Fuel efficiency and performance for cc ranges

[jmillheiser]

look at the weight and/or operating habits of modern bikes.

Modern cuisers tend to be quite heavy and pack sizeable CCs compared to older ones.

Modern sportbikes though much lighter than old ones are much higher strung in the engine room, plus many (possibly even most) sportbike riders like to twist that right wrist a LOT. RPMs also have a lot to do with fuel economy.

Higher RPMs = more injector pulses or more vacum in the carb = more fuel used.

The blast engine is a very low revving design. The engine in the blast in never operating in a very high duty cycle so it has less chance of detonation running a really lean mixture.

Most stock bikes and cars run richer than they need to to reduce NOX (Nitrides of Oxygen) emissions. These emissions are most prevelant on vehicles with very high combustion temps (sportbikes, high performance cars, diesel engines). NOX is one of the primary compenents of visible smog along with ozone and soot. The upside to high combustion temps though is lower emissions of Hydrocarbons, Carbon Monoxide, and Carbon Dioxide, not to mention more power and better MPG.

The better solution is Low sulfur fuel (europe has used this since around the turn of the millenium, the US adopts it in 2007). The lowered sulfur conent lowers NOX emissions far more than lowering combustion temps especially in diesel engines where is also significantly reduces the soot content as well.

[mydlyfkryzis]

I don't know if newer versus older is a good comparison. My 1976 CB360t gets about 45 MPG and my 1991 Nighthawk 750 gets 47 MPG avg.

Odder yet, my 1969 350 (which I don't have any more) got about 55 mpg. The CB360 is essentially the same design, similar weight, and 6 gears instead of 5, yet the 350 was faster and had better gas mileage. The 750 falls in the middle on mileage, yet has 100% more power than either.

All in all, though, I wouldn't want a motorcycle that got less than 40 MPG. Unless it had a 15 gallon tank. No range with a small tank and low MPG.

[Scoutmedic]

According to the Suzuki Dealers, the GZ250 is getting 82 mpg hwy. That's actually what I'm leaning towards. When you look at the price brand new of only $3,200 and the low insurance cost on a smaller displacement bike, it can be quite cost saving.

I estimated monthly insurance, montly payments, 70mpg at $3.00 / gallon would save me about $200 in 6 months vs my Subaru that is paid off. And that was just driving to work. It didn't include running errands.

Would I LIKE a bigger, sportier, insert-your-adjective-here bike? You bet I would! But, the reality of low pay, high gas prices and living in the snowbelt means getting something that's cheap and will actually save me some money initially.

Unless of course there's a millionare browsing the site looking to throw some money at a lowly but deserving public servant??

[Kal]

125cc's returning just over a 100mpgUS in mixed riding in city traffic and dual carriageway speeds.