101.5 MPG on my 2003 Ninja 250!!!

[koihoshi]

Originally Posted by theycallmeebryan

Yes, on the first post i explained that the only modifications to my bike are a 15T front sprocket, 39tooth rear sprocket, and Kenda Tires (touring tires) that are slightly taller than the stock dunlops.

Apologies, not sure how I missed that, I am sorry.

[koihoshi]

Originally Posted by The Atomic Ass

Sport Demons have about the same grip as MT75's in my experience, but phenomenally longer life and lower straight-line drag. Plus they're taller, so you drop another ~500 RPM.

This is true on both accounts.

[cvetter]

I am happy to find real results for the KZ250. Thank you.
My testing is a little different: I assume that bikes are likely to burn more fuel the faster we go. Therefore, I put a lot of faith in the 125 miles between Salinas and San Luis Obispo, CA. on Highway 101. In the summer time, anyway, heading south at 11 am, we buck a 30+ mph headwind. Departing SLO at 6 pm, the winds have reversed, turning into a headwind, becoming a ferocious 40+ mph by King City. I admit this is extreme. but id does represent real riding in my area.
This extreme wind is caused by the temp differential between the cool ocean and the hot interior. The Salinas Valley is a funnel.

The experience as reported by contestants in the Craig Vetter Fuel Economy Contests of the 1980s was to leave the carbs and jetting alone. Some reported improvements with different exhausts, tho. I never understood why since any "improvement" would likely be to produce more power. A KZ250 does not need more power, does it?

The simple solution seemed to be"Streamline it and gear it up"

I can't wait to see what happens with your KZ as you streamline it. Everything should improve.

[thatguitarguy]

That's all good to know because my concerns with more streamlining have to do with how the bike behaves in the windy conditions you are talking about. I like the way the front of my BMW was designed, but I would like to change the stern with a streamlined rear fairing with storage for touring.

As to cold weather riding, I've done a lot of that here in the mountains. I don't ride in the winter because the appearance of ice on the road can happen at any time, but the temps that many of you see in the winter, I see pre-dawn and post-dusk here most of the summer.

My bike is larger, and has a bigger alternator being a retired patrol bike, and needing that capacity for running lights and radios, but the heated grips have saved me a lot of discomfort in cold riding conditions. I used to think that such a thing was frivolous, but now that I have it I wouldn't want to be without it. I ski a lot, and have many ski gloves, but gloves that would be warm enough without the heated grips, are uncomfortably bulky between my palms and the grips. I like to feel the bike through my hands.

[The Atomic Ass]

Originally Posted by Christ

Do you have a heated seat pad? That's something I was thinking about looking into for the Honda, even if I have to get a slightly bigger battery. I'll extend the riding season a bit that way.

Me? No. I've got a jacket liner and gloves.

With the greater wind protection of the Burgman, I was able to ride in -7F last year.

[The Atomic Ass]

Originally Posted by Christ

If the mileage comes out to less than 50, I'd be better off driving the Van or something, even at 25 MPG, for the comfort factor.

You will NOT hit 50mpg, unless you have some severe mechanical problems, or drive too fast.

[Christ]

Originally Posted by The Atomic Ass

You will NOT hit 50mpg, unless you have some severe mechanical problems, or drive too fast.

If it keeps giving me problems, I'm going to part it out and see how fast I can hit 50 DOLLARS. Damn bike. I'd really rather have a sport bike or a scoot, but this one was cheap and was in decent condition with low miles.

[Christ]

theycallmebryan -

I've been half wondering about something you mentioned earlier in this thread (maybe in another one) about the fuel economy of the '08+ Ninja 250's:

The newest models are touting less FE and more top-end power than the earlier models, right? They also have radically redesigned body work, and are slightly heavier...

What I'm getting at: What if the FE numbers aren't necessarily lower b/c of the new DOHC FI engine? What if it's aero and added weight that's taking those extra few MPG off the ticker?

Looking at pics of the old gen and the new gen, I can actually see how this might be possible... things like a front fairing that necessarily dumps airflow right into the rider's chest at an upward angle are indicative of styling leaning more toward "Oh, look, it's a fast bike" than "Oh, look, it's aero-efficient".

Also, it seems like the newer gen has more frontal area than the older gens do, all things considered, but that could be perceptive from pictures being inconsistent in size and angle.

From this image:
it's rather apparent that your feet and hands are sticking out there, as it were. Of course, this was also the case on the older gen, as far as I can tell. Maybe a few extra ounces of plastic could make up a good bit of lost MPG due to aero at highway speeds? Even just popping out the sides of the front fairing more, so that the high-speed flow is pushed slightly further outward as it detaches from the plastic, so it doesn't run into your hands on the bars.

Maybe closing the upper part of the doghouse to airflow and adding to the body fairings down onto the front fender's nose would add to the MPG numbers, as well?

In either gen's case, those turn signals should be flush mount, and the mirrors are... wow.

And lastly, why don't we see bikes in wind tunnels?

19 total images of the '08+ Ninja 250R can be found here!

[Grant-53]

The newer Ninjas went to a larger sprocket adding just one more tooth and tuned for more mid-range torque. As for motorcycles in wind tunnels check out "Sport Rider" magazine for their tests on a couple liter bikes in a wind tunnel a few years ago. The biggest gains are in cleaning up the air flow behind the rider. A tail box for hauling gear should be as wide as the rider and shoulder high. Angle back the sides about 10 degrees and the length should be around 24-30" inches to keep the weight forward. Add truck cab lights for turn signals and running lights. Use auto racing style mirrors on 2" sheet metal brackets about 6" out from the main fairing.

[theycallmeebryan]

Yeh grant, i plan on starting with a tail first (that will include cargo bays) and try to clean up the rear of the bike.