Low & Slow's Ninja 250 project

[bschloop]

efficient fairings don't just need to be "cool" to go mainstream. They need to be cost effective. people don't typically spend $2000 on a fairing. I can even find fairings specifically meant for racing at $700 for a full set. If you could buy a fairing and matching "trunk" for $500, I could see lots of people buying them for their scooters and small bikes. especially in MI where it's cold for so much of the year. I already see people out on bikes wearing full snowmobile gear when it's 40 deg out.

[Kincurd]

To hell with how cool others think you look. I mean, I had an acquaintance who was in a coma after a motorcycle accident. He made a full recovery and started wearing a full face helmet on his Harley. Out here where there's no helmet law, he caught a lot of cat calls for riding a Harley with a full-face.

Although, I'm all for making your aerodynamics smooth and good looking (oh, there it is again. Good looking to us ecomodders at least) . Rivets and dents, and uneven surface area aren't as aerodynamic anyway (better than nothing though, obviously.

[jkv357]

Originally Posted by Kincurd

I'm trying to figure out how slow the acceleration was though. I wonder if it took Matsu 5 minutes to get to 55mph or something crazy.

I wouldn't think that would work to get 477 MPG. For that, coasting had to be a major factor IMO.

In addition to a small, aero shape, Matsu had a neutral available from top gear so he could coast at cruising speeds with as little resistance as possible. Because accelerating is the opposite of coasting, I would expect he would reduce the time spent accelerating to an absolute minimum by running at wide-open throttle during acceleration then using the momentum, aero shape, and trans in neutral to coast as long as possible - maximum P&G.

It does seem counter-intuitive to accelerate at WOT during a mileage competition, but because the engine is so small, and the pumping losses are minimal at WOT, it may be the most efficient way to use fuel now in order to be able to coast more later.

Here's an interview with Matsu, but it doesn't give any specific info about the techniques he used - 1985 Matsu talks

Just a theory - what do you think?


Jay

[sendler]

Originally Posted by jkv357

Here's an interview with Matsu

Funny one liners. Too bad the bike didn't end up in a museum.

[Kincurd]

Originally Posted by jkv357

I wouldn't think that would work to get 477 MPG. For that, coasting had to be a major factor IMO.

In addition to a small, aero shape, Matsu had a neutral available from top gear so he could coast at cruising speeds with as little resistance as possible. Because accelerating is the opposite of coasting, I would expect he would reduce the time spent accelerating to an absolute minimum by running at wide-open throttle during acceleration then using the momentum, aero shape, and trans in neutral to coast as long as possible - maximum P&G.

It does seem counter-intuitive to accelerate at WOT during a mileage competition, but because the engine is so small, and the pumping losses are minimal at WOT, it may be the most efficient way to use fuel now in order to be able to coast more later.

Here's an interview with Matsu, but it doesn't give any specific info about the techniques he used - 1985 Matsu talks

Just a theory - what do you think?


Jay

Yeah, I had read that interview earlier. It's really a shame they crushed the spud.

All I can say is I hope you're right. It's pulse and glide at the highest level.

I guess the initial acceleration from a complete stop had to only be done at the beginning and he could take his sweet time if he wanted, but over 200 miles (if I remember correctly) it's a drop in the bucket.

So while he could give himself really slow initial acceleration, it wouldn't be necessary. You could still have small lower gears to merge onto that highway and enjoy the fuel efficiency once you've got going.

No neutral is the biggest issue I have with my scooter, but you can't find manual scooters in the US. They still make 'em like that new in Asia (where neutral is at the bottom; below first gear)

Having neutral on the top is kind of the cherry on top, but as long as you can pull in the clutch, you're good; wears out your hand quicker though.

[jkv357]

Originally Posted by Kincurd

Having neutral on the top is kind of the cherry on top, but as long as you can pull in the clutch, you're good; wears out your hand quicker though.

There will be a significant difference between coasting with the clutch pulled in and coasting in neutral. With the clutch pulled in the trans is still being spun by the rear wheel while coasting, creating a lot more drag than completely disengaging the transmission by shifting it into neutral.


Jay

[Kincurd]

Originally Posted by jkv357

There will be a significant difference between coasting with the clutch pulled in and coasting in neutral. With the clutch pulled in the trans is still being spun by the rear wheel while coasting, creating a lot more drag than completely disengaging the transmission by shifting it into neutral.


Jay

Ah okay. Thanks. I guess it gives me more reason to eventually tackle the bigger project of a transmission overhaul.

By the way, I heard back from Craig (friend emailed him awhile ago), and he confirmed the old 1980s streamliners accelerated far too slowly, and that's a big reason those designs didn't have any real affect on motorcycles today.

(Ps. this thread reminded to check my email and I should have done that before I posted.)

[Grant-53]

Years ago BMW figured out that for their cars accelerating at 75% throttle was optimum for economy.

[Kincurd]

Originally Posted by Grant-53

Years ago BMW figured out that for their cars accelerating at 75% throttle was optimum for economy.

Knowing that sweet spot would be useful for making a gas pedal-block.

BMW also makes great bikes. I will have one of their bikes eventually.

[Grant-53]

My late father-in-law, Ray Terwilliger, rode BMW motorcycles for years. His last long road trip was to ride his restored 1955 250cc BMW to Redmond, OR from Eden, NY (Buffalo area) to take first place as Best Working Vintage 2010. See pg 80 of Oct. 2010 On The Level magazine.

If you know the RPM of the max. torque of the engine, use that as a starting point for shifting. Check throttle plate position and then set some resistance you can feel behind the gas pedal. This could be an extra return spring or a tennis ball on the firewall. You want to avoid anything that will cause the throttle or linkage to get stuck open.