Quote:
Originally Posted by greenaero
As the others have correctly stated your goals will generally be in conflict with each other. The only ways to get better fuel economy ( FE)while not sacrificing acceleration and top speed would be through 1) improving engine efficiency ( difficult, complicated and expensive), 2) reducing rolling resistance ( bearings, tires, chain, brakes) , 3) reducing aerodynamic drag( the biggest mechanical factor ) and 4)using fuel-efficient riding techniques.
1)Advancing the ignition timing may give a small gain in FE at low speeds but would cause detonation and pre-ignition problems at high speeds. Unless you can have easily adjustable engine timing it's a dead end. Running the lowest viscosity synthetic oils that are safe for the moto or any other changes that reduce engine friction would work. Modifying camshft timing and valve spring resistances would work but only at one end of the spectrum.
2) Run high tire pressures, I run mine at maximum rated sidewall pressure. Radial tires would be better if we could get them in our tire sizes. Keep your chain perfectly adjustted and lubed. NOn-O-ring chains supposed offer less resistance. Minimize disk brake drag. Ceramic wheel bearings offer less rolling resistance but are more fragile than conventional wheel bearings.
3) Reducing aerodynamic drag offers you some big gains in FE without reducing sport riding potential. The more complete your streamlining is , the bigger the gain. You would also be limiting your gains if you don't use taller gearing to fully take advantage of the reduced air drag. For your purposes I would suggest an aero windscreen and a removable aerotrunk like I run on my
Silveraero project moto. I average around 90 mpg with it and a best tankfill of 111 mpg. It does have tall gearing ( 15/37 ), but you still would see a significant improvement in FE.
4) Using optimal riding techniques will allow you to get the best FE out of any moto. For the best FE it's all about using every drop of fuel to go as far as is possible. Limit stopping, braking and idling as much as posssible, use moderate acceleration to your target cruising speed and maintain it with the smallest throttle opening, if you see a slow down or stop coming up get off the the throttle and coast as much as possible. Air drag increases with speed by the cube so that if you double your speed you need 8 (2x2x2) times the power to do it. The most efficient crusing speed is 45 to 55 mph.
@ Electronic M , what you are after is not impossible , just challenging. Compromise is doable but for me its more satisfying to go all out in one direction or the other. Early on in my riding I loved speed and racing but found I lacked the resource$ and motivation to keep pursuing it. Racing is extremely competitive and already loaded with talented, exceptional riders. I chose a different, less traveled path and have found great success and satisfaction with it. Good luck with your quest and keep us posted with your efforts. |
Thanks for your advices.
1) I am planning to adjust a/f mixture and ignition timing to gain more power and better fe by leaning the mixture out at cruise ( I am sure it's not optimal from the factory) and I'll be able to push it to its limit with a closed loop ego control, I was able to improve fe by more than 20% on my bigger bike and I didn't even come close to pushing a/f mixture to a 16.5 ratio. With a better engine control I am hoping to get the best bang for the buck without going into the engine. I will also run 10w30 synthetic after I get some data from a regular oil, if there is an improvement, I will stick to it.
2) I will keep my tire pressure bellow maximum for safety reasons, I am sure I'll be able to have better gains going from 30 psi to 40psi than 40psi to 50psi, I will also monitor tire temperature while I am at it. I have also ran non o ring chain before with great success, I was able to shave a .1second with it at the track, but for street they're not very dirt friendly, so I'll just stick to o ring type of chain, even though there are gains to be had. Ceramic bearings are waaaaaaaaaaaaay too expensive and don't offer much of a gain imo.
3) I will keep aero mods to the minimum, at least at first. There are good gains to be had, especially at speeds over 45mph, but most of my commute is around 45mph so I'll keep that for the future mods after everything is done. Gearing will be one of the first mods, it's cheap, and offer gains and easily put back to stock if i decide to bracket race the bike.............don't ask me why hahahahaha.
4)Riding technique is where most gains are at imo. I'll put a mpg or mph gauge on the bike and monitor where its the most efficient rpm and throttle angle and will adjust my riding there.
Racing is a lot of fun, but does cost a lot of money, especially if you want to stay at the very top lol.