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Is 48 MPG Good For A 550?

  • Thread starter Thread starter Hoomgar
  • Start date Start date
H

Hoomgar

Guest
I tested my 550 and I am getting and average between 47 to 49 MPG out of it since I cleaned the carbs out and got it running right.

What is the average MPG expected out of a 550cc street bike?
 
Thats pretty reasonable as an average mpg. A lot of modern bikes, because they go more for power (well, a lot more than older bikes!) tend to be a bit hard on the juice.
 
That's good, Hoom. I get 46-50 mpg on my GS550E with the higher number coming from not bouncing it up to redline at 9500 all the time. By the way, it starts now without the choke ! I don't know what I did beyond having the pilot jets freed and set at 1 1/2 turns from seated but I give it about 1/3 throttle and she's rockin' and rollin' at about 2000 rpm! Great bike. Bone stock with the stock airbox and filter and an eBay MAC 4-into-1.
 
Pilot jets? I thought the pilot jets were inside the bowl under those rubber plugs?
Do you mean the ones on the outside of the carb? I thought those were the mixture screws?
We need to come to some consolidation/standardization on what screw is called what...
No wonder I can't get any of my carb settings right...everyone is talking different things with the same terminology.
This sucks... :(

Dm of mD
 
The screws on the top of the intakes (usually under sealed plugs) on CV carbs are indeed called pilot jets. Don't ask. I've heard them called "mixture screws" and "air screws" too but according to R Riles at motorcyclecarbs.com they're actually pilot jets. They control the mixture from idle to about 1/4 throttle. When they're adjusted right you get a smooth running engine and a nice quiet clutch. I think on Mikuni VM carbs (slide throttle) the pilot jet is inside the carb body.
 
Okay, henceforth i am calling them "Pilot Jets". References/memories updated.

Thank you,
Dm of mD
 
1985 GS550EF, averages 48 mpg when in a good state of tune. I monitor the mileage and if it drops below 45 I know it needs some work (granted If I am on it hard all the time, 45 is fine).

Kenny
 
Bikes up to and including the manufacturer year 1979 had VM mechanical slide carbs. These carbs idle circuits were set by adjusting the fuel pilot needles and the airscrews for mixture. Starting in 1980, bikes came with CV carbs (constant velocity). CV carbs also have a fuel pilot and airscrew, but that is not how they are adjusted. They are adjusted by a third screw called a mixture screw/throttle plate/butterfly. This third screw regulates the amount of an already determined mixture that goes into the intake tubes in the idle range which is exactly what the earlier carbs (VM) did with the two carb screws. (regulate the idle mixture) They do the same thing, but they dont work in quite the same way, and the parts you adjust ARE different.
Whenever someone is speaking of adjusting a carb, my first question is always, VM, or CV.
Pilots jets are not adjustable in either style carb. Fuel pilot screws/needles are. (not to be confused with slide needles......something entirely different)

Earl


Detman101 said:
Pilot jets? I thought the pilot jets were inside the bowl under those rubber plugs?
Do you mean the ones on the outside of the carb? I thought those were the mixture screws?
We need to come to some consolidation/standardization on what screw is called what...
No wonder I can't get any of my carb settings right...everyone is talking different things with the same terminology.
This sucks... :(

Dm of mD
Click to expand...
 
My 400 was getting 43 a few years ago. I haven't checked lately, I'm due for a quick internal inspection of the carbs and a sync. Carb boot o-rings only cost 4 bucks each here so I'm changing them too! :)

Steve
 
Sheesh Steve! My 1150E gets 43 mpg at 75 mph. :-) :-)
It only get 27 mpg at 145 though. :-)

Earl

srivett said:
My 400 was getting 43 a few years ago. I haven't checked lately, I'm due for a quick internal inspection of the carbs and a sync. Carb boot o-rings only cost 4 bucks each here so I'm changing them too! :)

Steve
Click to expand...
 
I'll have to get back to you on what I get at 145. :lol:

Steve
 
Re: Is 48 MPG Good For A 550?

Hoomgar said:
I tested my 550 and I am getting and average between 47 to 49 MPG out of it since I cleaned the carbs out and got it running right.

What is the average MPG expected out of a 550cc street bike?
Click to expand...
Sssssshhhhh!!!!! 8O .....Don't tell Alex ("Satchmo"). :wink:

BB
 
Pete's GS said:
The screws on the top of the intakes (usually under sealed plugs) on CV carbs are indeed called pilot jets. Don't ask. I've heard them called "mixture screws" and "air screws" too but according to R Riles at motorcyclecarbs.com they're actually pilot jets. They control the mixture from idle to about 1/4 throttle. When they're adjusted right you get a smooth running engine and a nice quiet clutch. I think on Mikuni VM carbs (slide throttle) the pilot jet is inside the carb body.
Click to expand...

It sounds like someone somewhwere has something crossed up. A jet is an orefice inside a carburetor that has fuel drawn up through it by pressure difference. There is no such thing (to my knowledge) as an 'adjustable jet'. If you don't like what your jet is doing you unscrew it from the carb and put a different one it. That is if it's not a fixed jet, which means it can't be removed from the carb. You do have a pilont 'circuit' in your carbs, which includes a pilot jet INSIDE the carb, and a pilot air screw OUTSIDE the carb. This is the terminology used in every manual in my house including including carb manuals for SU, Rochester carbs, and one covering motorcycle carbs. I think it's pretty standard terminology and it's what I go by.
 
Hoomgar said:
So it sounds like I am right on then. Cool :)

Thx guys...
Click to expand...

Mark

lancaster counrty PA. has lots of hills turn and stops. you are getting superior gas mileage . Of course the fact that you are only 4'3" tall and weigh 80 pounds helps a bit.
 
that's pretty good gas mileage. i get about 30-35 city driving...and about 40-42 on the back roads or longer rides. my setup isn't exactly stock, either.

~AOD
 
Hmm...I had better not say that my modified GS1000 gets 20 kpl on trips and 16 or more around town. This is going at speeds where I don't get caught doing the wrong thing....
 
For us Americans, thats 47 hwy/37 city MPG..

Nice! Wish mine was that good, and my GS1000 is stock!
 
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