VF500F - 1984 Carb Specs - Main and Slow Jets, Emulsion Tubes and Jet Needles

Discussion in '1st & 2nd Generation 1983-1989' started by invisible cities, Oct 18, 2010.

  1. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    Hi All,

    I've been working on a carb rebuild, on my '84 VF500F US model, and thought I would post my findings.

    The main jets are sized front to back (#102F/#105R) as is often posted.

    What is interesting to note, on the set I have, is the 'criss-cross' pattern of the needle jets and the emulsion tubes.

    This does not match FSM...

    [​IMG]

    Cylinder numbering:

    [​IMG]

    [​IMG]

    Close up of the No. 1 and No. 4 main jet emulsion tube:

    [​IMG]

    Close up of the No. 2 and No. 3 main jet emulsion tube:

    [​IMG]

    I am not sure why this set is like this but I have seen previous posts regarding the 'criss-cross' set-up - i.e that the jet needles and main jet emulsion tubes are not paired front to back - rather - they are paired from the two 'middle' throttle bodies to the two 'outside' throttle bodies.

    I would be curious to see what other owners have found for the '84 as well as the other years.

    Thx!
     
    Last edited: Oct 19, 2010
  2. mrich12000

    mrich12000 New Member

    Joined:
    May 10, 2009
    Messages:
    269
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Calgary, Alberta.Canada
    Map
    Take it as one day the assembler had gone that early night to a local socki club and was still under the influence, had put the line of carbs together improperly.Now if you want to clean that puppy, Get 8 liters of Pine-Sol, one rubbermaid bini strip and soak in the Pine-Sol, for 8-14 hours . It will come out of the bath sparkling clean wash off with water and without the booze assemble.

    Hope someone hear can help with the jet placement..Mike..
     
  3. blitzas

    blitzas New Member

    Joined:
    Mar 21, 2010
    Messages:
    172
    Likes Received:
    0
    Trophy Points:
    0
    Cylinder numbering is:

    Front
    Left 2 Right 4

    Rear
    Left 1 Right 3
     
  4. JamieDaugherty

    JamieDaugherty New Member

    Country:
    United States
    Joined:
    Aug 26, 2006
    Messages:
    2,386
    Likes Received:
    16
    Trophy Points:
    38
    Location:
    Fort Wayne, IN
    Map
    The parts do not make complete sense. I can tell you that the needles do not follow the emulsion tubes. It's weird.


    [​IMG]
     
  5. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    Thank you for the post.

    I'm not seeing this on the set I have though - on this set the emulsion tubes follow the needle jets:

    [​IMG]

    Has anyone encountered this before?

    I doubt very much that this set was fiddled with - though after 25 years you never know...
     
  6. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    Thank you for the post.

    I have added this for clarification.
     
  7. JamieDaugherty

    JamieDaugherty New Member

    Country:
    United States
    Joined:
    Aug 26, 2006
    Messages:
    2,386
    Likes Received:
    16
    Trophy Points:
    38
    Location:
    Fort Wayne, IN
    Map
    Exactly. That's why I agree that yours are not correct. On all of the VF500 carbs I've worked on they were different - the needles and emulsion tubes were all mixed up. Pretty much just like what the manual states. Remember, the Honda manual is gospel!
     
  8. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    Okay thanks.

    Regarding the jet needles, the FSM I have (1984 US) notes:

    Front: 2VA
    Rear: 2VD

    Gospel as well?
     
  9. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    Here is a copy of the FSM (1984 US) noting the jet needles in a front | rear orientation:

    [​IMG]
     
    Last edited: Oct 19, 2010
  10. Michael E

    Michael E New Member

    Joined:
    Mar 12, 2010
    Messages:
    532
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Ottawa, Ontario
    Map
    That's just weird. I'd have to think that the assembler got distracted and messed up or someone had it apart and messed up. It does not make any sense like that.
     
  11. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    It could be that someone had them apart...they are off of a bike that only has 5,800 miles on the clock but after 25 years it could be someone decided to make a home brew along the way.

    I am still puzzled though.

    Post 4 notes that the needles do not follow the emulsion tubes and that the emulsion tubes are oriented front | back.

    The FSM notes that the jet needles are oriented front | back.

    If the FSM is correct and the emulsion tubes are oriented front | back wouldn't the jet needles follow the emulsion tubes?

    Thx!
     
  12. Michael E

    Michael E New Member

    Joined:
    Mar 12, 2010
    Messages:
    532
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Ottawa, Ontario
    Map
    How do your plugs look? Were they pretty even?
     
  13. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    The photo in post #4 shows the emulsion tubes in a front | back relationship.

    The FSM (post #9) shows the needle jets in a front | back relationship.

    Post #4 also notes that the 'needles do not follow the emulsion tubes'. Not sure how this can be correct.

    Am I missing something?

    I've added a sketch to help clarify.

    [​IMG]

    IF the emulsion tubes do not follow the needle jets (per post #4) - then either the photo is mislabeled or the FSM is incorrect.

    Any thoughts would be most appreciated.

    Thx!
     
  14. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    Also, from the parts diagram - this notes the jet needles and the emulsion tubes in a front | back relationship.

    [​IMG]
     
    Last edited: Dec 10, 2010
  15. jmcallis

    jmcallis New Member

    Joined:
    Dec 8, 2010
    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Portland/The Dalles
    How are the jet needles different? Length, taper, diameter?
     
  16. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    The jet needles differ in their taper.
     
  17. jmcallis

    jmcallis New Member

    Joined:
    Dec 8, 2010
    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Portland/The Dalles
    I am aware that the stock needles are not adjustable, compared to an adjustable needle how important is the distance #4, is the distance of #3 arbitrary. The whole diaphragm moves so why is the distance for #4 not fixed, why does it move at all? What are the dimensions of #1 and #2 for the stock needles? I imagine 2VA and 2VD stand for something how are those read or decoded or are they just part numbers with no meaning.
    Hopefully the picture shows up or this will not make a lot of sense.
    [​IMG]
     
  18. invisible cities

    invisible cities New Member

    Country:
    United States
    Joined:
    Oct 20, 2009
    Messages:
    2,258
    Likes Received:
    0
    Trophy Points:
    36
    Location:
    new york
    Map
    The code stamped on the jet needle is not arbitrary - it is a Honda part after all ;-)

    This code references the taper on the jet needle. The jet needles are paired with specific emulsion tubes in a front and rear relationship.

    On this note, the front carburetors (2&4) on a VF tend to run rich based on being mounted horizontally and as such these carburetors receive smaller main jets and a jet needle with a milder angle of taper paired with a specific pattern in the emulsion tube which controls the air/fuel mix.
     
  19. Michael E

    Michael E New Member

    Joined:
    Mar 12, 2010
    Messages:
    532
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Ottawa, Ontario
    Map
    Everything to the left of the 2 mark is irrelevent as long as it provides enough force to seat the needle into the slide. The needle seats/mates with the slide at the right edge of #2 in your drawing. It is everything to the right of this right score mark, i.e. #1, that matters and determines the needle's relationship with the jets in the throat of the carb. The greater the length of #1 the richer, the shorter the length of #1 the leaner.
     
  20. GreyVF750F

    GreyVF750F Member

    Country:
    United States
    Joined:
    Jul 15, 2008
    Messages:
    3,268
    Likes Received:
    2
    Trophy Points:
    51
    Location:
    West of Cleveland Ohio
    Map
    You can shim the non-c-clip needles with .020 thick washers under #2. I believe the c-clip spacing is about .040. I use .020 washers for fine tuning. I think you can only get a total of 4-.020 washers before the twist cap lock won't go on. Michael is right about length but don't forget the type of taper and diameter of the needle does the same. You can also fine tune by plugging or adding holes to the emulsion tubes. The end away from the jet is low to mid range the holes closet to jet is for upper rpms. Thing about emulsions tubes are, if you screw up just solder in the hole and re-drill different size or height location.

    Actually the needles should be paired with jet size and type. I guess you could throw the emulsion tubes in that fray. Between the three you can do a lot of tuning.
     
    Last edited: Dec 11, 2010
Related Topics

Share This Page