Fuel Consumption
Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 24
Like Tree2Likes

Thread: Fuel Consumption

  1. #1
    Senior Member Polish's Avatar
    Join Date
    Oct 2017
    Location
    Sudbury, Ontario
    Posts
    500

    Fuel Consumption

    Hello guys, it's been 2 tank of gas on my CB 400T so far in town and I feel my fuel consumption is right to the roof. I get 27.14 MPG and spec online says I should get 48.5 MPG. Stock air box, carbs and exhaust. What is going on?
    JL
    1979 CB 400 T (Cafe Racer)

  2. #2
    Senior Member Polish's Avatar
    Join Date
    Oct 2017
    Location
    Sudbury, Ontario
    Posts
    500
    And that's before I get the reserve......
    JL
    1979 CB 400 T (Cafe Racer)

  3. #3
    Senior Member JamesPal's Avatar
    Join Date
    Sep 2009
    Location
    Bellevue, Washington
    Posts
    3,406
    I would think it should do better than that, but if you are running flat out on the track it might be OK. I get around 140 miles out of a tank and then put 2 1/2 gallons or so in it. I usually don't run it down to the reserve.
    Jim Palmer
    '85 GL1200I (Garage Find)
    '81 GL1100 STD (Project)
    CB450 K5 Done
    https://www.hondatwins.net/forums/1-...s-cb450k5.html
    What I learned from Restoring a CB450 K5
    Watch Mike and Jim Take on Mt Erie Washington State
    "If everything seems under control you are not going fast enough" Mario Andretti...

  4. Remove Advertisements
    HondaTwins.net
    Advertisements
     

  5. #4
    Senior Member Polish's Avatar
    Join Date
    Oct 2017
    Location
    Sudbury, Ontario
    Posts
    500
    Also, I'm putting the bike on the side stand, therefore, missing the top portion of the tank. I'll keep trying different things and see. Thx
    JL
    1979 CB 400 T (Cafe Racer)

  6. #5
    Senior Member 80cb400t's Avatar
    Join Date
    Sep 2017
    Location
    BC
    Posts
    741
    I get around 50, also stock hardware, I have replaced all rubber in the carbs and done the coil upgrade. Is your gearing changed significantly?
    When was the last time you pulled your tank filter? When I first got my bike I'd run out of gas early and be really confused, turned out my filter was clogged except for one or two of the very top strips.
    1980 CB400T - 1 running, 1 parts bike
    1965 CB160 - 1 kind of running, 1 parts bike

  7. #6
    Super Moderator longdistancerider's Avatar
    Join Date
    Oct 2011
    Location
    Vancouver Washington (text 408-239-9580)
    Posts
    22,175
    Everything makes a difference. Tire pressure, condition of the chain and sprockets, bearings, brake drag, compression, valve adjustment, timing advance, spark quality, spark plugs, mixture adjustment, float level, jets, vacuum leaks, etc. Even riding style and shifting patterns make a difference.
    27 mpg is pretty bad, less than 40 is not good. So it's time to go thru each and every piece to confirm, set, adjust or replace everything to spec.
    fxray likes this.
    Jim O'Brien
    1979 CM400T "road bike" modified for travelling
    1978 CB400T1 restored
    1972 CL350 nuts and bolts restore in progress


    https://www.hondatwins.net/forums/22...d-attempt.html and https://www.hondatwins.net/forums/1-...r-attempt.html
    Road Trip https://www.hondatwins.net/forums/11...here-i-go.html or "where's Jim now?"
    Member Map https://www.hondatwins.net/forums/dcMembermap.php

  8. #7
    Senior Member Polish's Avatar
    Join Date
    Oct 2017
    Location
    Sudbury, Ontario
    Posts
    500
    Thx

    Fuel filter is new, carbs rebuilt and stock, floats adjusted, valves adjusted as well, no brake drag, new carb boots, air filter is new, chain and sprocket due probably next year. Tires installed by LBS, so assuming pressure is ok. New plugs and light brown colour, so not too rich. Pilot screw is 1 1/2 turns out. I didn't think there was any timing advancement since there is a key for the rotor to go in. What am I missing?
    JL
    1979 CB 400 T (Cafe Racer)

  9. #8
    Senior Member Polish's Avatar
    Join Date
    Oct 2017
    Location
    Sudbury, Ontario
    Posts
    500
    New wheel bearings as well. Would have to check compression again.
    JL
    1979 CB 400 T (Cafe Racer)

  10. #9
    Senior Member 80cb400t's Avatar
    Join Date
    Sep 2017
    Location
    BC
    Posts
    741
    Checking tire pressure yourself regularly is a great habit to get into. After I installed my new tires they lost a couple psi each night for a few days then stabilized. On a bike you've only got two, and at best you're riding on two packs of cards, one for each tire. So for me, whatever Honda decided those tires should be at that is where mine will stay and I will check as often as I remember.
    Last edited by 80cb400t; 06-30-2019 at 09:12 PM.
    1980 CB400T - 1 running, 1 parts bike
    1965 CB160 - 1 kind of running, 1 parts bike

  11. #10
    Supporting Member David Babbitt's Avatar
    Join Date
    Jun 2011
    Location
    Renton, WA
    Posts
    262
    47 mpg, freeway driving on a 1974 CL450K6 with 97k miles.

Page 1 of 3 1 2 3 LastLast

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •