Buying a bike for MPG/Vetter Challenge, what would be your favorite?
 

One of the issues for the Vetter Challenge that is being discussed in various places is deciding which platform, or donor bike to use. Some people want to use thier existing bike, some want to get the "best", some want the cheapest and most common. This whole bike choice thing will probably never be resolved completely as the optimum existing bike doesn't exist to suit everyone. We only have what is out there now to choose from. The best we can do is get one that is good enough for our purposes, or slightly modify one towards optimizing it for the purpose of high MPG.

The important technical factors in choosing a donor bike appear, in no particular order, to me to be:

• Highly efficient motor, about 250cc seems good, some are better than others.
• Chain drive, ability to change gearing, and chains are more efficient than CVT and shaft drive.
• Low seat height, reduces frontal area and corresponding total drag. IIRC 24" is the lowest legal height in most states, though I've NEVER heard of someone being ticketed for too low of a seat.
• Air or water cooling. Water cooling allows higher compression ratios and being able to place radiators where you want them among other things. Air cooled are simple, non-toxic and noisier.

There are also non-technical and practical factors like:

• Common availability. Hard to find out of production bikes may fit the bill, but only for the select few that can find them.
• Cost. This threshold varies from person to person.
• Ease of modification. Some bikes will be easier to modify than others for mpg and aerodynamic goals.
• Chinese. Some don't want to send money to them, some don't care, some question thier reliability. It's up to you. Darn inexpensive, if you wrench your own rides.

Craig is thoughtfully trying to design something that could be used on many different motorcycles. The Vetter streamliner front fairing blocks alot of wind so water cooling with this would probably be needed.

Alan's Ninjette with only the Vetter tail actually gets better mpg than Craigs fully streamlined Helix. Whether this is due to a more efficient engine and/or drivetrain or some other factor hasn't been dithered out yet. It does demonstrate however, that an un-optimized front fairing can still work with a good tail section. This discovery may open up some choices to include an efficient air cooled engine with a minimal front fairing and a tail, as I see it.

Below is a list of some of the more common freeway-capable bike choices and salient features that have been posting 80+ mpg figures. It's not a complete list as you all will have additions, I'm quite sure.

• Kawasaki Ninja 250 (1986 through '07 are best). Very efficient water cooled motor, very common, very cheap, changeable gearing. High strung motor not optimized for low speed operation, higher than optimal seat height, cramped sportbike leg position for some.

• Honda Helix 250. Pro: Craigs paved the way! Average motor efficiency, water cooled, super easy to ride, common, cheap, changeable gearing available through only one source, low seat height, comfortable, Chinese copies still made. Tiny 10" wheels, inefficient CVT transmission.

• Honda NX250. '88-'89 I think, very efficient water cooled motor, changeable gearing, comfortable upright seating. Hard to find, high seat height, hard to find, doesn't have common street tire sizes, hard to find.

• CBR250R. Since 2011, very efficient low friction water cooled motor designed for mid range, feedback fuel injection, changeable gearing. New, expensive (relatively), few in resale yet, high seat height.

• Yamaha V-Star/Virago 250: Since 1988, Very efficient long stroke air cooled motor, common, cheap, changeable gearing, tolerates taller gearing well, comfortable low cruiser seating, Chinese clones are cheap. It's air cooled.

• Honda Rebel 250: Since 1986, Efficient air cooled motor, common, cheap, changeable gearing, comfortable low cruiser seating, most cramped small cruiser. It's air cooled.

• Suzuki DR200/Honda CRF230/Yamaha XT225/TW200/Chinese 200 dual-sports and Motards: Lumping these together as they are very close in performance and mpg results. Efficient air cooled motor, common, cheap to very cheap, changeable gearing, comfortable upright seating, torquey durable motors. Tall seat height, 15-17hp is JUST BARELY enough without aerodynamics, air cooled motor.

What is your favorite among these?

Keeping the availability, cost, practicality issues in mind, can anyone think of a better bike platform for the Vetter challenge other than these? If so, please post.

-Garth

Ninja 250, install better exhaust, flatside carbs (Keihin FCR) small pod air filters, taller gearing, streamline it, have it dyno jetted. Should be extremely easy to hit 100 mpg.

At least, this is my bike, and mods of choice when done modding the car.

A member here posted a 90 MPG highway mileage on his 2011 CBR250R with a 15 tooth front sprocket and a tuck on his daily commute. I think that is at something like 62 MPH average speed. There are some salvage rebuilds coming into the market for $2600.

The basic CBR with modern fuel injection and feedback fuel system is supposedly about 10 MPG better than the Ninja, but you can find cheap Ninjas just about anywhere.

regards
Mech

beater911
The Ninja 250 is the bike that fits the critera the best. price;/performance and modability.
The "problem" with aircooled bikes is the management of the cooling air. If the cooling air is managed they are fine. Good management of cooling air requires ducting to and from the cylinder and head.
The next best choice would be a single cyclinder duel sport bike motor from 200 to 400cc. Look for something that has a bolt on rear subframe; if they are available on none racing type dirt bikes, that can be replaced with a rear subframe with a lower seat height.
The nice thing about the 250cc V-twin bikes is they start with a low seat height. An other consideration is; can the stock handle bars be easily replaced with narrower ones for better aero.

Garth, Excellent post!!! I think your list is pretty comprehensive. I think the Honda CBR 250 would be the best choice if price were no object or as time passes and they become more available through the used and salvage markets. But since cost and availablity is a major factor for people like myself I will probably end up with a Ninja. On CL, Ninja 250s outnumber the other leading candidates by probably 10 to 1 at least.
Even though I've looked only at Ninja 250s so far , I am stilled intrigued by the Virago 250's better low-end torque , lower seat height and better fuel economy in stock form. The only issue would be getting adequate cooling with streamlining in place. Alan Smith had big problems with his Honda 230 before switching to a Ninja 250. I wonder if you couldn't leave the engine exposed and still get great FE or design in efficient cooling ducting or an electric fan.
I started looking last week for my future Vetter Challenge bike and hopefully will find a good candidate soon.
Garth, Thanks again for all your great work during the Las Vegas to Barstow Vetter Challenge, it was great to meet and spend time with you.
all the best , Vic

I'm starting to look for a Ninjette.

Kawasaki also used the same engine in the 250 eliminator. It was a cruiser style. Just did a search of allofcraigslist.com and only came up with one.

A company called ecotron offers a fuel injection set up w/a tunable ecu for the 250 Ninja. I wonder if an Mpguino could be set up to read it.

Kirk

That is a pretty decent list IMO.

The Ninja 250 is the clear winner when price is a factor. The engine has proven to be pretty efficient, even though it makes its peak power and torque WAY up there.

As far as the Ninja mods BHarvey suggested - I have to disagree. I don't think you'd want to go that direction from a mileage perspective. From what I have heard about flat-slide carbs, they don't like small throttle opening. I would think you'd want to drop down in carb size to increase the velocity at smaller opening while sacrificing some (unneeded) top-end power. Pod filters would kill any positive intake pulses (and your throttle response and mid-range power). Ducting in warm air to the airbox would be better IMO. You want small exhaust pipe dia and some amount of backpressure, so I wouldn't mod the exhaust system.

The CBR250R would be better, but not very easy to get a cheap donor if you were planning to scrap most of the body work.

A 250cc single enduro might be a good choice. Most have 5-speeds and air cooling, but there are a few that would work. Since you would most likely be adding full custom body work, not having any to start with wouldn't be an issue. You would want to drop it down, but a KLX 250 has a lot going for it - water cooled, 6-speed, and F.I. Should run pretty well at lower RPMs when cruising with the addition of aero body work and tall gearing. Not many used to choose from I would expect, but I don't think they are very expensive used if you can find one.

EDIT: It looks like only the current standard model KLX (not the S or SF models) are F.I. Saw a couple 2010 models listed on CL in my area - both for around $4000. So they aren't really "cheap" I guess. Other than the NX models, I'm not sure how many other 250 Honda singles are water cooled.

The older Honda NX250 is water cooled and 6-speed as well, just obviously no F.I. I've seen them on CL occasionally.

Don't know much about the others, but from what has been proven in past competitions, water cooling is a requirement when going full-aero.


Jay

BHarvey: Sounds like most of the mods you listed benefit max power production. The FCR is a great very tuneable carb no doubt, but I could only find a round slide kit, and those were 31mm listed as *Race Only* vs the stock 27mm. Not sure if there would be a FE benefit there vs tuning the stockers properly. The pod filters are great for top end, large air box volume is beneficial for low and mid range power torque production but there could be a reduced air flow friction benefit though. My GPz550 had pods, they were loud and didn’t really help FE much if at all with Yosh pipe and a jet kit. For 90-100 mpg, the horsepower requirements are far less than what the Ninja 250 can easily make in stock form.

Old Mechanic: Good idea to look at salvage rebuilds! If the broken bodywork will be replaced or covered with a Vetter fairing anyway that is a cost that can be avoided. I’d not buy one without personally inspecting the mechanical and structural parts though.

Redyaris: I know you are doing great things with the GS and Ascot. Larger motors turning slower can also return stellar mpg figures. The air-cooled direction I was hoping to address by the fact that Alans Ninja with the more or less stock front fairing is a lot like the stock air cooled GS. And it tops the gasoline powered FE list in the challenges. This supports the idea that an air cooled design could still work well.

Keep in mind that air still needs to be ducted to a water cooled engine radiator for it to cool the engine.

Vic: I just thought I’d post this to try to get all the heads in the same place about bike selection. If the frame can be easily modified for a low seat, the Ninja is no doubt the obvious choice right now falling within most of the constraints we’ve put on ourselves. I’m sure you’ll find a suitable donor soon. Hope to meet up with you again, next time I expect to be riding.

FXSTi: Right on, the Eliminator is really hard to find and since nobody has mentioned it, just the rare NX, I didn’t either. Other harder to find high MPG bikes that come to mind right now are the Kawasaki GPz305, CSR305, KZ440, Suzuki GN400, GN250, Yamaha SRX250, Honda XL250 1982+. The BMW 650 Rotax is quite fantastic as well I understand.
Wouldn’t that be fantastic to have an Mpguino readout on the bike!

So far it looks like the Ninja 250 is the crowd favorite. Easy, cheap, works pretty well though not optimum.

For big-effort, maybe the optimum current bike would be a modified, lightly crash damaged CBR250R made into an Alligator wannabe, then streamlined? Not exactly easy but should produce an easy 120+ mpg under the Vetter conditions. Brushing up on aluminum welding skills would be a good idea for the frame and swing arm changes.

Anyone have other ideas for a good bike to start with?

I was very surprised when I found 2 Kawasaki EL250's just within a few hundred miles of where I live. Especially this time of year. I hope someone can make use of one, if they're still available.


1988 Kawasaki Eliminator 250

2008 Kawasaki Eliminator

Good catch. Those didn't show up on allofcraigslist.com. I must not have used the right search term. Does anyone know if the 2008 was revamped at the same time as the Ninja?

Kirk

I don't think the 2008 Eliminator (US version) is 250 CC. Not sure about the earlier models as they were available up to 1000 cc if memory still serves me correctly.

The 2011 CBR250R is steel frame and swing arm. I just checked them with a magnet.
The rear suspension monoshock is located just behind the engine and the whole rear of the frame could be removed and modified fairly easy. While it may not be significant also consider that the CBR produces about 10-20% of the emissions of the Kawa.

The fixed headlight (doesn't move with the front forks) helps with streamlining. Ninja is probably the same.

Another factor is the cooling fan for the radiator. If you reduce airflow too much the the fan will come one (temp controlled), something that you could monitor to optimise your aerodynamics.

The CBR is optimised for torque, while the Ninja has greater power and engine speeds over 8500 RPM that is not really ideal for mileage. Also the larger single cylinder looses less heat to the cylinder head and walls.

Mine has just hit 3000 miles and the difference now compared to brand new is significant. Also much longer service intervals, like 6 k oil changes.

Disadvantages of the CBR is the speedo reads off the rear wheel, so sprocket changes can not easily be re calibrated in the speedometer and odometer.

The Kawa as well as all motorcycles will soon have to pass emission control standards that will require fuel injection almost certainly. The carbs are old tech and not very green
if that is important to you. Since you are already going to toss the fairings, you might find a naked CBR cheap without frame damage. I'll be looking for one in my area for the same purpose.

regards
Mech

http://www.salvagetitlecars.info/aut...s/HONDA/CBR250

here are a few.
regards
Mech

Good question - they don't look the same from those photos. I'm familiar with the older style, but not the '08 version.

Prices are right for a project!


Jay

When tuned, small throttle openings are good. FCR's atomize fuel very well allowing a little leaner AFR than other carbs, without running hot.
The small pod filters give the carb the 'impression' that it is smaller and a smaller filter 'requires' smaller jets. Pod filters have a weaker pulse at low rpm, but midrange is not affected. Back pressure is a myth. With a proper exhaust, you have just as much low end as with a smaller diameter exhaust, but better flow and more power everywhere else.

Here's the difference-
Open velocity stack on carb- 165 main
Big air filter attached to carb (no airbox)- 148 main
Very small pod filter- 135 main

The horsepower loss is 7 from largest to smallest main setup.
Peak torque is the same for all three, but happens earlier with smaller main setups.

Interesting. Was this done on a Ninja 250 engine? Are you sure the "very small pod filter" wasn't just restricting air flow? What was the main jet with the stock air box, and how did you determine you had the correct jet size for the modded filters - especially if it lost 7 HP?

How is backpressure a myth? Have you ever altered a muffler and noticed a negative change in throttle response? Gaining top-end power but losing mid-range? As you increase the header dia you will lose velocity but gain max flow. That's fine if you want peak power, but it's not going to help cruising MPG. Why do most engines run better with a muffler than just a straight pipe?

Your turn...

If it really reads the wheel itself, why do sprocket changes count at all? If you don't change tire size, wheel rotations over the same distance shouldn't change.

The pickup for the speedo is in the tranny output shaft. Most bikes read off the front wheel and sprocket changes do not change the speedo reading. The CBR speedo "reads off the rear wheel" but not directly off the wheel itself. The output shaft of the trany which drives the front sprocket depends on the rear wheel for information realtive to vehicle motion.

Guess I oculd have been more specific in my description. It works a lot like the speedo in cars. Speedo reading is digital.

regards
Mech

All jetting was on Dynojet dyno with exhaust sniffer.

Stock airbox main was 155.

Small filters DO restrict flow due to pressure change.

Going larger on exhaust only affects response badly if you are already on the large side, and going larger. If you are on the small side to start, you will not loose throttle response even at low revs.

Most people don't want to spend the money on dyno tuning, which is why alot of bikes DO run better with a muffler. It IS all in the jetting to get the best performance out of the mods you make.

Lots of motorcycle intake ports are very large, too large and you can gain big response in reducing the size of the ports, but big carbs, cams and open exhaust make this MORE of a problem, ESP on the bottom end performance.

Combine this with the fact that most motorcycles have poor ignition setups, that are computer controlled, and need to be advanced a good deal to bring bottom end performance to where it should be.

Example, my bike from idle to 3k rpm's fires at 5 degrees before TDC.
Above 3k , it is 31 degrees before TDC.

Now, with E-ZERO and proper jetting, the bottom end response is much better, AND it makes more power up top.

With E10 and proper jetting, below 3k is only usable in the first 3 gears, but only at light throttle in 3rd. Makes less power up top as well.

Now, if I could advance the timing the E10 should work as well as the E0 in power and response.

Honda CBR125i or CBF125i (both chain driven) or maybe even a Honda Innova, using the same engine with an automatic scooter drive.

The 125i should be powerful enough to propel a streamliner beyond 70 mph - the stock chain drive versions will top out around 70 mph.

I found a Ninja 250 on CL this afternoon that was for sale at Fremont Cycle Salvage for a good price and decided to go immediately to check it out. Its a 1999 Ninja 250 that had some cosmetic damage with 23K miles on it but seemed to run strong with a straight frame and forks. I negotiated a price and settled on $799. They had already received 5 calls about it but I was the first person to show up. While I was there another prospective buyer came in looking for the Ninja 250 I had just left a deposit on. whew!!! I will pick it up the bike tomorrow.
I was starting to get a little disappointed that I had missed out on 2 other bikes this past week but I'm glad I stuck to my plans and was able to get this bike well under budget. Attached is a picture of it. I can hardly wait to start working on it.
all the best, Vic

Vic, congratulations. That's a great price for a complete Ninja 250. Please start a build thread so we can follow your progress.

-Garth

Old Mechanic, Thanks for the info on the CBR250R. I'll be selling off the old stock and looking for a salvage CBR. I love the fact the rear section is just bolted on, should make an Alligator mod much easier. I suppose someone will come up with a hack to correct the speedo for gearing changes as well as be able to change some other FI behaviors to maximize mpg, just may have to wait for a while.

What changes have you noticed after the 3000 miles?

Maybe I did not explain it properly. The rear mono shock is almost directly under the back of the fuel tank where the frame is triangulated and probably the strongest part of the frame. The rear portion of the frame is not bolted on. There are two tubes that extend back and support the seats and the rear fender, lights, etc. You could easily cut off the rear tubular section and make a lower seat position, but would probably have to relocate the air filter housing or make a different one. The rear wheel has a small plastic fender that is very close to the tire and moves with the suspension. Since all of the rear axle loads and stresses are directed to the pivot point of the rear suspension and the mono shock, nothing behind those two locations really is important.

Find one with the back damaged or one that was down and you would have the basis for your streamliner.

regards
Mech

Thanks Garth!! I got the bike home and it runs pretty well. The tires are even pretty good on it. I need to get it registered and serviced and then I'll run a tank or 2 as a baseline. I'm thinking I'll change some sprockets first before I start working on my aeromods. Good luck with your search for your project bike ( also to Old Mechanic ).
all the best, Vic

Congrats Vic! It will be interesting to see what your baseline number are.

If you are looking for some Ninja 250 info, check out - Ninja250 Riders Club :: Index

Post up some more shots of it when you can.


Jay

I'm broke right now but thought one of you could use this 1988 kawasaki ninja 250

It is in the Lansing Michigan area.

Good luck
Kirk

Vic, before you rush out and buy sprockets consider going to a smaller chain size from stock.

The 250 Production folks who race EX250s have found that going from the stock size to a 415 or 428 chain and sprocket makes a noticeable (about .5-3/4hp IIRC) change on a Dynojet acceleration-type dyno. Obviously, the difference is not from an actual horsepower increase, but rather that the parts spin up quicker which the Dynojet sees as more power.

So you'd get both a bit better acceleration and a small reduction in weight, some of it unsprung. For the type of use you'll be giving it there shouldn't be significant longevity issues from the smaller chain/sprockets.

cheers,
Michael

Hi Michael, Thanks for the suggestion. I just got my Ninjette titled and will be doing a baseline run. Then I'll start modifying it to achieve optimal fuel economy under "Vetter conditions". Do you have a motorcycle currently?
Merry Xmas , Vic

Yes, but I'm at a current low for the past few decades of about 8-10 of them. :D

I had an EX250 on the street for a bit before I turned it into an AFM 250 Superbike racer (the original plan was to build a custom framed one for the F3 (125 GP) class.

Euro Spares - The EX250 + 125GP = ? article

If you think it would be of any use to you I've got a Specialist II race exhaust system for a Vision (I think you've mentioned having one of those) that was on a friend's racer for 4 or 5 races in the 1990s. It isn't doing me any good sitting in storage and it is yours if you think you want to mess with it.

Any aftermarket exhaust for an EX250 I've seen has generally been 2 into 1s with large headpipes and minimal silencing, so I'd recommend you stick with the stock exhaust to start.

I've always been a racer and fuel economy hasn't been a significant concern (I deal with economy by driving on the street as little as possible) but I am interested in extracting power efficiently and not throwing it away with bad aerodynamics. I've got an FF project among all the vintage dirt bike/roadracers/piles of "there's a bike in there somewhere" stuff. :)

cheers,
Michael

I think the CBR would be very hard to beat. Closed loop fuel injection is essential, so one might as well start with something with all the pieces matched to begin with. Other things being equal, I'd expect a single be slightly more efficient (in BSFC terms) than twin.

I'm expecting Charlie to have a Gator-style streamliner this year.

Low&slow
Alan Smith is running at 6500rpm at 70mph. I thing that with his Aero ninja 250 configuration, both of you could drop the rpm down to 4500rpm at 70mph without getting into any drivability problems. You can always shift down a gear In the face of head winds and hills and if the lower gear is still below 6500rpm then you have a gear for every condition you face. With a tail wind you mite have to stop and drain fuel from the tank just to prove you had the motor on,:eek:;)

Hi Redyaris, Alan is currently running a 15t/39T sprocket combo on his Ninja 250 and he is looking to bump it up some more. My stock Ninja currently turns about 8500 RPM at 75 mph so its definitely an area for improvement. Its nice having a 6 speed tranny and chain drive for a change !

all the best L&S

Three Wheel Race Car

I wonder how this would do at a Vetter Challenge?

Frank , A 3- wheeler won the 2010 Carmel Vetter Challenge but it only got ~89 mpg . It had some type of fuel venting problem during the run and was dumping fuel after the top-off at the start. Fred Hayes had a higher mpg but was placed second because the price of diesel made for a higher cost/mile that determines the winner. Its the same red 3-wheeler that's on the Ecomodder home page and had been sold to a guy in San Luis Obispo. It definitely has potential .

I have both an 09 Ninja 250 and a 2011 Honda CBR250R. As stock bikes, the Honda kills the Ninja on fuel economy. Check Fuelly. I can average 87mpgUS at 65mph on the CBR250R and the best I can get with the Ninja is 66mpgUS. Some of the small 125cc air cooled Hondas from India can get 130mpg but only have a top speed of 65mph whereas the CBR250R is a dream to ride all day long in the rain at 90mph. It is a real bike, is available with ABS and only costs $4000 brand new with great factory financing.
.
Gas Mileage CBR250r - Honda CBR250R Forum : Honda CBR 250 Forums
.
Honda CBR250R MPG Reports | Fuelly

Good to see that your CBR250 log grew longer, experience is accumulating :)

What kind of temps are there in this stage of year where you live?
Teresa's FE suffered the frost quite a bit, now I can only dream of 80+ mpg...

edit. I see - so the CBR can do 80mpg at freeze point. Very nice!

My average has dropped from 87 mpgUS to 81 with the addition of the the grip muffs to keep my fingers warm from cold temps that are just above freezing. I don't ride if it has been below freezing so I am mostly done until March.

Are you sure the grip muffs are to blame and not the colder temps with the winter blend of fuel, thicker grease and oil, etc.? A friend and I have nearly identical F650 GS dakars. She has easy access to 100% gas, I throw in whatever fuel is available = up to 10% ethanol. When she has pure gas and I have ethonol blend we see an 8-10% difference in FE. Obviously the 100% gas getting the beter mpg.

For a Vetter challenge bike, I have liked the Ninja 250 for years because it is available, cheap. I started with a CB250 while my girl friend rode a rebel 250 as the control, but I found, like Alan Smith, the air cooled motor and 5 speed would be going down the wrong path. Suzuki TU250 fuel injected might be good, but if I see a CBR250R, dropped but not bent for cheap, I would have to scoop one up.

The Ninja250 is a great pocket canyon racer for the money but I actually see it as a poor bike to start with for hypermiling. The only reason they are so popular on ecomodders is the cheap price and availability. And it is one of the few bikes sold in the US with less than 600cc's so there aren't many choices. It is a super sport bike with peaky cams. If someone made fuel mileage cams for it and you installed the dual channel, programmable, wide band fuel injection kit from the group buy at Ninjette.org it would be much better. 70mpg stock versus 85 for the CBR250R is already making my point. The Ninja is far from the best choice from a hypermiling competition stand point. The best hypermiling motorcycle that can be ridden on real hiways as a daily driver is the CBR125R. A +1 on the front sprocket is all that is needed to have a 90mpg commuter that can top out at 75mph. Still a real bike for a solo rider with gorgeous, functional bodywork. Sadly, not sold in the US. I am going to import one eventually. But, air cooled will beat water cooled. Not for longevity but it will be more fuel efficient. Water pumps waste power. Any of the air cooled 125cc cheapos from India get way over 120mpg right out of the box but can't reach beyond 60mph. Until you change gearing and add a full streamliner fairing. Used bikes in India would be in the $6-800 range. Not anything to go touring on, like either of the 250"s are, but a great start for a competition vehicle.
.
CB Shine winner's choice
.