80-100mpg hiway bikes? (travel speed/overstressed engines)

[stillsearching]

By hiway I mean demanding interstate btw running 70-75mph all day even up to 80mph on occasion.

I see some great mileage figures posted for 125 and 250cc motorcycles, but i've heard comments on other boards that if your struggling near the top of their speed range the mileage goes to pot. An example is the Virago vx250 - suggested over 80mpg got me interested, it can technically hit 85mph so I thought it would be a good commuting choice... yet i'm often forced into 77mph flow of traffic situations where I live at times and one comment said that if you cruise over 60mph it will drop down to like 50mpg. (which is worse than 650cc bikes below there) I cant verify this but it drops my interest alot if so. My current hours mean busy roads where pulse/glide wont work but if I can change that it may become so later on alternate hours. A different living location might mean different roads, distance, and travel speeds but this question will still be valid for others.

I'm aware slowing down is one of the best things you can do, and so is aeromodding. If time didn't matter I could ride a 144mpg Honda Dio to work and take twice the commuting time after a 10 hour job to collapse in exhaustion after such a day... What about those of us for whom by road situations or circumstance forces faster travel speeds? I'm still in the process of trying to explore alternate living and work arrangements for a future situation for which i'm trying to cut down to absolute minimum travel cost while still having to go faster speeds.

It's starting to seem like 30+ hp is the minimum for a 70-75mph commuting motorcycle as it is. (unless one gets the hang of making full fairings and such, but just going by rules of thumb to start, people starting with stock bikes saving up for mods, and afraid to drop and ruin their new fiberglass fairing being a young rider isn't an instant fix for all) I'd love alternate opinions, from people here (since i'm tired of the idiocy on most motorcycle boards where i've literally been told anything less than 883cc cruisers for first bikes is for "f_gs and women" so i'm tired of trying to ask them for advice) more concerned about real world mileage. I'd like to know what kind of commuting speeds are "not overstressing" (that is getting advertised mileage figures) for the lesser ~20hp 250cc's and the 13-15hp 125cc's for instance, or even other bikes somewhere in the middle. The Yamaha 400 Drag Star Four was quoted as 32hp and 100mpg (! better than the 82mpg quoted for the Drag Star 250??) in one review, if that's not a misprint. Then that may be at 55mph too.


I seriously want a 100mpg bike, but know that I may not get what I want of course and even if it does that at 55 it probably wont at 70, but how close can it get? Not being overstressed staying at 100% throttle seems important. Going too small may not be the answer is what i'm realizing and smaller displacement bikes may drop faster in mileage and probably engine lifespan due to being pushed too hard. The Ninja 250 sounds like a maybe, even if marginal, it's over 30hp, but I was hoping there'd be more than just one bike that can do that as it seems the only 250 that keeps up in the real world and most of the 650's seem to top out around 60mpg best possible.

If we can keep speed down whether 65mph, or 55mph, how well do real world figures match the (poorly clarified/speeds not listed in reviews by bike magazines) claimed figures over 80-100mpg? Is a typical 250cc standard/cruiser being pushed too hard to maintain 65mph to get the mileage? Is there a best 250cc for actually running that sustained speed?

With some 125cc's often hitting the wall as low as 60mph and nearly all by 65mph can I actually expect rated mileage at 55mph or not overstressing it running that close to the line sustained?

[bschloop]

Get a 250, and do even a few mild aeromods. the boattail trunk is a great one, since it is luggage as well as aero. the Ninja, and the CBR250 will manage 80ish mpg and 80mph quite well. most of the 250 cruiser style bikes won't, although if you changed the gearing they might. the honda rebel for instance redlines at 80mph in top gear. if you are interested in a fairing or trunk, take a look at Craig Vetter's work. Also I am looking to have my own design finished for this summer. I can go freeway speed on a 14hp 185cc bike with fairing and tail in place, and still get over 100mpg. I have a thread here on the project http://ecomodder.com/forum/showthrea...ike-23987.html

Lowering rpms at speed also makes a difference in engine wear. I run 25% taller gearing on my bike meaning that the engine is now turning the same speed at 75mph as it did at 55mph stock. This reduces wear on the engine, and in combination with better aero gives better FE. (note that this aggressive of a gearing change is only advised in combination with matching aero improvements).

[alvaro84]

Originally Posted by stillsearching

An example is the Virago vx250 - suggested over 80mpg got me interested, it can technically hit 85mph so I thought it would be a good commuting choice... yet i'm often forced into 77mph flow of traffic situations where I live at times and one comment said that if you cruise over 60mph it will drop down to like 50mpg.

I know this problem too, but fortunately I can take a slow route (I work in 12-hour shifts and live ~14mi from my workplace - sometimes I even do this commute by bicycle, but never in night shifts, the way home in the morning would kill me - but going at like 30mph doesn't make it a too long trip).

We have a 250 and 650, and both can do 80+ mpg and 80+ mph - but no way they could do it at the same time. The 650 seems to do better at higher speeds, and both are somewhat better than the Virago you mentioned (my high speed tank experiment gave me 57 mpgUS with Teresa, mostly done over 80mph), but I think aero mods would be the key to get better FE at high speeds. Leaving mods alone, a new CBR250 with its full fairing may be able to do it, that's a nice efficient machine.

[wmjinman]

I had an '82 Honda 450 Nighthawk when the nationwide speed limit was still 55. With a clear "PlexiFairing" on the front, I could consistently get 75 mpg. However, it's top speed was only about 70 with that fairing.

Then a few years later, when the speed limit was 65 on the interstates, I tried to take a trip, and had a lot of difficulty just maintining 65 (with a passenger), and my mileage plummeted. As I recall, I was getting in the 40's and was horrified. It wasn't until later it dawned on me that I was basically running that poor bike "flat-out" on that trip. No wonder it's mileage stank.

So from that experience, I'd say yes - "pushing" a small(er) bike to the limits of it's ability could very easily backfire. Of course, if you just drove slower..... If I'd kept it down to just 60 on that trip instead of 65, I'll bet things would have been a lot different.

It was a nice bike, but eventually I decided bikes weren't for me. It was actually my first attempt at a "super high mileage vehicle". Now, all these years later, I have my second attempt - my Suzuki Swift "White Gnat".

[bschloop]

I tried to take a trip, and had a lot of difficulty just maintining 65 (with a passenger), and my mileage plummeted.

Riding two up is a completely different horse since you are adding about 30% more weight, as well as more drag.

[alvaro84]

Originally Posted by bschloop

Riding two up is a completely different horse since you are adding about 30% more weight, as well as more drag.

Yet it strangely doesn't change top speed too much according to my experience, and the change in FE is within 10 percent too.

Acceleration suffers greatly with our 250.

[renault_megane_dci]

What is your budget ?
If not tight, the new Honda 700 is your best bet since it is tune for FE.

Personnaly, to cruise around at 80 mph, I"d take at least a 500 faired bike and make it pull as big a gear reduction ratio as available over the counter.

But for longer trips, maintenance quickly start to be an issue so belt or shaft drive are a must.

Older design 2 valvers seem to have an advantage like Ducati's or Harleys.

[stillsearching]

My budget sucks. If i'm lucky i'm hoping to find a ninja 250 for maybe $1500 or so, and I dont know what sprocket changes and the rest will cost, but I was guessing they werent $50 jobs. Everything I own except the first car has to be under $8000 or so of additional licensed vehicles including trailers but not bicycles (and even that is pushing it, $6000 be better) until i'm through college and masters courses taken at half time loads or I lose a state health insurance subsidy with lethal consequences.

to bschloop, i'm aware the 250's "can" do those speeds, but what i'm wondering is are they so wound out at that speed that you no longer get the mileage? Or do they get 80mpg and 80mph at the same time? :P I'm told a ninja 250 actually will run 70-75mph all day - i'm just curious what the mpg is at those speeds, as opposed to those running slow. Anecdotes from people seem to indicate maybe 60mpg. Whether the more powerful 250cc cruisers could do better i don't know, a V Star should top at 80mph too im told. Usually I see quoted mileage figures for motorcycles, which seem to be an EPA city cycle, I don't know if anyone tests a highway cycle, or looks into how it drops at higher speeds. That's what i'm really looking for here. Same with cruisers - many can hold the speeds but I don't know what happens to mpg at those speeds. For the 125cc's there are enough travel legs that I can run 55mph that the addition of one, if it gets another 20mpg or something, probably will pay for itself in 3 years. Yet 55 is so close to the 60 these usually seem to top at, I wonder whether they'll get the advertised 100mpg at 55, as opposed to around town. I suppose I can track down each and every single motorcycle looking for forum boards for each one finding those who have tested them like that, but there's dozens of possible models and year variations. :-/

I had someone privately smarmily tell me before to just not drive so much or so fast if I want to save gas or move closer - the reason that's just not possible is that I need to be near medical services and travel to others at least 6 days out of 7 every week which seriously limits my flexibility. Main work, college, and essential side jobs without which I couldn't pay my bills and which fuel eats most of my profit on normally are the why of the rest. If I had 28 hours in the day I could commute slower too. I lose more cutting those things out of my life to just 'not drive' so that's silly. Part of why i'm having to spend so much time thinking up a 'stable' of flexible transportation options to the point I practically have a database, with pages and pages of info and notes i've taken now, is because of the unavoidable need to drive 20-50k miles per year under varying circumstances- work, school, med treatment, side jobs worth doing if I can transport physical objects cheaply enough etc. The more things i'm capable of moving (ie my questions on towing with mpg elsewhere, and heavier vehicles, and making one vehicle do the work of two like a caprice pulling 7-10k) and the less the fuel costs, the more side jobs I can do to better afford my biggest problem of uncovered medical expenses. I just felt I should explain this because someone asked why I was seeking such diverse answers on every level of everything.

Combined with rising fuel costs, I expect to spend more on fuel than rent over the next ten years. Electrical remains an unknown with the shutting of coal fired plants and this 'carbon tax' nonsense, and the infrastructure for public CNG refueling doesn't exist here otherwise the cheapness of that fuel would by itself make alot of things more workable. I'm hoping to try a biofuel project soon where the SVO could provide most of my needs if I dieselize everything but that may or may not work at all and i'll be limited in gallons per month to do everything so even if 'free' fuel I cant run a 3/4 ton Cummins everywhere. I hope to add a vehicle for basically any transport niche that will pay for itself within a couple years, not cost too much up front, and hope to have backup plans for if fuel prices rise impossibly high such that it's better to take 3 hours commuting per day instead of 1hr just to avoid the 2nd job needed to pay for the fuel.


Hence at the moment it's entirely possible I could end up with a 250cc, 125cc, 50cc scooter, and electric assist bike if I can get into each cheap enough (the only thing that isn't an option is human power alone, cant arrive most places all sweaty and panting), and each is able to pay for itself in extra gas savings within a few years or at least should be researched to be options for when gas hits a certain price and looks like it will stay that way for awhile, my spreadsheet says it makes sense to add to the stable. But that's assuming that the real world mpg figures as i'm forced to drive them actually work out. If a Honda Dio 50cc scooter really can pull 144mpg in the real world, that justifies having even if I also have a 100mpg motorcycle. If the 125cc's can get 100mpg at 55mph/it's not overwound, I can use that for enough legs of weekly errands requiring the highway that it's worth having even if I already have a 50cc and a 250cc. If a 250cc can get 70mpg running 75mph that pays for itself over a geo metro.

I hope to eventually aeromod everything but I may not be able to right away unless I get cheap scrap or better fabrication skills. It's also possible if aeromod stretches the capability upwards I might be like the guys with 80cc 80mph 200mpg scooters doing absolutely everything or maybe a 3.5hp chinadiesel in an aeromod scooter will give me that. I can later sell a few things, which is fine, as bikes rarely seem to lose any value. :P Until i'm more confident of my ability to make something like that work i'm still trying to have backup plans though.

Gear changes for everything i'm potentially in favor of, my main quirk is still that desire to stick a trailer behind absolutely everything, since "moving stuff" is half of the miles I need to normally do. If it kills 1st gear starting with a heavier load I may not be able to do it yet i'm still researching how feasible trailering anything by two wheels even is let alone what mileage I would get while trailering anything - that again changes all the above, I might aeromod one 50cc scooter but once a 2x3 trailer is behind it moving the things I have to i'm back to 50mpg and 25mph or something, so I may still have reason for a 'stable' as the situation demands. Sorry for length of my post just hoping this explains some to those who have seen me post in every forum, on everything from bikes to semis.

Basically I have some time now to do research that I wont later, which I was already stuck in before being eaten alive by fuel costs. Once I have a "system" figured out where i've calculated every variable of miles I might need to drive under a few variable circumstances I expect in the future, and fuel prices from $3-15/gallon with a plan of when I have to do one strategy or another, I can just follow that system of "buy this, sell that" or similar having already preresearched which motorcycles and scooters to look for as things change, instead of struggling to work out such a system later when work, school, commuting, and medical are expected to account for up to 105 hours per week for at least the first two years leaving zero time to even catch The Simpsons anymore.

[renault_megane_dci]

A 90's basic 250 (my GN) ridden 1/3 in the city and 2/3 on the highway at speeds no lower than 60 mph (and no faster than 80 mph) with the only mods being a gear ratio swap (15/43 to 16/39) and a small windscreen returns something between 75 and 80 mpg.

That being said, a bike tuned for high MPG at higher speed is not gonna be appropriate for trailering.

You could always carry a large cargo box as part of the aero package but trailering seems so odd and basically dangerous with a bike ...

Things is you want stuff at each end of the scale but to optimise either FE or carrying hability, you'll need to do some compromise on what you expect.

Bigger FE / smaller bike / limited carrying load
vs
Better carrying load (though not too impressive) / bigger bike / smaller FE

[sendler]

Fuel economy is a new concept in the 80 mph motorcycle world except for BMW who has been good for decades. Manufacturers were mainly interested in making high performance toys. The Ninja250 is cammed for high rpm power but is small enough that Vetter style aero mods can get one close to 100 mpg at 65 mph. Honda has made a big commitment to fuel economy with the NC700X, the upcoming CBR500R, and the CBR250R. All of which can break 70 mpgUS right off the showroom. I get 95 mpg on my CBR250R when riding full tuck but some taller riders that sit up run out of power at 80 mph. I can get 75 mpg at 80 mph on a trip. Similar aero mods will push this bike 15% past what the Ninjas can do. My Honda PCX150 scooter tops out at 65 mph and gets 98 mpgUS at 50 mph. Some 125cc air cooled bikes in India top out at 50 mph and get 140 mpgUS at 35 mph and cost $1500 brand new.