101.5 MPG on my 2003 Ninja 250!!! - Page 10 - Fuel Economy, Hypermiling, EcoModding News and Forum

3-Wheeler · 08-19-2009, 02:37 PM

Bryan,

I read in one of your recent posts, that your tear-drop bodywork will be about 10 feet long.

Take a very close look at the body shapes and *lengths* from the Craig Vetter High Mileage Contest from bygone years. Several of those streamliners did indeed crash when piloted on the very twisty and windy California coast during several competitions.

One tipover was the now infamous Honda streamliner piloted by stunt rider Deby Evans, a very skilled rider. The high winds caught her off-guard, and down she went. The body-work was pretty beat up and she retired early and did not finish the event. The streamliner had full body work including a large canopy to cover the rider and allow good sight, similar to your idea. Unfortunately, this design also suffers from a large susceptibility to sidewinds.

Charlies entry on the other hand, with his exposed back has some very obvious benefits, including good air separation from his body during large side wind forces. He also has the option of sitting up slightly if the side wind increases, which effectively decouples the lift generated by high winds, making for a safer and less tip prone ride. Obviously, keeping the overall length shorter also helps.

You may want to rethink utilizing the more efficient, but more unstable full canopy design. On the other hand, if you were set on building a full canopy machine, then you may want to think about lowering the whole CG of vehicle and adding a third wheel, thus making a Class II motorcycle as I am in works of building.

Just some food for thought, Jim.

Christ · 08-19-2009, 03:15 PM

Also, refer to "center of pressure" as well as "center of gravity". Both are relevant when considering motorcycle aerodynamics, as I understand it.

dcb · 08-19-2009, 03:31 PM

Another idea, it might make sense if the tail or part of it, were hinged/spring loaded,

scenario, riding along, doo da doo, side wind comes, deflects tail, increases camber on windward side, generates force to counteract tipping.

Or it is totally baked idea.

HUM727 · 08-22-2009, 06:24 PM

not sure if someone replied yet but the reason ur bike was pinging is cause that gas should not be in your bike, all bikes that i know of, and my sister has that bike, run on premium gas... it may cost 20 cents more butto use 87 u loose fuel economy and performance as well as risk damaging the engine.. figured i share some info on the small amount i know. u might read somewhere that it can take 87 or should.. from my experience that is nothing but bad news

if it wasn't the gas .. the only other reason it would be pinging is sometimes the engine is cold

premium is also much cleaner and on a carburated bike.. that means taking care of the bike much less, cleaning the jets less, and make the spark plugs and valves last just that little bit longer

theycallmeebryan · 08-22-2009, 07:03 PM

Quote:

Originally Posted by HUM727

not sure if someone replied yet but the reason ur bike was pinging is cause that gas should not be in your bike, all bikes that i know of, and my sister has that bike, run on premium gas... it may cost 20 cents more butto use 87 u loose fuel economy and performance as well as risk damaging the engine.. figured i share some info on the small amount i know. u might read somewhere that it can take 87 or should.. from my experience that is nothing but bad news

if it wasn't the gas .. the only other reason it would be pinging is sometimes the engine is cold

premium is also much cleaner and on a carburated bike.. that means taking care of the bike much less, cleaning the jets less, and make the spark plugs and valves last just that little bit longer

I know a thing or two about octane and the like. I tinker with this toy in my spare time

:

Turbocharged Buick V6 soon to make about 800hp and 100 more torque

.

Go figure... i have a sport motorcycle as a daily driver and a race car as a toy.... does that seem backwards?

The service manual that came with the bike specifies to use 87 octane unleaded fuel.

My bike usually has no problems using 87octane fuel. In fact, most people that own this bike use 87 octane as well without problems. I can do WOT pulls ripping through the gears with no pinging what-so-ever on 87 octane. Sometimes there will be a little bit of water in the gas when the tanks at the station get low. That's probably what happened.

I've used 87 in the bike for 11,000 miles now. Just yesterday i did scheduled maintained on the bike. I pulled the plugs and used a boroscope to look into each cylinder, and the pistons and cylinder walls look great. The spark plugs looked clean as well. No worries here

Octane is a detonation inhibitor, simply put. It's only beneficial if your engine is constantly pinging even under light load, or if you have a high performance engine. It does not make gasoline burn any better, despite what oil companies want you to think.

HUM727 · 08-23-2009, 02:42 PM

i agree and disagree, im sure that bike can run fine on 87, and i understand octanes as well. maybe its just a personal thing, i have a new civic as my car and a honda cbr 1krr as my go fast toy. ive had 4 bikes and maybe its just been hear say but i wont run a bike weather it be dirt or street without premium.

its not just additives that make gas a higher octane its a different cut from the barrel. and indeed 93 octane will burn cleaner then 87

if u do decide to try a tank of premium one day i would like to know if there is notable differences or not that is worth the extra money.. but its still a bit of curiosity

3-Wheeler · 08-24-2009, 02:36 PM

Both of the previous posts are very close to why octane is important.

The amount of octane depends completely on the speed of the flame front as it propagates across the cylinder after initial spark. If an engine is designed that has a flame speed that progresses too quickly, and the engine designer needs to slow it down, then a higher octane fuel is specified. Higher octane fuels burns more slowly than lower octane fuels.

Now, the Japanese motorcycle engines are specifically designed for lower octane fuels, and will generate the most horsepower using these fuels. *If* you spend the extra and put higher octane fuels in these motors and dyno test the engine, you will see a drop in horsepower due to the higher octane fuel. This is because the flame speed is now too slow!!

When an engine has just enough octane to prevent detonation, then no further increase in octane level is required. Going higher in octane will just cost you more in fuel and reduce the specific output of the engine. The right amount of octane = the right amount.

Jim.