Low & Slow's Ninja 250 project

Discussion in 'Street and Performance Bikes' started by low&slow, Jan 1, 2012.

  1. low&slow

    low&slow Well-Known Member

    After the recent Las Vegas to Barstow Vetter Challenge I have thought a lot about my future participation in these real-world fuel economy contests. While I'm pleased to have improved a 40mpg bike into a 60mpg+ machine I have to recognize the inherent disadvantages my Yamaha Vision ( 550cc shaft-drive bike) presents versus the 250cc gas bikes and the diesel bikes that have been the previous Challenge winners ( 134 mpg to ~ 157 mpg). I decided to start looking for a used 250cc bike to modify for future fuel economy runs.
    After about 2 weeks of searching I found a 1999 Kawasaki Ninja 250 in good running condition for a good price and well under my project budget. It was a salvaged bike and so I had to have it inspected and the engine and frame #s verified to get it titled and registered for street usage.
    I adjusted the valve clearances, sparkplug gap, cleaned and re-oiled the air filter and changed the oil and filter. I topped off the tank and rode it around running errands for a few days before doing my first official mpg calculation: 65 mpg.
    Today I rode with Alan Smith( Ninja 250 streamliner ) and another stock 2008 Ninja 250 as well as a Triumph 1100 and a BMW 1200. We topped off our tanks at the start of ride and refueled at the end of the ride 126.7 miles later. The ride was at a spirited pace on twisty backroads on a cold day with with about 15 freeway miles on the way back. Alan got 89.47 mpg, the 2008 ninja got 62.1 mpg and I got 72.8 mpg. I was pleased with how the bike runs and how well it handles. It was interesting to compare the 2 stock ninjas with Alan's to see how effective his modifications are.
    Now that I have my baseline I'm ready to start my modications. I'll start with a larger countershaft sprocket ( 15 tooth vs 14) and larger windscreen. I'm pleased to already have beaten my best tankfill on my Vision 550cc ( 66.8 mpg) . I'll try to keep posting on my progress.
    Happy New Year , L&S
  2. msirach

    msirach Well-Known Member

    Congrats on the new bike. You will be happy with the gains you will get with the 250.
  3. phoebeisis

    phoebeisis Well-Known Member

    The countershaft will certainly work-it will be interesting to see just what the taller windscreen does,
    Are you going to add mods one at a time- measure-so you can tell what helps-what doesn't?

    I loved that Vision- it was a very modern bike in its day. I had a choce- back when- of it or the 550 Seca-Seca was lighter-went with it. I'll have to see if I have a brochure giving EPA mpg of the two-.
    There is a tiny chance you can parts engineer different gearing for the Vision.You might find a rear wheel with different gearing that will mesh with your Visions shaft gearing.I've never heard of it being done- but then I haven't really looked for it.
    The bigger 550 twin would really require low gearing to match the 250 Ninja of course.The Ninja was a fairly high performance bike-it might have a fairly peaky cam-maybe there was a less peaky version-cruiser version- of that 250??
    No doubt the fellow with the Ninja will have already covered these bases!

    Keep us posted looks like fun!
  4. low&slow

    low&slow Well-Known Member

    Thanks for the support! I don't have the patience to test modification one at a time but will try do some separation and evaluation as I progress.
    Charlie, The Vision is a great bike and I'll definitely keep mine. Kawasaki did make a cruiser version ( 250 Eliminator ) but they are hard to find.

    Report #2 After getting the baseline for the Ninjette ( 72.8mpg ) I could hardly wait til I started doing some mods. I haven't bought sprockets yet so I decided to start modding the front end of the bike. I removed the windscreen and front fender . I made a longer, taller windscreen out of coroplast and mounted it on the stack faring. I made a fully faired front fender out of sheet metal, coroplast and some outdoor sign stock. Since I'm going with a Vetter tail, I just bungeed on a plastic trash receptacle behind me until I start building the tail. I need to do another run see how it works. more to follow.
    all the best, L&S
  5. FXSTi

    FXSTi Well-Known Member

    Pictures, I need pictures.

  6. phoebeisis

    phoebeisis Well-Known Member

    Very nice- yes pictures!!


    PS Did anyone see my Saints beat Detroit like a red headed stepchild!!
  7. low&slow

    low&slow Well-Known Member

    Charlie, The Saints were awesome! Their game with the 48ers should be a another good one.

    I posted a pictures in the gallery . I rode it yesterday and today and it handled the winds very well. I ordered a larger countershaft sprocket and will test that after I install it. I also replaced the stack seat with one I made for a lower seat height.
  8. phoebeisis

    phoebeisis Well-Known Member

    Normally I'm not optimistic about the Saints(old so I remember the "old" Saints even though these guys play nothing like the old Saints).
    However I like our chances against the 49ers- figure we are a slight favorite.

    No problems in side winds?
    I remember readinf-way back when before my time- motorcycle racing banned "dust bin fairings" because of handling problems in side winds.You fairing is nothing like those- but the tail section sure is big.

    Neat looking
  9. low&slow

    low&slow Well-Known Member

    I filled up today and got 59.3 mpg. Disappointing. I may do one more tankfill before I install my 15T/33T sprocket combo so I can better evaluate the aero mods. The taller gearing should make a differenece.

    CHarlie, too bad about the Saints. It was a great game though

    alll the best, L&S
  10. phoebeisis

    phoebeisis Well-Known Member

    The sprocket will help more than aero mods I think.
    Aero mods are so hard to do via eyeball.
    Stuff that "looks good" might not actually be very good.

    Yes the Saint's game was a heartbreaker.
    So maybe turnovers- but we still should have won.
    Ahead with 1:22-they go 80 yards.
    We have a no defense defense-so it wasn't a complete surprise.

    In 2009 our defense gave up lots of yards- but we had takeaways-Darren Sharper was the best defensive player we EVER HAD.
  11. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Charlie, I think that aero-mods would help a motorcycle more than just about anything. But I'm sure it's not easy to do them or live with the results. Does Vetter ride his aero-modified Helix every day ? I dunno. But I have a dream about a recumbent aero-liner powered by a Honda CBR250 fuel-injected single. You would give up some of the low-speed maneuverability of a conventional (short-wheelbase) bike , but get weather protection that would extend a short riding season (Chicago) by several months at least.
    But you'd need to be braver than Basjoos to do it.
  12. phoebeisis

    phoebeisis Well-Known Member

    No question motorcycles with cd's of what- .6 or so- have lots of aero potential
    but actually getting better CD's via eyeball- kinda tough trial and error.
    Now doing a copy of whatever Vetter is actually doing-should work great- but like you say- is it practical-in side winds etc.

    Bicycles - best way is to go recumbent- but most folks don't like bents(don't have the nice upright view of the cars that are about to centerpunch you)

    Yeah plenty of aero potential-but tough to live with it.
    A sprocket-cheap easy-and 10% drop rpms should give 3-5% better FE(pure guess)
  13. low&slow

    low&slow Well-Known Member

    The bike is hard to fill consistently , I think I must have had a short fill on the previous fillup and I had lots of shorter runs rather than the single long run of the last 72mpg tankfill. The next fill should fill show the changes better over several tanks. The gearing shoiuld help a lot.

    Charlie ,The Saints looked like they had cooked the 49ers' goose but their defense let them off the hook. Maybe next year with some defensive improvements.
    all the best L&S
  14. low&slow

    low&slow Well-Known Member

    Previously: After getting a baseline and installing some initial aero mods I was anxious to see how my Ninja 250 was performing.I filled the tank and the result was 59.3 mpg ( after previous tankfills of 65mpg and 70 mpg). Disappointing. I decided to do one more fillup to get a better perspective on the aero mods before installing the taller gearing . The Ninja is a bit harder to get consistent fills and I may have short-filled previously. Also this tank had lots of mixed riding over several days vs the single run of my previous best.

    I did another test run today and the results are.... 74.6 mpg. So at least some improvement over the stock Ninja configuration with the aero mods. I'm going to install taller gearing and will go with a 15T front/ 41T rear combo for now. After some discussion with Alan Smith and I decided to try the 41T rear first before going with the extremely tall 33t sprocket that GreenJoe had sent me. I feel very optimistic as the Ninja is very short-geared, easily pulling 6 th gear at 35 mph.

    After I returned home this afternoon I removed my 14T countershaft sprocket and 45T rear sprocket replacing them with a 15T and 41T combination. They are now installed and I 'm glad I followed Alan's advice to go with the 41T as I'm pretty close to maxing out my adjustment for the stock chain. I just need to finish adjusting the chain and torquing up the rear axle before its ready for its next ride.

    Edwin, Craig Vetter rides his streamlined Helix all the time, his goal is to design motorcycles that are fast enough, efficient , be able to carry a significant load , are comfortable and would be the first choice of the owner for transportation. I rode with him and Alan Smith in the Las Vegas to Barstow Challenge during pretty strong crosswinds and his Helix and Alan's Vetter-tailed 250 Ninja handled fine. My Vision streamliner struggled at times and I had to let off the throttle several times to stay in my lane. My current streamlining on my Ninja 250 is much better and handles fine in strong winds. We have fairly frequent windy conditions here in Livermore and have many large windfarms in the area. After riding streamlined bikes for the past 6 months I would find it hard to go back to a naked bike or one with a small windscreen. The protection from the wind and the greater ease of passing through the air are addictive.
    best wishes, L&S
  15. phoebeisis

    phoebeisis Well-Known Member

    74mpg- wow- it is tough to consistently fill those little 4 gallon(guess) tanks.

    If in stock form it turns 6000 rpms at 60mph- you'll turn about 5100 or so now.
    Maybe it isn't geared that short??
    In any case 17% drop in rpms-sould be good for 5-10% better FE-3 mpg or better
    If it would actually get 75+mpg on the hy-that would be pretty good.
    Last edited: Jan 19, 2012
  16. low&slow

    low&slow Well-Known Member

    The bike turns about 7500 rpm at 60 mph so the new 15/41 combo should put it at around 6000 rpm at 60 mph. Much better . I hope to break 80 MPg with it. We'll see.
  17. basjoos

    basjoos Well-Known Member

    The drop in rpm will help the engine to take better advantage of the reduction of wind load resulting from the aero mods and should also help to extend the engine life.
  18. low&slow

    low&slow Well-Known Member

    Hi Basjoos, Yes, it should. Thanks for your input, I am a huge fan of your work!

    I rode the bike today with the 15/41 gearing ( vs 14/45 stock ) today and it is much improved. I can confirm that the rpms are now down to ~6000 at 60 rpm. The bike still accelerates very well and actually it can handle even taller gearing. I'm using Alan Smith's spare rear sprocket right now and he also has a 39 tooth rear he offered to let me use. He is currently running a 37 tooth rear right now. I also have a 33 tooth rear that another motorcycle hypermiler sent me ( thanks GreenJoe) . I'll run this setup for a bit and test it. I'll post the results shiortly.
    all the best L&S
  19. phoebeisis

    phoebeisis Well-Known Member

    Wow-7500 at 60 mph-forgotten how short they geared bikes.
    What sort of hy speeds do you ride?
  20. low&slow

    low&slow Well-Known Member

    Hi Charlie, It rained today so I gave the Ninja the day off. I ride the speed limit so 65-70mph on the freeways. My goal is over 100 mpg under Vetter Challenge conditions which are at a "spirited" pace and riders are eliminated if they are passed by the trailing vehicle
    (usually Craig Vetter) during the events.
    all the best, L&S

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