gas mileage

[Zapkin]

I have been reading this forum for months and watching a lot of videos about these bikes. Most people modify them for speed, but I am curious about which modifications would primarily affect gas mileage. I am not interested in going fast, I want to be able to travel longer distances. Apologies if this topic has already been discussed, I have difficulty with search functions.

[Bill Hilly]

Originally Posted by Zapkin

I have been reading this forum for months and watching a lot of videos about these bikes. Most people modify them for speed, but I am curious about which modifications would primarily affect gas mileage. I am not interested in going fast, I want to be able to travel longer distances. Apologies if this topic has already been discussed, I have difficulty with search functions.

For most gas mileage is hard to pinpoint, because these bikes get used differently, by most who buy them. I can say that in my experience,they are not real thrifty on gas for a 230 cc, but actually no motorcycle is really great on gas compared to an economy car. I have a Hawk, a TBR7, a Savage, and a Virago XV 250, and the Virago gets by far the best milage, even with my weight, I get around 75-80 mph , but it takes premium fuel. My Savage makes torque, but is not a high rpm motor, and it gets probably a bit worse than my Chinese bikes, but not by much. I would guess that a lighter person on a properly geared Hawk, or TBR7 could get around 65 . I have bags on all my bikes, and do run errands with them when I can, but as far as practical, they can never be as practical as a little car like an Elantra, or Civic, or any small car that gets 35-40 mph, but motorcycles are fun, and that's were they have the advantage.

[XLsior]

It also depends on the roads/terrain being traveled.

The 200-300cc range does not have the same economy range as a 125cc platform cycle.

But If you're doing highway speeds than a lower revving twin cylinder will probably get better economy than a screaming single piston.

If your averaging about 50mph on twisty back roads with some gravel and dirt than the average dual sport will get the job done better than the smaller and larger displacement alternatives...

The optimizations that often get discussed here are more about dialing in the untapped potential rather than maximizing top speed which is also more about keeping up with average road speeds and other motor vehicles.

How this effects economy is subjective as same gains will cancel out negatives.

60mpg is a rough baseline for the CG250.

[TominMO]

Keep your tire pressure up, get a windshield to clean up the drag, and ride at a constant speed of about 50 - 55 MPH in high gear. That's most of it right there. And of course tall gearing via the sprockets.

[Hunnicutt]

I installed a 112 main carb jet on my TT250. Everything else on the engine and drive train is bone stock. On rare occasions, I ride my TT250 260 miles round trip to my ranch. Stock tires at 32 PSI. Road speeds are 35-65 MPH. No highways. I get a consistent 63 MPG.

[Megadan]

Want to maintain good mileage, then stick to a pz30/VM26 clone and dial in the jetting (especially the needle).

As others have said, a lot of it is how you ride and where you ride. My first Hawk had an exhaust, vm26 carb, and a modded airbox with 17/45 sprockets. I had that carb dialed in perfectly.

If I rode it at a steady 45 to 55mph on relatively flat terrain I could confidently say I would average around 80mpg. I say that because one trip I went on saw me on a back highway with a few hills mixed in at an average speed of 55. I roughly calculated 74mpg

That same bike holding between 60 and 65 would drop into the 60mpg zone simply from being wide open at 7500rpm.

Total mixed on road mileage on average for that bike was around 65 to 68mpg

EDIT: Not sure why there is a thumbs down in the title. Didn't mean to add that and I can't get rid of it lol. DOWN with fuel economy!

[Zapkin]

well I ordered the 17 tooth front sprocket for it. i have a surplus 17 tooth for the xpect. not sure if I can return it to the same place or maybe someone on here could use it. let me know if anyone sees and is interested.

[Boatguy]

and other than everything that has already been said, it’s really just a matter of how much gasoline is going in to get burnt.

that’s why the fuel injected ones get a little bit more miles per gallon and run a little bit more lean. So maybe you can lean out the carburetor as much as you can safely do.

and from there, don’t open the throttle all the way up. Use as little throttle as you can to go as fast as you need to. That’s good fuel economy. Along with all the other stuff said above.

[Thumper]

I always run premium since the thing gets 50+ mpg.

In my experience, opening up the exhaust and other high performance measures allow you to use more fuel efficiently and accelerate faster, but also get at least as good mileage when you drive gently since the engine is running more efficiently. A modified engine/exhaust can get as good or better mileage, or slightly worse than stock since it can use more when you really get on it twist the throttle.

Bottom line is that you will get better than 60mpg if you accelerate gently and don't do a lot of heavy acceleration, AND keep the speed down in the most efficient rpm, maybe 4000. The exact rpm may be different, but make the engine work harder, fuel economy will drop. I can squeeze 45+ from my 1.4L Jetta (turbo) by allowing it to go faster on downhills while gently accelerating, and letting it slow down, lifting my foot of the throttle slowly on the way up the hill (using momentum). I am a hypermiler, but I try to stay out of the way.

[Zapkin]

To be honest I kind of had a feeling that most of the mods that would improve top end probably also increase mileage if you baby it.

[TominMO]

Slightly off topic but relevant.

I used to have a Ford Festiva that I did all sorts of mods to. One of the things I was most interested in was gas mileage. I found that with the stock 1.3L motor and 5-speed, and 155/80-13 tires, it would actually get these mileages, when driven at a constant speed for about 90 miles:
45 MPH = 62.5 MPG
55 MPH = 58.0 MPG
60 MPH = 52.5 MPG
65 MPH = 45ish MPG (I forget exactly)

When I replaced the stock motor with a 1.8L Mazda SOHC, bolted to the same transmission, and had some head work done on it, the HP increased 50% over the stock 1.3L, and the gas mileage only suffered by 10%, when driven as in the previous tests.

55 MPH was a good sweet spot. Not much MPG improvement at slower speeds, and you got someplace quicker than at 45 or 50 MPH. Above that speed, wind resistance and higher revs kill mileage.

[Megadan]

Originally Posted by TominMO

Slightly off topic but relevant.

I used to have a Ford Festiva that I did all sorts of mods to. One of the things I was most interested in was gas mileage. I found that with the stock 1.3L motor and 5-speed, and 155/80-13 tires, it would actually get these mileages, when driven at a constant speed for about 90 miles:
45 MPH = 62.5 MPG
55 MPH = 58.0 MPG
60 MPH = 52.5 MPG
65 MPH = 45ish MPG (I forget exactly)

When I replaced the stock motor with a 1.8L Mazda SOHC, bolted to the same transmission, and had some head work done on it, the HP increased 50% and the gas mileage only suffered by 10%, when driven as in the previous tests.

55 MPH was a good sweet spot. Not much MPG improvement at slower speeds, and you got someplace quicker than at 45 or 50 MPH. Above that speed, wind resistance and higher revs kill mileage.

The engines peak horsepower may have been 50% higher, but it only takes X hp to go a certain speed. The dip in mileage would have been more severe if you drove everywhere at full throttle all the time, but at cruising speed, 10% is plenty reasonable for a 40% increase in displacement.

[Zapkin]

The knowledge of folks on this forum never ceases to amaze me. One reason I changed to the carbed hawk was the desire to learn about carbs and just have something I don't mind tinkering with. And of course. it saved me 400.00 which I can then apply towards upgrades on the hawk.

[TominMO]

Originally Posted by Megadan

The engines peak horsepower may have been 50% higher, but it only takes X hp to go a certain speed. The dip in mileage would have been more severe if you drove everywhere at full throttle all the time, but at cruising speed, 10% is plenty reasonable for a 40% increase in displacement.

Actually now that I remember correctly, it was a 60% gain in power with the head work, 4 into 1 exhaust and a pod air filter. But yeah, that's what I figured too. The extra power meant you didn't have to press the pedal down as far, so it sort of equals out at a constant speed.

[adb1779]

Hi,

I commute from north of Philly to NJ (37 miles round trip) and use regular exxon. The round trip has ~93 traffic lights. During the summer I get 70/71 mpg (gps miles) when it gets cold I get upper 60's. The TBR7 is stock save the 17/40 gearing. I run Amsoil 10-40 with stock chain.

Al