Team Motorcycle battle plan
 

Congratulation team, we are number 1 with 68,52 MPG :thumbup:

That is 5 MPG more than our second in competition : team diesel.

We are also 15% above EPA wich is good but not as impressive as the third in competition : team Metro @ 42% or team Honda @ 52%.

So we picked the good vehicles (light and efficient at least on a power per litre point of view) with plenty to gain on an aero point of view and easy hypermilling techniques : resist the urge to let 'em sing !

But let's be honest, on a MPG vs vehicle weight ratio or MPG vs potential number of people on board, we suck !

So if you guys are up for a friendly competition spirit, let's discuss the topic with a team point of view.

My first analysis is we lack our champion in the team, Euromodder for example.

Second item to think about is engines.
Motorbike engines are too powerful hence wasting gas.
Why is that so is because they have high power per litre ratio and narrow power band and the need to have narrow gear ratios, the lack of ratio being made up for with the high rpm potential.
What about shorter cams with high compression ratio ?
Can it do for a harsh ride with rear wheel lock when downshifting or whatever else ?
The target would be to make them pull the same torque at a lower RMP.

How can this be done ?

Sorry, I'm not the best person to ask :)

But I have some thoughts too. Especially that I have a 'too strong' engine built in Teresa (I guess 98% of Hungarian bikers would say it's weak, lol :D).

I think it really could be improved by lowering rpms, it is really unusable (gives a pinging noise) under 2500rpm, which is quite a revving for a car engine. I suspect that with thorough engineering (or, maybe a simple power commander would do, if they missed this point in the design) it could be possible to go lower, even with a single cylinder, but I'm eager to invest with unknown results.

But as I'm stuck at/over 2000-2800rpm (depends on the used gear), I don't see the point in making taller gears in my particular case. 5th is already unusable under 70km/h (~45mph).

(My workaround for this very problem is Pulse&Glide, which I often do)

Anyway, Teresa doesn't really have high power per liter ratio (50hp for 652cc), and the redline is at 7000 (or 7500, I'm still not sure, and I won't test it extensively :D), very similar to a small gasoline car :D Compression ratio is 11.5:1, no complaining here :)

Anyway, it would be nice to change something, my girlfriend will have the front sprocket changed on her Hyosung GV250, so I'm potentially losing :eek: :D

Aero modding is another interesting thing, and it's another field where I'm reluctant to tread, just because of aesthetic/convenience factors. I know that sitting upright in the wind is a big no, but I'd hate to lean on the 'tank' for long, and I'd hate to drive a semi-closed box which used to be an honest motorcycle one day :confused: Heck, I'm not even willing to mess with the unique F650CS design :confused:

No, I'm not a good modder, I guess :confused:

But you have the best % improvement over EPA of the team and least MPG so you are basically our champion.

You are also a good example of the particular issues of motorcycles on a MPG improvement potential POV.

BUT being our champion, maybe you can help us improve our hypermilling techniques ?

Maybe :) And I may should invite my girlfriend (shiNIN is her nick at other places) as she has more experience with our GV250.

Anyway, in our 'house competition' my plan is to change tires. I haven't had a single 90+ mpg tank since I have these Heidenau K73s, so I can hardly wait for the front to wear off... bad that there's no info about motorcycle tires' rolling resistance.

Now I think a pair of Michelin Pilot Road 3 would be better, it has a harder compound in the center so it lasts longer - at least the rear should last much longer, I'm consuming the 3rd K73 rear with the same front, and it's not even the end of its life! I hope the Pilot Road is better at RR too. Metzeler Z6 was clearly better (and took higher pressure), but felt somewhat unstable around freeze point.

Pressure: I use the K73 at ~2.5/2.7 bars front/rear (~37/40 PSI) while the Z6 didn't sensibly distort at 2.9 bars / 43 PSI.

BTW, my "EPA" numbers aren't based on EPA tests, they're just factory data for 90 and 120km/h (~55 and 75mph) constant speed cruising. There's nothing about layman's city driving, for example - even though I'd be curious.

OK, I can still use some more 'realistic' data from Fuelly:

BMW F650CS MPG Reports | Fuelly

Does the GN250 has any EPA data anyway? I don't know the model's history, but as it's an old one, it may have been discontinued even earlier than F650CS (which was in production only between 2002 and 2005, what a shame! Good that Honda has the NC700, which seems to fit ~ the same needs - though it's heavier than any F650).

GV250 fuelly data:

Hyosung GV250 MPG Reports | Fuelly

On hypermiling: My very sensible experience is that coasting when you need to slow down is a huge factor. I don't think it's anything new :) After 111000km Teresa's dropout bearing died and I hardly used the clutch except for shifting gears, and you can see my last two tanks: the difference between them is rather large.

I always P&G downhills, I FAS when I expect to glide (or stand still) for at least 30-40 seconds and traffic permits. I have 3 such FAS points on my usual route to work along the ~23km / 14mi. And another, where I don't even turn on the ignition key, so I have to add that 800m (0.5mi) to the trip meter every time I roll down there - we live near a hilltop so I can call it potential parking, along a dirt road with practically no traffic.

I shift as early as I can, it's ~3200-3500rpm, depending on the gears. From 4th to 5th sometimes I even rev more, especially when I climb a hill with a passenger. We had an interesting discussion here at ecomodder about the effect of higher (or too low, to be more precise) revs, and I tried to P&G in 4th on one commute, staying over 3000rpm, but not having a trip FE display, I'll never know the result on FE... and I didn't experiment with it more, because the drive belt (which wasn't in the best shape) began to lose its teeth, exactly over this experiment.

Because I started to accelerate very gingerly after losing a bunch of teeth and almost never shifting to 5th (the latter is surprisingly good at winter, staying at appropriately low speeds, like 60km/h at max), and that tank became worse too... accelerating without proper load looks bad for FE too. I can imagine that even accelerating at much higher revs is equally good too as long as you shift into the highest gear immediately when you reach the speed you want to hold - or start gliding.

The other thing the belt made me stop is bump starts. I just can't do it really smooth. I've become much smoother along the years, but I just can't bump start that large cylinder smoothly, and I'm afraid it contributed the belt's premature death too (I call 41000km premature, the previous one lived for 63000).

Also, I hate to engine brake, I only use it for speed moderation on steep downhills, where I basically trade gas for brake pads and discs... except I have one trick I sometimes utilize: I turn off the kill switch while engine braking, forcing Teresa into DFCO. Beware, it won't work with carbureted bikes, and it will probably have very unpleasant side effects. But it really needs a long, steep downhill, otherwise the 650 single has a too strong engine brake. And very uncomfortable. Just imagine, I cruise along in the city at, say, 2600rpm in 4th, and I want to slow down. The engine will stutter at ~2000, so I can't engine brake for long... shifting back to do so is out of question, to clutch, shift, use gas to rev match, use more gas to slow down (no, she won't easily go to DFCO)... no way. I just glide and use the friction brakes when I can't do anything else.

Hm, these are the machine related tricky things. The common sense part is very similar for any vehicle, I guess. Don't accelerate too much if you know you'll have to stop, look ahead, anticipate, keep longer distance, time lights if you can, don't speed... these are the same.

Climbing hills is a tricky part too, and it can be very different with different vehicles. For me climbing up at a steady speed, accelerating at the crest, gliding (or P&G-ing) down seems to work the best, but it's again some vague feeling, lacking the proper instrumentation. DWL is not that good with such a strong engine with strong braking ability and narrow rev band. Uphills I'd have to shift down very soon and the other size wouldn't accelerate back to my normal speed, I wouldn't even reach my upshift speed. Really, the engine holds me back on a decline once I shifted back to 4th, even with the same throttle position.

(Oh my god, I hope there's SOMETHING useful in this wall of rant...)

Nothing new but it is good to have 'em in a single place.

The more I think about it, the more I am impressed with you hypermilling a big single to such good results.

My personnal best on my XF 650 Freewind was 4 liters per 100 km but again, it was more a toy than anything else ...
I loved it but I would never try to hypermille it ...

Perhaps we should address the elephant in the room. Someone (who we won't name) is running around on a bike which is larger than any two other bikes on the team. Another problem is that this jerk is driving like he stole his bike. A third problem is that he has an electronically controlled clutch, which makes coasting impossible.

I say we hang him in the public square. Who's with me?

Several point :
My contribution is not about winning (we're already winner and there is nothing to win anyway), it is about chatting about ecomodding bikes with a different angle.

I have no problem with your bike or you in the team (is it really a team ?), actually, I am interested in ecomodding my bike but I am a very lame hypermiller : I always find a very valid reason to road race my bike.

I have been throught several approach of riding bikes so far (and I am not set on my current approach) but the line was always : have fun

I think it is all about what we use the bike for.

As stated in an other post, your FJR is very good at what it is designed for : Gran Turismo.
And a Gran turismo much more fuel efficient than with pretty much any car of the same performance.

Honestly, I wouldn't buy one but then I have only a 12 mile commute.

Anyway, riding a FJR like its stolen, you're either very brave or very stupid ... ;)

I think the main hang-up with our motorcycles is the cam. Manufactures want high HP-weight ratios to sell bikes, but this also means inefficient engines with high top-ends. I shudder to think what a modestly geared up Ninja 250 with a more reasonable cam could do for mpg. Since this is the most commonly used bike for modding, is it possible we as a group could go in together to have a batch made? Personally I don’t have the knowledge or skill to design a better cam, I only know enough to know it could be done. That being said, with fuel injected bikes like the Honda 250 this option is less attractive because of tuning issues.
Does anyone else think this is viable?

I couldn't agree more. Therefore I don't see any problem with a big one here.

Quite the opposite here - I find my fun in hypermiling, but modding is not really my cup of tea. Using a bit higher tire pressure doesn't need any extra, trying another windshield angle did not do any good, and the kawasaki front wheel (not done by me, but my mechanic) is not for FE reasons, but because I hope it's more durable than the original one. To be honest, I can't even cut a piece of paper straight, I'd be no good at custom mods...

Even Teresa is kind of too big for the 2*14-mile commute of mine (a 125 would be perfect here, these are all nice back roads and village and suburban roads), but she's a multipurpose bike, and have been my only vehicle for almost 4 years. I have crossed the country 2-up with her, sometimes with a top case full of books or other heavy luggage so I don't really regret my choice. Oh, and I almost forgot - I started with a 2*38 mile commute mostly on a motorway, just moved closer to my workplace later.

That's the spirit !

How about checking if the exhaust cam is hotter or "colder" than the intake ?
If it is colder (as in less duration) maybe a swap is possible with the inlet?

Overlap goes with high power per litre engines and it is what kills FE.
If we could reduce overlap, we might see a very good improvement (as well as a big drop in powwer or max RPM).
Together with less duration (higher dynamic CR) and it would be FE heaven