expected mpgs for a 1978 suzuki gs550e

[tc862011]

what should i be expecting for mpgs on my 1978 suzuki gs550e

[cowboyup3371]

What maintenance have you done? How do you ride - do you romp on the throttle all the time or are you grandma? Where do you ride - highways or in town?

My 81 550t gets upper 40s for the most part; sometimes 50+ when I lived in CO and went up to the mountains but I'd say upper 40s will be good.

[tc862011]

I Have done everything to new carbs. Rebuilding top end. New rings and rebored cylinders. Everything on the frame has been changed that needed to be for the wheels. I am getting about 35 -40 mpg when I ride I get on it a little bit here and there. But when I am cruising I usually stay in 55h and the rpms are at about 4 to 5 grand. I live in the city so it takes some stop and go to get the nice riding with no stop and go

[AJ]

My son gets 42 to 45 on his 1985 GS550esf.

You'd think a small bore 4 cylinder would get better mileage than a bigger bike, but that's not usually the case. My busa gets about 42 - 47 mpg, and it only takes a tiny bit of throttle on that to send my son on the 550 whomping on the throttle to keep up.

[razor02097]

I have a few questions for you...

How are you calculating MPG? Keep in mind that calculating MPG on a bike is more difficult than a car. The fuel tank on the bike is smaller so a slight error can make end number way off. For instance if I went 100 miles on my bike and filled up with 2 gallons I would calculate 50 MPG but if I put in 2.1 gallons the number drops to 47.6 MPG... one tenth of a gallon is basically a can of soda pop.... 12 ounces of fuel can make a 2.4 MPG difference!

Are you calculating MPG by your odometer/tripometer? Try calculating it by route. Your odometer may be off. Especially if you have a newer front tire "equivalent" example is my bike's original front tire size Vs the new size causes a -6% error. This in turn causes the odometer to read 6% less mileage than I actually did or about 6 miles every 100 miles.


Calculation errors out of the way you say you do mostly city riding? What kind of hills do you have in the city? Hills will absolutely kill fuel economy.

Do you have stock sprockets on your bike? A different gear ratio may help if you do a lot of lower speed riding in the city as help some in stop and go.



All that aside 35-40 isn't terrible. I really think it is probably just calculation error.

[tc862011]

well i filled up my 550 about 4 gallons. and i have gone 125 miles and had to put it on reserve. i dont know how big reserve is so i am thinking i can get about 140, so 40 divided by 4 is 35

[razor02097]

How many miles did you have when you filled? Reserve comes from the same fuel tank so it won't matter when you put it on reserve.

[Toasty]

Keep the RPMS up in the power band too. I've ridden to work cruising at 65 in 6th gear (~5000rpm) and gotten 45mpg, but when I bumped it up to 70-75 in 6th (6-7000rpm) I got 51mpg.

[tkent02]

550s need to spin to wok efficiently, it should be over 50, even whipping it good it should be near 50.

Small bikes have nearly as much drag as big ones, so the mileage isn't much better, my 1100G gets 45 - 47 mpg in all around use.

It depends a lot on your fuel's alcohol content too.

[razor02097]

He probably has mechanical type carbs. That will make a difference in fuel economy.

[tc862011]

i dont have the vaccum carbs i have the metal slide carbs. i usually cruise at abot 5,000 rpms when i am in cruising speed. what do you mean 550s need to spin to wok efficiently. and i know the reserve is from the same tank. but you need switch it to reserve after a certian point. i dont know how much is left in the tank after you switch it to reserve

[tc862011]

i do have mechanical carbs not to vaccum carbs. what does it mean when you say 550s need to spin to wok efficiently, and when i am at cruising speed i am at 5,000 rpms.

[hampshirehog]

He means the 550 like to run at high revs. I would be pleased with 50 mpg. I don't get that - and our gallons are bigger.

[Missile99]

What Tkent means is at lower rpm's the bike is not within its powerband and requires more fuel to do the same work. (typical riding conditions)

For example, you're going to be travelling at 65 mph. In 6th gear the rpm's are 5500 and 5th gear you're at 5800 rpm. (just an example) The bike may get better fuel mileage in 5th gear because it's spinning faster but more efficiently and therefore requiring less fuel. Of course there is a happy medium somewhere, a balance between rpm and throttle input depending on many things.

Another example of more rpm but better mileage:

Two identical cars, same engine and everything else except the transmission.

1) Automatic: 65 mph it's at 1900 rpm
2) Manual: 65 mph it's at 2300 rpm

The manual may be turning more rpm but getting better mileage because less throttle input is required (and because the manual is directly driven through gears and loses little effiency compared to flinging fluid around). Of course this is not always the case with cars anymore because of how many speeds autos have. All I'm saying is keep in mind that lower rpm's doesn't mean that you are saving fuel.

One more thing is that too low an rpm, meaning lugging the engine at all, reduces its life. I'm not going to climb a hill at 2500 and floor it in a high gear. I will downshift and spin it to 4500 (car not bike) and keep the thing from struggling.

[Spyder]

well i filled up my 550 about 4 gallons. and i have gone 125 miles and had to put it on reserve. i dont know how big reserve is so i am thinking i can get about 140, so 40 divided by 4 is 35

Wait, huh!?! First off, lets say that your not getting "tire size miscalculations" as stated above. You really have to be accurate on mileage to gallons.

1. Fill the tank to the bottom of the inner lip.
2. Ride it for however long, lets say 112.3 miles when you pull back into the gas station.
3. Fill it back to the inner lip of the fill hole.
4. take the EXACT amount of fuel you put in, and divide the EXACT number of miles you rode (ie. 112.3 divided by 2.76 gallons).
5. THAT number is how many miles your getting per gallon.

Like stated above .10 of a gallon can change that number by 3-4 mpg...
So if you put 3.86 gallons and just divide it as 4 gallons it will throw you calculations down quite a bit.