Daves Mods Done ,and So Is My Gas Mileage

[rebelventurer]

I dont know how in the world you can get 40+ mpg, unless you have a rope with a hook on it, ( for hooking onto cars and trucks and getting a free pull). My bike jetted uncorked and with 14-48 gearing ridden mostly dirt 75/25 will hit reserve between 90 and 115 miles, with a clarke 4 gallon tank and takes just over 3 gallons to fill, (just after switching to reserve) I do ride pretty aggressive and sometimes illegal, the front tire is for turns and holding the bike up when parked, and maybe I am travelling a little farther than the odometer says, since its connected to the low flying front tire. But I figure that works out to 30- 38 miles a gallon. However to get the 115 miles I have to ride very restrained, and it takes a lot of the fun out of it, for me anyway, so I can say I average around 30.

[rebelventurer]

In response to the guy who stated cars are getting better mileage etc... the motor and electrical controls on the xr650L are ancient compared to the car technology of today, shall we say 70's engineering. Where as cars have fuel injection, variable cam timing, electronic spark control, overdrive transmissions, low aerodynamic drag, etc... Comparing the L pig to a car of today is similar to comparing a 2006 civic to a 1973 montecarlo. I guess if you were to make the comparison between the L pig and a 1973 montecarlo the L gets great gas mileage.

[2000 xr650r]

To the car example heres how i see it. Power to weight ratio of xr650 = 6.6pds per horsepower. Get a car that weights 3500pds and has the same power to weight ratio. That car would have to have over 500hp. What mileage is that get? My point is if the bike was underpowered and had the same power to weight ratio as a economy car, it should get good mileage.

[motomonte]

How the heck do you arrive at that, unless your riding the bike in a aggressive illegal way to get around traffic?

Why does a bike take so much gas towards a car? I know they (enduros) are not near as areodynamic as a car but with only weighing 300 lbs how comes they don't get a lot more then 40-50 per gallon?

Not agrresive,maybe illegal,definitly fun.... ?

Really,at every stop light I gain a few minutes since lane splitting is legal here

[Beyond The Pale]

To the car example heres how i see it. Power to weight ratio of xr650 = 6.6pds per horsepower. Get a car that weights 3500pds and has the same power to weight ratio. That car would have to have over 500hp. What mileage is that get? My point is if the bike was underpowered and had the same power to weight ratio as a economy car, it should get good mileage.

Well the "oversize"' engine that a bike has is part of it. In my experience most gikes get between 40 and 45 miles per gallon. Doesn't seem to matter what size the engine is. Some small engined bikes do get better mileage. For example, some people get 60 to 70 MPG on a 250cc Ninja. Other small displacement bikes also get similiar mileage.

The major factor is drag. A motorcycle is horrible in it's areodynamics. Massive drag. Economy cars have like one tenth the drag of a bike. That's how small cars can get 40+ MPG.

[JoeBlow Kokomo]

I would think it may even out though? Sure you may use more fuel but since you have more power you don't have to open her up as much to accomplish the same job as before.

You see it all the time with automobiles.......... every few years some get a bigger motor slapped in, gain more horsepower, yet get better gas milage.

A lot of that is because they put very high gear ratios on them. They've got the power to pull them and it helps the mpg a LOT. Buddies 5.0 Mustang gets 30mpg highway. That's amazing.

[Poe]

Buddies 5.0 Mustang gets 30mpg highway. That's amazing.

Sorry... gotta call B.S. on that one. I had an '87 LX 5.0 (fuel injected) 5-speed Mustang that had the 2.73 rear gearing (a.k.a. the "highway gear") - bone stock except for a K&N air filter and Flowmaster mufflers (welded into the stock cat-back) - and I never saw anything higher than 25 MPG - even with the cruise set at 65 MPH on a flat interstate. My '96 Mustang Cobra would get that too - until I put 4.10 gears in it. That's still pretty good, but certainly not 30 MPG.

I have heard that C5 Corvettes can get very close to that though. They're barely running above idle at 65 MPH in 6th gear.

[Huffa 2]

So how much increase in mpg's do you guys think with fuel injection, if they would get it that is.......... 15% maybe ?? Think they will ever see varible valve timing?

I could swear I thought I got over 50 on a trip easily with my 83 XL 600 but I guess I must be mistaken Maybe gas was more potent back then hence a bit better milage?

[Billahjack]

The piston slide in your carb is the venturi adjustment to keep the air at high velocity. You wouldn't gain anything from a two barrel carb except more weight and complexity. If you want a gain, you need to go to fuel injection for precise fuel delivery.

[frog13]

I had a 1990 GT 5.0----If I kept my foot out of it I also recorded several 30 mpg days---No JOKE or BS!!!!.

[Denn10]

Well lets not forget theres alot more than just how many miles to a tank. How much do you weight? Where are you riding town, hwy 55mph, or freeway at 75 mph, Do you rip the throttle alot? What gearing are you using? I am close to 300 lbs and i take mine to work on the freeway or riding around town so im screwed either way, fast or stop and go. I prolly get about 35-39 per tank on freeway and who knows what around town. Sucks but oh well gas is cheap these days!!

[Denn10]

So how much increase in mpg's do you guys think with fuel injection, if they would get it that is.......... 15% maybe ?? Think they will ever see varible valve timing?

Id bet that 15% isnt too far fetched if they made a nice FI 650 Dream on LOL i know

[martinfan30]

i never get worse than 42 and i'm always on the gas! which is part of why i got pulled over LOL!

unless i have my full load of camp gear then its high 30's

[BOOGGEEMANN]

That's what happens when you unleash the beast, it has a tends to want to eat more. I did all the aftermarket mods and then some. 82mpg to about 52 running 91 octane or higher ONLY!!!!!! The best part about it is now I have a full time job keeping the front tire on the ground...... For better mpg after mods, try a bigger piston, with a hot cams camshaft, and a hotrods crank shaft. It will cost a pretty penny but save you lots of cash in the long run.

[martinfan30]

That's what happens when you unleash the beast, it has a tends to want to eat more. I did all the aftermarket mods and then some. 82mpg to about 52 running 91 octane or higher ONLY!!!!!! The best part about it is now I have a full time job keeping the front tire on the ground...... For better mpg after mods, try a bigger piston, with a hot cams camshaft, and a hotrods crank shaft. It will cost a pretty penny but save you lots of cash in the long run.

Welcome to TT Booggeemann!

How does it crank over when cold for now ? Did you go with JE or Wiseco?

[BOOGGEEMANN]

Get the XR"S ONLY oil temp dipstick so that you con keep a more accurate idea of the temp of your bike. If it's stone cold at about 50* F I pull the choke all the way in for 10 seconds, then mid choke for 5 seconds, and then let it idle until 100* F. It also helps you keep track of when your pide and joy might be running a bit warmer than usual, at least you won't have to worry about over heating. OH yeah, anything over 275* F is way to hot to ride, 300* F just park it and walk the rest of the way.