Topic: mpg on 74 550

[BruceA cb550]

what should be the expected mpg on a stock 1974  cb550 with 20,000 miles.  I,m only getting 40mpg, is this normal for this bike?

[Philly550K1]

i get 39 on the nose every tank, and i'm overdue for a tuneup.  33k miles on my 75....

a "performance" bike in its day, designed before the oil crisis....  not a bad deal.

[Gordon]

what should be the expected mpg on a stock 1974  cb550 with 20,000 miles.  I,m only getting 40mpg, is this normal for this bike?

You could probably get a little more, but a lot of it depends on your riding style. 

[fang]

On a several thousand mile trip (with my wife and gear) I consistantly got in the low 60's on my '76 CB750.  I believe at that time I had the sprockets geard for better fuel economy.

-fang

[TwoTired]

what should be the expected mpg on a stock 1974  cb550 with 20,000 miles.  I,m only getting 40mpg, is this normal for this bike?

What gear are you driving in?

Do you keep your chain well lubed?

What tire pressures are you using?

Are you using gasohol? (Reduces fuel economy)

When was your last complete tuneup?  S/B 3000 mile intervals.

Is your air filter clean as new?

On a trip, my 74 CB550 would get 50 MPG with stock gearing, back when pump gas was ALL gas.  I wouldn't expect more than about 45 MPG with today's pump gas.  Around town in the lower gears is not a fair mileage test IMO.

Cheers,

[BruceA cb550]

less than 400 miles on bike since restoring from sitting in barn for 20 years.
rebuilt carbs, cleaned tank, oil and filter change, new air filter, frt forks redone, brakes redone, new cables, new chain and sprocket factory specs, new points and plugs, new tubes/tires inflated to specs.
run 89 octane unleaded mostly around town and some country roads.  No long road trips as of yet since I'm still messing with mixture which I think I've got pretty close now based on performance and plug chop.  Original owner thought it was close to 50mpg but might be due to different gas as you stated.
This is my first bike so I have no experience to judge gas mileage.      thanks for your input

[volthause]

I did some spirited riding this past weekend (about 200 miles worth) on my '74 550 and got right around 40 mpg.

[Chris Schneiter]

yeah, seems like you're doing ok..I don't know about 550's, but on my 750, the best I've gotten was about 45 (highway all day), and in the city, sometimes it's as low as 23!...geez, my CAR gets 33 on the highway!

[DrMark]

I average about 45mpg on my 1978 550K. Mostly cruising country roads. Stock everything, except air filter....using a UNI.

[TwoTired]

less than 400 miles on bike since restoring from sitting in barn for 20 years.

Okay then, the congealed 30 tear old grease in the wheel bearings will likely eat some fuel ecomomy.  But, I wouldn't worry it.

brakes redone

Make sure they are adjusted for no drag.

run 89 octane unleaded

Not necessary.  Compression ratio is only 9.0 to 1.  Regular 87 is fine.

Ride safe and enjoy it!

Cheers,

[grumburg]

yeah, seems like you're doing ok..I don't know about 550's, but on my 750, the best I've gotten was about 45 (highway all day), and in the city, sometimes it's as low as 23!...geez, my CAR gets 33 on the highway!

I figured on a proprtional basis (weight and engine displacement) a 3500 lb car with a 4.4 litre engine would get 5.7 mpg vs 40 for a 420 lb. .55 litre bike. Of course, the car would have 400 hp. Honda used the old school method of making HP, lots of fuel.

[popeye]

Dang it Bruce I think we got twins born a year apart....I just got my rolling basket case on the road last week.  I done all the same stuff you did..plus..cam and rocker cover, pan gasket, clutch cover gasket, shifter seal and a new horn....I got 40 mpg..until the float stuck on #4..then I got about 10..I'll fix that tomorrow..

'75 550 k1

[popeye]

BTW....I'm running 105 mains..uni-filter pods..Mac 4-1..she screams..YEEHAA!!

[BruceA cb550]

by the way Two-Tired, I forgot to mention that I replaced the wheel bearings as well so shouldnt be any drag there.
Popeye, I've got some uni pods that I might try.  Currently running stock Honda filter but have to lean the needles all the way or it runs rich.  I assume my jets are stock 100s but I didnt think to check them when rebuilding carbs.  Think I'll set needles on middle slot and put pods on and see what happens.  Hell any gas mileage that the bike gets will beat my 4x4 crewcab any day and the bikes much more fun.

[jbailey]

When I first got my 1975 550K I got about 35 or 36 MPG.  Over the first winter I installed NGK Iridium plugs, Rotella T Synthetic 5W-40 oil, a UniFilter (foam Air filter), filed and set the points, set timing with a timing light, replaced rear sprocket (stock was 37T, new is 34T), and adusted valves.  I expected an improvement, but couldn't believe the 50 MPG average I got.  I still am running close to 50 MPG on average with mostly backroad 60 MPH driving.

I can't say for sure what made the most difference, but the rear sprocket dropped my RPM's at 60 by about 500.  I really didn't notice any drop in performance.  I actually prefer the lower cruising RPM.

[Gordon]

yeah, seems like you're doing ok..I don't know about 550's, but on my 750, the best I've gotten was about 45 (highway all day), and in the city, sometimes it's as low as 23!...geez, my CAR gets 33 on the highway!

You should be getting better mileage than that.  750's should get close to 40 in town and 50 highway, at least in my experience. 

[74cb750]

1976 cb550, never better than 40mpg, but then again I (ahem)
sometimes ride faster than 55mph.
peace,
michel

[screemn2]

what notch do you have your needle in?

[333]

What notch is yours in, because you've just bumped a thread that is 8 years old. The guy that started it isn't even member anymore.