Thread: Wr250x
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Old 02-16-2009, 05:40 PM   #5 (permalink)
EcoModding Lurker
Join Date: Feb 2009
Location: Texas
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Originally Posted by MetroMPG View Post
First aero, then gearing (since you won't need the same power to cruise at speed).

[...]I take it you've seen some of the other project bike threads here (like the electric aero Ninja 250 and the fairing/gearing project going on with the Suzuki Bergman).

Welcome to EcoModder.
Thanks, MetroMPG. Yes, I have looked at those two projects. I think I will trade leaning forward to get ultimate mpg instead of a tall tail structure ala Craig Vetter. I worry about crosswinds. I also worry about aero stability, more of an issue for two wheeled vehicles. I'd rather have the drag back and the CG forward, like an arrow or a rocket. That doesn't mean it can't be cleaned up back there, though. That's the best real storage space on a motorcycle, so I hope to use behind the legs and back for compact practical storage that sort of "fills the hole in the air".

Originally Posted by janvos39 View Post
When you start with aerodynamic mod's you will find out that at higher speeds more power is left to do acceleration. This means that you can use an higher gearing and lower the rev's and fuel consumption. A manual six gearbox is ideal for that. An other thing to address is the engine temperature. I have problems on my Suzuki Burgman to get the temperature in the cooling water after reducing the air resistance. I already reduced the air to the radiator with 50%.
I am very interested in your project.
Are there any "rules of thumb" for best gearing for cruising mpg? I think I read here that somewhere below the max torque rpm is best, but where? As far down in rpm as the engine will still maintain speed?

Do you mean your Burgman engine has trouble reaching (or staying in) normal operating temperature range? The WR250X cooling system has a thermostat, so flow through the radiator is (mostly) shut off if the engine is cool.

Synthetic: Yes, I plan to move to the Yamaha-approved synthetic.
Foam air filter: check (stock is foam)
Lower handlebars: Good idea. So far I have shortened them by 2" (from 30.5" to 28.5") to reduce frontal area a bit. I will have to see what it feels like with lower bars.
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