Motorcycle mileage
 

I have a 2002 Honda XR650L.

So far I've put street tires on it, filled it with 5W-30 Mobil 1 oil, reduced the idle speed, removed the brush guards, and overinflated the tires. I coast rather than use engine braking. With careful driving after these mods, the mileage went from about 48 to just over 50 mpg, maybe 52 on a good tank.

The mileage doesn't vary much, regardless of whether I drive on the highway or in traffic. I don't understand it.

And I don't understand why a single cylinder 650 cc bike would get such crappy mileage. Harley Sportster 883 twins are rated 57 mpg highway. Shouldn't the smaller, lighter bike get better mileage?

I'm stumped as to what to try next. Anybody know of closed loop EFI for motorcycles?

I think the big problem with motorcycles is wind resistance. If you were to put a very slick fairing on it I'll bet you could break 70 mpg. Still, motorcycle engines tend to be high performance and tend to suck gas. My Honda CX500 gets 45 mpg which is less than my Suzuki Swift car with an engine nearly 3 times the size.

Q

Bike engines are pretty high-strung, so they tend to get bad mileage. Rich mixtures and very aggressive valve timing. If you want to mod it, start with cams. Harleys are 2 valve, and they aren't about max horsepower (at least stock), so they naturally get better mileage.

Air resistance is a huge factor on bikes, but it gets hidden by the motors. The best I've heard of was to take a Ninja 250 and swap sprokets: nets 90 mpg if you ride carefully. The sky is the limit with aero shells.

make sure not to lug your engine by running it to slow, I have a vacuum gauge hooked on to my honda cb125 and have found that haveing it reved pretty high, 7,000rpm (9,500rpm red line) seems to yeld the best results as it takes advantage of the agressive cam that is designed for high revs, and the throttle is hardly cracked open.

Got 56 mpg while tooling around town. Lubed and adjusted the chain and changed the oil (Mobil 1 5W30) just prior. Best tankful ever.

Thumbs up sludgy! Makes me wanna get one. If only they were like 50 bucks, :p

Put some skin tight clothing on. It has to help at highway speeds.

You dont have the "Village People" leather suit for that do you?

I have a leather jacket to avoid road rash, but no leather pants. I usually wear jeans. I'd love to wear full leathers, but the wife thinks I'd attract Village Peephole types.

I'm running amsoil 10w40 synthetic motorcycle oil in my motorcycles, because the friction modifiers found in some synthetics can soak in to the clutch plates and make them to slipery to grab, but mostly I think that is aditives like molly.

making sure you have the stock air box on your motorcycle is something that alot of people make the mistake with, normaly when you remove the stock air box you reduce how consistant the intake vilosity of the incoming air is, and it screws with yoru fuel air mix, and from what I've found, if you want to increase your air intake, replace your paper filter with a foam filter.

Not to worry, you'd be more likely to attract Mad Max types.

https://img.villagephotos.com/p/2006-...ldenYouth.jpeg

I've been thinking of trading in my XR650L on a bike that gets better mileage. The Feb 06 issue of Cycle World gives some real-world testing:

Honda Rebel 250 twin (mini cruiser) 78 mpg
Suzuki DR200 single (dirt bike) 68
Kawasaki Ninja 250 twin (sport bike) 74
Yamaha TW 200 single (dirt bike) 79
Buell Blast 500 single (sport bike) 71

Not tested, but published on Suzuki site:

Suzuki GZ 250 cc single (standard bike) 82

I like the styling of the Blast, but the Suzuki gets better mileage. The Ninja gets slightly less mileage, but goes 100 mph.

On the other hand, I could just buy a comfy Corbin seat and a bigger tank for the XR650L.

What are your Gassavers thoughts?

My Kawasaki Zephyr 750 gets about 53mpg normally and sounds lovely doing so. Mind you, I never really rode the bike trying for economy... too much fun to be had.
I have also commuted a few times with my 92 Honda XR250L and the best I saw was about 78mpg.
I no longer commute on my 250 because I felt like I was over stressing the motor cruising at 90 or 100km/h when it tops out at about 120km/h.
I say just enjoy the bike, chances are if you go down to a 250 or so you'll end up missing the grunt of the 650.
BTW:To be on the safe side, I'd go back to the recommended tire pressures on the bike.

My old bike bothers me, for being so small, and light (400cc, 400lbs), it gets horrible gas mileage! only 30-40 mph. I'm thinking something is wrong in the 30 year old carbs. Power is still good, 100 mph in tight pants, and t-shirt, 95 in a sweathshirt, 95 in a coat too, but takes longer to get there, probobly had more power from the cold air too.

I've always been a fan of good aerodynamics, top speed seems to me to be an easier way to measure improvement or not in aerodynamics.

Here's what you have to do to get better mileage . . .

https://autos.ph.groups.yahoo.com/gro...cooters/photos
https://autos.ph.groups.yahoo.com/gro...oters/messages

Harley Davidson is installing fuel injection on all of its 2007V twins, including the entry-level 883 Sprortsters. I'm not sure whether this is closed loop EFI, or even multiport EFI.

EFI is so mundane on cars as to ridiculous to even think of a carbureted car these days. But none of the Japanese motorcycle manfacturers use it.

I wish I could get an EFI kit for my XR650L. I'm sure it could be tuned for better mileage than the carb provides.

Do you know if 4-stroke bikes have to meet any emission requirements?

I have a 1986 V twin Morini K2 350cc 100mph top speed 80-85mpg and I don't even ride it.

Actually, there are quite a few fuel injected motorcycle out there. Most Honda's are, there are a few Suzuki's that are, Kawasaki Ninja's are, if you want one, they're definetly out there for you.:D

Yah, I know, the crotch rockets have FI. But what about dirt bikes and other thumpers??? Why isn't FI used across the board?

I was going to get a 07 Harley then pulled my head out.

Looks like Im going to get a 07 Yamaha Road Star Warrior.

Dont care so much about mpg, as I do low end fun grunt.

I'm really not sure on this one. I'd imagine cost/weight/complexity is a factor with the other bikes (although I find f.i. far easier to work with) . With Harley's, I'ts probobly more tradition, also the reason they use out dated technology all around. In the future there is plans for Harleys to be F.I. as well though.

For the smallest of bikes, they run f.i. so they don't need a battery, sensors, and related heavy bits, they are pure simple machines.

Hopefully someday we'll also have F.I. ULEV lawnmowers, or plug in ZEV lawnmowers and such it will probobly be too late by then anyways.

Vmax dosent have much down low. Its all pretty much made on the top end. Plus couple that with way nasty forks and brakes and the jacking shaft drive. They kind of a suzi bike. Ive heard rumor that its suppose to be redesigned for 08.

I think must new Harleys are FI.

You are correct, My mistake:o

I think what is most amazing about bikes not being all EFI across-the-board is that Kohler makes closed loop EFI for some of their garden tractor engines.

Think about it: You can buy a garden tractor with closed loop EFI, but not all motorcycles.

Dosent suprise me a bit that all bikes arent FI. Anybody that builds up there big V-twins or other FI bikes. Dumps the FI, O2 sensors and all the other EPA stuff. And alot of these folks dont or wont care what the EPA or anybody else has to say about it.

After I get my Warrior. It wont be stock for long. :)

carburators are cheap to build, and the molds, and facotries are already set up to build them, the cost of a replacment carburator from honda for my motorcycle (if they still made them) would be around $120, a 4 wire o2 sensor can cost almost that much, so how much are tiney fuel injectors going to cost, and the computer, throttle body? fuel injection on motorcycles is going to come in a few years, but unless you want a really crude system, or a large engine (like a riding lawn mower engine 600-800cc) that can use off the shelf parts, making a fast, small fuel injected engine is going to take time to work out it sounds like.

Ryland, have you ever considered adding fairings to your bike? While browsing the internet, i stumbled upon 50cc race bikes haha, they're actually quite speedy! 100+ mph from around 20 h.p.! Considering that, these fairings must be quite efficient since my bike has almost twice the horsepower, but much lower top speed...

https://www.madmalc.screaming.net/50c...s/tormo_02.jpg

I'm playing with the idea of trying to make a similar fairing for my 400cc bike, the only problems I see are cooling to my air cooled engine. With no temperature sensors, I see no way to measure this either.

Red91sit, that bike is way cool! Where can I buy one, or just the aero parts in the US?

You can measure combustion chamber temps like they do in aero engines with a sensor that goes under the sparkplug washer , and you can measure exhaust gas temps too.

No reason also why you cant mount a temp sensor just under the head wedged between cooling fins up tight against the barrel.
If the surface is clean and you put a few MM of silicone over it , it should be quite a reliable gauge of temp.

I never even thought of that :O great thinking.

Sludgy-

I have been having difficulty figuring out exactly what these litte bikes are :S they seem to be made from scratch, bought as kits, bought like a regular motorcycle, and pieced together from variuos motorcycles.

Here's one i found for sale

I think these are fairings for sale

This one carries lots of the "bubble" style fariing :thumbup
[IMG][/IMG] :