufacturing plant approximate 45 km away from my house and our sales office 50 Km away from house. I commute regularly to the latter and very rarely to the former. Allow me to brief the characteristics of these commute.

50 Km commute: 10 Km within city limits (Around 1 Km of has obstructions of Flyover construction), Balance 40 Km of this can be done in top gear, But it is peppered with 1 toll, 5 traffic signals onwards and upto 8 Traffic signals on return leg (Few are operational occassionally) and 3 speed cameras. 22 Km within Kerala has speed limit of 80 Kmph. (Need to verify this speed limit bit, conflicting reports say 90 and 100 have come into play. However i chose to play safe, no tickets till date)

45 Km commute: Nearly entire distance is highway. 4 Tolls, 5 Traffic Signals and 3 speed cameras.

This nondescript description above of this variable hides so many hidden clauses within. You have

Traffic variability: Time spent on traffic is one of the worst culprits in affecting the fuel efficiency. When traffic is high on the normal route. I try alternate routes as much as possible.

Time spent on Traffic Signals: Another variable that can affect overall efficiency over entire journeys. The ones inside the city are atrocious and there is no way around these but to wait on them. For the ones on the highway, I try to overcome these hassles by matching my speed to match the green signals. Where i see red signals, i try to slow down to a coast till the signal turns green and the road ahead is clear enough. There are seasonal timings for these signals and i do trial and error for the first few attempts before settling onto a speed right.

[rohitoasis]

Evaluation and Recording of the data.

On the go, I use the speedo indicated speed and efficiency as a guidance on how good or bad the efficiency would be.
A little bit about the readings on the speedo console.

Fuel Indicator : It shows only gradations worth 8 litres. Equally spaced intervals between 8 to 3 litres, followed by 2.5 litres and 1.5 litres. Fuel Low level starts showing at 1.5 litres. If i do fill up the bike till brim at such an instance, i am able to fill around 7 litres at best. The float seems to have a mind of its own on some days. There are occassions when i know i have more than 4 litres but the indicated reading shows 3 litres. But then at the end of the journey, when i go to tank up the next day. It still shows the 3 litres remaining. So fuel indicator is not the most reliable.

Fuel Efficiency reading: Unlike average speed, the fuel efficiency readings are instantaneous mileage readings and the range shown is the fuel left multiplied by the fuel efficiency reading. For example in the below image, the fuel reading is 8 litres multiplied by instantaneous fuel efficiency of 61 kmpl.


I do know that instantaneous fuel efficiency would be nowhere close to the actual fuel efficiency. The difference between actual and indicated fuel efficiency differs between 10% on some days to upto 30% on other days. I try my best to maximise the number in the indicated fuel efficiency. In fact in my experiments, i have been able to trick the computer to show much higher indicated numbers. All you have to do is start while coasting downhill, you can easily get the bike to show numbers close to a Bajaj CT100 mileage, though as you do continue riding, they tumble down to settle at a reasonable number later.

Tankful to Tankful readings in excel sheet:
The effects of all the variables average out the fuel efficiency and the i arrive at those at every refuel by updating the excel sheet i explained earlier. This tankful to tankful range would be a reliable indicator of what i have actually achieved.

ktm duke petrol.xlsx

However i would like to re-iterate that the observations i list below may refer to the instantaneous mileage shown by the speedo console.

[rohitoasis]

Findings

Category 1 Observations : Most obvious ones. These are based on what most of have known over the years.

Speed: Like most of us know. Speed kills efficiency. I remember within a week from first service, we had an Xbhp ride from Chennai to Mahabalipuram. For the sake of the photoshoot, we were riding in a peloton and averaging around 50 Kmph. I noticed an indicated mileage of 57 Kmpl on the display that day. For the next 7 years i have checked the mileage much. I categorise the stages of my riding as below.

1st stage (Most of 2019) when i was obsessed with doing a quick time on these commutes, i used to target 60 kmph average and bike used to average around 70 kmph on straights. During this stage, the indicated mileage of the bike never exceeded 47 kmpl even in the most calm riding of mine. As you can see from the excel sheet. The mileage in this first stage hovers around 40 kmpl. Average time for commute was 50-53 minutes in the morning (Without any traffic) and 55-62 minutes in the evening thanks to office traffic in the evenings. I used this stage as a learning curve trying to monitor the time required between chain service intervals, other minute changes i could see in the bike over the period of riding and work out the optimum schedule for bike service.


2nd stage (The few days we had of 2020) : No matter how careful you are at riding. You do encounter an idiot or two crossing your paths unexpectedly and you have to brake with alacrity. A scare or two in the highways and you tend to be more careful. I decided to maintain my speed between 63 to 67 kmph in the highways. The road works i had to encountered also were nearing completion at the beginning of 2020 and i was able to maintain the same commute time. The indicated mileage would creep towards the 50s and the recordings in the excel sheet show values between 40 to 44 kmpl.


3rd stage Post lockdown : After the lockdown, i resumed the commute in December 2020. I had done less than 200 km in the previous 9 months and was wary of riding. Before resuming the commute, i was trying to find niggles if any had developed and sort them out at the ASC. I was commuting to office once in two weeks in December. Daily commutes started in January 2021. The first shock on resumption of commute was to see how far the petrol prices had gone up during the lockdown. I was now with a goal of trying to keep my expense lesser than 2 rupee per Km. The indicated mileage would reach the 60s and as you can see from the excel sheet, the tankful to tankful mileages now cross 45 kmpl. The commute times more or less remain similar. Road works en route are minimal and i try to save the time by timing between green signals to avoid waiting at signals.


I have not discussed the outlier cases from the excel sheet on purpose and would limit by observations to the averages i noticed.

Lower RPM (Inversely higher gear: Again most of us are familiar with this concept also. However i did not want to miss this obvious observation. In the morning, the instantaneous indicated mileage, starts at around 25 kmpl and gradually rises to mid 40s within the first 15 kilometres (The traffic signalled and tolled section) and then gradually rises towards a higher value as the rest of the journey is mostly the top 3 gears only. I maintain the bike at around 4000 rpm these days. Was around 4300 rpm when i used to travel between 63-67 kmph. Have not monitored the RPM in the earlier stages.

Similarly on the return leg, the first 11 kilometres are within city limit and indicated mileage hovers in the 40s. This rises towards the 50s and settles higher for the rest of the journey.

Throttle inputs and Braking: Sharp inputs to accelerator and brakes are the worst to the fuel efficiency. In my commute i do not have to do such sharp inputs except at traffic signals. Here too, like i have explained, i time the distance between the traffic signals. I have noted that most of the signals with exception of two require speeds of around 50-55 kmph between then. For the two exceptions i have noted above, they require speeds in excess of 80kmph between the signals to meet green at both ends. Being in a speed restricted Kerala, i tend to avoid that and simply coast for a major distance to avoid excessive acceleration and braking. Sometimes i see folks seeing me fully kitted and try to race against me. All of them race ahead only to be caught in the signal. I reach them just in time for green signal with minimal throttle inputs and i tend to feel bad for them.

Category 2 Observations: Not so obvious ones, but still can be explained by some technical reasons. My theories may not be the correct ones.

Vapourisation: This observation comes from the following two methods.
The last day i refuelled before lockdown was on 17th March 2020. After the commute that day i did not use it again for a while. i had 7+ litres of fuel left in my bike. With barely 200 Km done in the 9 months, the fuel depleted faster. Thought i did start up the bike once a week during lockdown, i used to see the fuel level in display reduce drastically. I am assuming this was vapourisation.

Also if you see the excel sheet, for the same commute distance, i have gap of 3 days between refuels every week and another gap of 4+ days between refuels when weekends come in between. The fuel efficiency by tankful to tankful seems to be higher when the gap is higher. Again i know O ring sealing is available on the tank lid and this is only a theory of mine.

Number of start stops: This was a bit counter-intuitive to me. Was originally of the believe that you need to cut off engine at signals to save fuel. However i saw a trend of reduction in tankful to tankful average fuel efficiency. My theory is that, at the relatively mild RPM that i ride, the fuelling is very lean for KTM (Maybe for emission norms). Every start and stop, the fuelling is very rich and with increase in start and stops, i end up using more fuel. I am not very certain of this theory and could be totally wrong.

Engine Temperature: This theory stems from the fact that in spite of having much lesser traffic in the mornings and lesser gearshifts, the best indicated mileage i have seen in the mornings is around 54 kmpl. On the same day evenings, the indicated readings increase by at least 5-6 kmpl. I have also noticed that on the days when i have to stop for fuelling, the fuel efficiency is higher than the rest of the days. My theory is the engine oil takes certain engine temperature to reach optimum viscosity.

Ambient Temperature: An offshoot of the above point. I have noted that higher the ambient temperature, the higher the indicated fuel efficiency. I got a clue from recent triumph service mishap threads that lower intake temperature would cause richer air fuel ratio to be applied by the engine. This supports my finding that leaner ratios are being used at higher ambient temperatures leading to higher fuel efficiency.

Time of the day: Not much to add here that is not covered in above two clauses. But evening journeys despite having higher number of gearshifts provide better indicated fuel efficiency.

Category 3 Observations: The UFOs (Unexplainable Fuel Efficiency observations)

The age of the engine oil: Like i explained earlier, i have always changed engine oil every 7500 Km. I tend to classify this interval in three nearly equal parts. In the first 1/3rd part of the 7500 km, i notice a decent indicated fuel efficiency. In the second 1/3rd part, i find the indicated fuel efficiency dipping by 2-4 kmpl. In the final 1/3rd part of this period, i see fantastic indicated fuel efficiency. In fact the above screenshot showing 488 km range (Translating to 61 kmpl) is very common for me in this third. My engine oil is due for replacement in another 800+ km. I will keep this thread updated if i see this trend repeating after the change. I am barely able to make sense of this phenomenon.

The state (What?): This is real kooky again. Though i have observed above that the indicated fuel efficiency tends to increase as the ride progress on clearer stretches, i have noticed a strange trend in my morning commutes. The stretch with signals and tolls ends at around 15 km from my home. The indicated fuel efficiency plateaus for the next few kilometres and i settle usually between 47-51 kmpl in the next few km. However every time i cross the border and enter the state of Tamilnadu, i see an increase of at least 1 Kmpl every single day! I have tried to guess the reason but i have not yet come to a satisfactory explanation.

Is it just a normal increase in indicated mileage?: Have observed not to be so. Mostly i see the fuel efficiency plateauing around 13 Km mark and near constant reading for next 9 km. This change always happens abruptly.
Am i subconsciously reducing the speed or changing driving characteristics?: I have checked and double checked. That does not seem to be the case
Is the terrain vastly different?: No the stretch has similar elevations and depressions as the distance in the preceding part of journey.
Is the asphalt quality vastly different?: Does not appear to be and i am not an expert to opine on this. If yes, why don't i see a reduction in mileage on the return journey.

I have come up with a kooky explanation to this. The bike is registered in Tamilnadu and it shows affinity to its home state by showing higher fuel efficiency.

[rohitoasis]

Untested theories:

Effect of torquier engines on riding: I theorise that torquier engines would need lesser gearshifts and better fuel efficiencies may be achieved for the speeds that i do. Unfortunately do not have access to other bikes to conduct these tests. Only other bike i have used for the commute is my dads Suzuki Access. I am open to tests if someone is ready to lend me their bikes. I promise not to redline or abuse the bikes. But no bullet please. Not a big fan of those.

Effect of Multiple Cylinders: I theorise that for the same distance travelled, a multi cylinder engine would need multiples of fuel being injected equal to the number of cylinder and i feel multiple cylinder engines would give lesser fuel efficiency for that reason.

Effect of tire pressure: I do not have enough findings at lower tire pressures to arrive at any reasonable findings. Like i said, i refill air every week. But i feel, with lower pressure and higher contact patch. Fuel efficiency is bound to reduce.

Effect of tow: It is close to impossible to find someone who is willing to have constant speed in the 60s to provide a tow without compromising safety while riding. So this theory is largely untested. But when i ride and sometimes get stuck between a reasonably fast truck. I do experience the tow and feel the bike feel a bit more relaxed in the slipstream. I feel this could help increase fuel efficiency.

Parting comments: Not much to add. I know some of the theories i have mentioned are beyond kooky. When i have the best forum available to bounce off these theories and get correct explanations, i thought i better do it here.

Either way, i am not sure this thread warrants this long read. If you are bored or frustrated at my stupidity by now. I Do apologise for having wasted your time.

Also one of the Bhpians is bound to find a rider in the extremely far left corner of the road, riding a KTM like a grandpa in the stretch that i mentioned, you can be rest assured it is me.

[GTO]

Thread moved from the Assembly Line to the Motorcycle section. Thanks for sharing!

Will go to our homepage today

[Rocketscience]

Wow, that is quite some research you did there, commendable efforts there. Personally, i just go with turbo diesels in cars with their way better fuel efficiency with similar performance as compared to turbo petrols, i don't have to think anything, they just are super fuel efficient without even trying.
The only thing i do is when i'am not driving fast, which is 95% of the times since there is no space to go fast, i just cruise on the highest possible gear without lugging, that takes care of everything.

In motorcyle though, i'd say i have been lucky with my r15 v3 and its VVA (basically VTEC), it gives me stellar fuel economy, again without even trying (because of those 2 cam profiles and ample low end torque), this bike i go fast 50% of the times since i only take it out on weekends, at odd hours and on empty roads for pleasure rides, still most of the time it stays in the lower cam profile (below 7400 rpm), the worst i have gotten till date is 45, average is 48.5 Km/l since i bought it with spirited highway driving, with a highway/city split of 70/30.

[silverado]

Negligence.

I had not paid attention to my scooters fuel efficiency much since running was low. The accelerator response was weird and it would "raise" at times and always felt scooter was running rich.

I was lazy to get it checked until one day i noticed fuel efficiency had got lower than 30

I took it to my mechanic and then it was a jammed Carburetor nut
On fixing it, it is now giving me 44-45kmpl.

[PrasannaDhana]

Being a fellow KTM owner, albeit the 390 twins (Both BS4 Duke 390 in the past and BS6 RC 390 at present), here is what I have gotten in actual usage

2017 KTM RC 390

Riding style - mental or whatever term you can call it to rip the engine and keep it at boil for 61 minutes non-stop, completing 117 km, averaging 115+ kmph.

Fuel Efficiency obtained - 17.5 kmpl





The same style of riding in my Duke 390 did not return anything over 16.5 kmpl.

That said, there are two other styles of riding I usually do

Spirited - 7000-9000 rpm
Fuel efficiency - 22 kmpl

Relaxed - 4000 - 5000 rpm
Fuel efficiency - 32 kmpl


There are riders who even get 35+ kmpl from the KTM 390 engine

Beyond factors like cc, tyre pressure, number of cylinders, vehicle weight and aerodynamics, the fuel efficiency depends largely on driving style. I realised that when my Tata Safari Storme Varicor 400, a 2 tonne SUV with 154 BHP and 400 Nm torque, returned me an amazing 15.4 kmpl actual fuel efficiency during the last tankful.



The same car had given fuel efficiency as low as 10 kmpl in the past. Why the difference? - due to the difference in driving styles. Be gentle with the machine, accelerate and decelerate without any rush, operate it in lower rpms as much as possible, the fuel efficiency will shoot up.

This is not just from my experience in two fuel guzzling engines - the KTM 390 and Tata 2.2, but from the experience of numerous cars, among which the most fuel efficient ones are also included.

Examples:

Chevrolet Beat diesel -
Best - 25 kmpl
Worst - 14 kmpl

Maruti Ciaz diesel -
Best - 25.4 kmpl
Worst - 16 kmpl

Renault Kwid 1.0 -
Best - 22 kmpl
Worst - 13 kmpl

Honda CBR 250 R -
Best - 40 kmpl
Worst - 23 kmpl

All figures from tankful to tanful method. Best and worst efficiencies when driven by the same driver (me). My firm belief through my experiences is that fuel efficiency depends on the driver more than other factors combined.

[Nitronium]

That really is some great research!

I find that far too many drivers/riders don't 'coast'. This is a simple technique of taking your foot off the throttle and allow the car to be in gear while pulling up to a planned stop or easing off after cruise speed is reached (and subsequently feathering throttle to maintain that speed)

To get technical:

A vehicle only consumes fuel under two conditions:

1) When the accelerator is pressed
2) At idle, when the vehicle is in neutral

I've seen drivers press the clutch needlessly as they pull upto signals, instead of engaging engine braking (OR) allowing the engine RPM to draw close to ~1k in the same gear they are braking from

[AjayJoshuaN]

Every time the brake is pressed, fuel is lost. Everytime the hand is taken off the accelerator in gear, fuel is lost due to the engine braking destroying the useful momentum created by burning fuel.
So coasting in neutral should improve the fuel efficiency and will also prevent unnecessary higher RPM of the engine for longer periods.
The distance travelled when coasting in neutral is greater than the distance travelled when coasting in gear.
But a predictive driving style will need to be adopted if coasting in neutral, or else, again the brake will need to be depressed when coasting in neutral which will reduce fuel efficiency.

So I think accelerating to a particular speed (when wind resistance is not too much) and then coast in neutral until a comfortable lower speed is reached, and again accelerating back and repeating this process should yield better fuel efficiency, rather than keeping the vehicle in gear and maintain ing constant RPM or using engine braking (coasting in gear).

Bikes do not have free wheeling unlike bicycles, where you can coast freely without pedaling. So the way to mimic this in a bike would be to coast in neutral.

[v1p3r]

Excellent thread! As someone who draws up a quick .xls once in a while for fun, this speaks to me on various levels.

Originally Posted by rohitoasis

Number of start stops: This was a bit counter-intuitive to me. Was originally of the believe that you need to cut off engine at signals to save fuel. However i saw a trend of reduction in tankful to tankful average fuel efficiency. My theory is that, at the relatively mild RPM that i ride, the fuelling is very lean for KTM (Maybe for emission norms). Every start and stop, the fuelling is very rich and with increase in start and stops, i end up using more fuel. I am not very certain of this theory and could be totally wrong.

Yes, start stops decrease fuel efficiency. The engine operates in a transient mode, where mileage and efficiency are lower than in the steady state mode that highway cruising is. It's the same reason why city traffic is worse for mileage than open highways.

Originally Posted by rohitoasis

My theory is the engine oil takes certain engine temperature to reach optimum viscosity.

Correct, once again.

Originally Posted by rohitoasis

Ambient Temperature: An offshoot of the above point. I have noted that higher the ambient temperature, the higher the indicated fuel efficiency. I got a clue from recent triumph service mishap threads that lower intake temperature would cause richer air fuel ratio to be applied by the engine. This supports my finding that leaner ratios are being used at higher ambient temperatures leading to higher fuel efficiency.

It isn't about the ratios. The AFR can remain the same and you can still have less consumption in hot and humid weather. This is because air is less dense then, and as a result less air (and oxygen) enters the cylinder. As a result, less fuel is needed. The ratio, however, will remain the same.

Originally Posted by rohitoasis

The age of the engine oil: Like i explained earlier, i have always changed engine oil every 7500 Km. I tend to classify this interval in three nearly equal parts. In the first 1/3rd part of the 7500 km, i notice a decent indicated fuel efficiency. In the second 1/3rd part, i find the indicated fuel efficiency dipping by 2-4 kmpl. In the final 1/3rd part of this period, i see fantastic indicated fuel efficiency. In fact the above screenshot showing 488 km range (Translating to 61 kmpl) is very common for me in this third. My engine oil is due for replacement in another 800+ km. I will keep this thread updated if i see this trend repeating after the change. I am barely able to make sense of this phenomenon.

Interesting. Oil degradation follows a linear curve, from what I know. It is certainly not in line with a dip and then rise in mileage, which indicates a presumed change in lubricity. There must be another factor at play here.

Originally Posted by rohitoasis

However every time i cross the border and enter the state of Tamilnadu, i see an increase of at least 1 Kmpl every single day! I have tried to guess the reason but i have not yet come to a satisfactory explanation.

From memory, TN is much flatter. The minute you cross into KL and Walayar, the terrain becomes more undulating. This will affect mileage.

Originally Posted by rohitoasis

Effect of torquier engines on riding: I theorise that torquier engines would need lesser gearshifts and better fuel efficiencies may be achieved for the speeds that i do.

This is correct. In fact, manufacturers in the US have used this to their advantage - the 8 (EIGHT!) litre Dodge Viper was classified as a low emission vehicle because it barely needed to go above idle in first three gears to hit certain testing speeds, and emissions were low then. It has 80 kgm or so of torque.

Originally Posted by rohitoasis

Effect of Multiple Cylinders: I theorise that for the same distance travelled, a multi cylinder engine would need multiples of fuel being injected equal to the number of cylinder and i feel multiple cylinder engines would give lesser fuel efficiency for that reason.

This is mostly incorrect. At your level of power and consumption, all that matters is amount of fuel per stroke. You can have 2 x 100 cc cylinders, or 1 x 200, and it will be roughly the same. At higher specifications, reciprocating masses of more cylinders and the ability to rev higher given smaller piston diameters play a role, but that is more focused towards making power. So I would discount this.

Originally Posted by rohitoasis

Effect of tire pressure: I do not have enough findings at lower tire pressures to arrive at any reasonable findings. Like i said, i refill air every week. But i feel, with lower pressure and higher contact patch. Fuel efficiency is bound to reduce.

Correct.

Originally Posted by rohitoasis

[b]Effect of tow: ...
...
I feel this could help increase fuel efficiency.

Correct.

[mvadg]

Interesting, I'm sure we all have gathered this information in our heads but never thought of putting it down in a document. Very analytical mind!
You might want to consider a windshield or even a full fairing for your bike.

[raman.aries]

Originally Posted by rohitoasis

Untested theories:
Either way, i am not sure this thread warrants this long read. If you are bored or frustrated at my stupidity by now. I Do apologise for having wasted your time.

Distinctly remember the day you bought the bike and brought it home.
Glad to see that you are retaining the bike and hope you are not planning to get it replaced.

[rohitoasis]

Thanks for the posts all. I am sorry i have not been able to provide further updates. Nearly drowning in the year end work pressure.

Also i was so happy when i posted this thread that the road work en route was nearly cleared. Our Public works department seems to love to put a spanner to any such good thoughts. The moment this thread went live, they have doubled up on road works covering 60% of existing lane. The distance which i usually cover in 9 odd minutes now takes a minimum 16 minutes to cover for the past two weeks. I was left wondering if my happiness in the post invited the wrath of fate. Was left too depressed to post anything here because of this reason.

Originally Posted by v1p3r

Excellent thread! As someone who draws up a quick .xls once in a while for fun, this speaks to me on various levels.

Excel sheet remains a key source of my livelihood. It is fun doing experiments on it. Though i started as an experiment with my nephew, the more i started adding data, more i started enjoying setting specific targets for me.

Originally Posted by v1p3r

It isn't about the ratios. The AFR can remain the same and you can still have less consumption in hot and humid weather. This is because air is less dense then, and as a result less air (and oxygen) enters the cylinder. As a result, less fuel is needed. The ratio, however, will remain the same.

Thank you for this information.

Originally Posted by v1p3r

Interesting. Oil degradation follows a linear curve, from what I know. It is certainly not in line with a dip and then rise in mileage, which indicates a presumed change in lubricity. There must be another factor at play here.

I am equally curious. Have completed an oil change as of yesterday. For the next month or two and keep updating this thread when possible.

Originally Posted by v1p3r

From memory, TN is much flatter. The minute you cross into KL and Walayar, the terrain becomes more undulating. This will affect mileage.

Towards Coimbatore direction, There is a series of elevation increases immediately as you enter. If anything these should cause minor reduction in fuel efficiency. How i get the opposite, i am not sure.

Originally Posted by v1p3r

This is correct. In fact, manufacturers in the US have used this to their advantage - the 8 (EIGHT!) litre Dodge Viper was classified as a low emission vehicle because it barely needed to go above idle in first three gears to hit certain testing speeds, and emissions were low then. It has 80 kgm or so of torque.

This point was me baiting somebody to lend me a more powerful bike.

Originally Posted by v1p3r

This is mostly incorrect. At your level of power and consumption, all that matters is amount of fuel per stroke. You can have 2 x 100 cc cylinders, or 1 x 200, and it will be roughly the same. At higher specifications, reciprocating masses of more cylinders and the ability to rev higher given smaller piston diameters play a role, but that is more focused towards making power. So I would discount this.

Fair enough. I clearly see i am not using my bike for the purpose it is intended to. Recently after riding the Yamaha FZ which just delivers power in a creamy manner, i am thinking if i would be better off with FZ or MT15 instead of aiming higher for Ninja 300 or CBR300 or CB350 which i was targeting as upgrades.

Originally Posted by Nitronium

That really is some great research!

I find that far too many drivers/riders don't 'coast'. This is a simple technique of taking your foot off the throttle and allow the car to be in gear while pulling up to a planned stop or easing off after cruise speed is reached (and subsequently feathering throttle to maintain that speed)

I find the instantaneous efficiency does appear to increase when i coast a little bit. So i find it effective method to reach a red signal instead of riding full steam and then braking hard.

Originally Posted by AjayJoshuaN

So I think accelerating to a particular speed (when wind resistance is not too much) and then coast in neutral until a comfortable lower speed is reached, and again accelerating back and repeating this process should yield better fuel efficiency, rather than keeping the vehicle in gear and maintain ing constant RPM or using engine braking (coasting in gear).
Bikes do not have free wheeling unlike bicycles, where you can coast freely without pedaling. So the way to mimic this in a bike would be to coast in neutral.

I concur to the above point, you can coast longer in neutral than in gear.

Originally Posted by mvadg

Interesting, I'm sure we all have gathered this information in our heads but never thought of putting it down in a document. Very analytical mind!
You might want to consider a windshield or even a full fairing for your bike.

Originally Posted by Rocketscience

In motorcyle though, i'd say i have been lucky with my r15 v3 and its VVA (basically VTEC), it gives me stellar fuel economy, again without even trying (because of those 2 cam profiles and ample low end torque), this bike i go fast 50% of the times since i only take it out on weekends, at odd hours and on empty roads for pleasure rides, still most of the time it stays in the lower cam profile (below 7400 rpm), the worst i have gotten till date is 45, average is 48.5 Km/l since i bought it with spirited highway driving, with a highway/city split of 70/30.

These posts have gotten me thinking of adding R15 V3 among the options i had indicated in my earlier response.

Originally Posted by raman.aries

Distinctly remember the day you bought the bike and brought it home.
Glad to see that you are retaining the bike and hope you are not planning to get it replaced.

She is showing a bit of age. In these commutes i have too much free time. I keep evaluating various options for replacement. For long i have been planning for upgrades, but due to various factors not including lack of service, i have just not put my money down on so many good options like Ninja 300 and CBR300. Considering i have to cross various speed traps, i have gotten into thinking of something lower in the power ladder.

Allow me to provide an update. The bike has not been feeling smooth enough for the past few days. While i tried to brush aside this by saying this had something to do with old engine oil, Something deep in my guts says there is some extra clearance developed in the valvetrain. I am noticing this loss of smoothness even after doing the oil change yesterday. More or less confirming something else is wrong. Considering the age of the bike, I had a discussion with my earlier service advisor from Chennai if i should open the head and get the clearances checked. He suggests against doing so. I understand his reasoning. The service advisor here in Coimbatore also feels so. May i invite in suggestions from this forum on what i could do at this juncture.