Low & Slow's Ninja 250 project

[Bruce]

Originally Posted by low&slow

Thanks Bruce.
The Ninja 250's are a good starting point but IMHO not the ultimate. The Ninja's are reasonably efficient , plentiful and can be purchased at a good price with some searching and bargaining. If I were starting from scratch I would look for a cosmetically damaged Honda CBR250. They are significantly better than the Ninja 250 for fuel efficiency with their single cylinder, FI and better low end torque. Look at what Sendler has done with his. HIs impressive performance has been achived currently without radical streamlining like I have done on my Ninja.
I would agree that for a low budget hypermiling project bike the Ninja 250 is a winner.

Good point. I should have qualified that I was considering my budget and the "plentiful and cheap" aspect.

[beatr911]

Vic,
Good report, and congratulations! So many think that a 100mpg single person vehicle is a stretch and you all are proving it's not that far away.

One important point you have made with your build is that it doesn't take rocket science, a big bank roll or even hundreds of hours of talented fabrication work to produce a 100mpg machine. Careful vehicle selection, basic bike set-up knowledge and surplus materials can net you very good numbers. And what is your total investment, $1000?

Again, nice work Vic. You have just pushed motorcycling a little farther ahead to the future.

A huge thanks to Craig Vetter in setting the stage and the height of the Limbo bar for the outstanding performances of this last event. It just keeps getting better and better.

[Grant-53]

East of the Mississippi 75-80 mph is considered fast. Out west speeds are higher partly because of the geography. There are a few places outside Buffalo where people have been clocked at 135-140 mph on radar but you have to be very brave or foolish to try it.

[jkv357]

Originally Posted by low&slow

(SNIP) The ride was fun and the pace was fast; it was the fastest pace I've ridden the Ninja at with speeds up to 85 mph and lots of hard acceleration to keep up and prevent being passed by Craig.(SNIP)

I just don't get Craig's reasoning on that. Is it an efficiency competition or a race? Why is there a need to run 85? Why would you need to break the law to compete? Is that the "real world"? I wonder how many potential competitors are turned away because of it.

I can understand the grocery carrying requirement I guess (maybe not 4 full bags though), but the first thing you'd do if you wanted to use less fuel in the real world is just slow down - at least to the speed limit.

Congrats on another good showing!


Jay

[Frank Lee]

I hear ya. Anything over 59 mph on my turf exposes me to a speeding ticket. I don't like speeding tickets.

[FXSTi]

Vic,

I just had a thought, and don't remember reading about it in this thread (sorry I am in a hurry and have not re-read).

Have you lowered the bike? I spotted a couple lowering kits while looking for one for my wife's 500 ninja.

[low&slow]

Thanks Garth, Stan, Jay, Grant & Frank!
Craig's mission is to push the limits on motorcycle design so that they are more efficient, useful. practical. comfortable and still fun to ride. He understands that slower speeds allow higher FE but as a sporting rider and former racer he wants the ability to go fast also. Just as in real traffic we wouldn't want to hold up the flow of traffic, Craig doesn't want his Challlengers holding up the pace on a sporting motorcycle ride. The pace was fast and the CHP group leaders provided some opportunities for riders to air out their fast bikes. At one point the CHP passed the group to get ahead o the group to control traffic at key intersections at least 100mph. The 2 laps around the racetrack were also very fast. Craig intentionally seeks out these diffiult conditions to test us to the maximum. That Alan and Fred could break 100 mpg is incredidble and that the other Challengers still could produce relatively high FE gives credence to Craig's approach. A hypermiler will never produce his best FE during a Vetter Challenge.

During and after the ride, many sporting riders commented on our ability to stay with the pace despite riding the smallest displacement and the physically largest machines. Part of Craig's vision is overcome the prejudice of the traditional motorcyclist and we definitely changed some perceptions that day.

[Grant-53]

The trick for the Ninja 250cc will be getting more torque at 4000 to 6000 rpms. The twin is a short stroke design that gets its power from high revs. The Honda singles get more torque below 7000 rpms than the twins.
This creativity will help get more people riding "entry level" motorcycles and attract people such as myself who would never spend the money on an intimidating literbike.

[beatr911]

Stock, the Ninja 250 does it's best at high RPM. Bore x stroke has something to do with it but cam timing and profile contribute just as much. Has anyone looked into altering cams, intake and exhaust to increase torque in the 4-6K rpm area?

[jkv357]

Agreed - a custom-ground cam that drops the power peak could do wonders for the Ninja. The latest 250 Ninja engine is slightly detuned from previous models, and power drops off earlier, but it didn't really seem to pick-up much in the midrange judging from the dyno charts I've seen.

A set of cams that were designed for peak torque in the midrange instead of peak HP on top should get you a lot closer to a "sweet spot" when cruising with full aero aids.


Jay