78 cb550k 605cc bore misfire...
Close

78 cb550k 605cc bore misfire...

This is a discussion on 78 cb550k 605cc bore misfire... within the Technical forums, part of the Caferacer.net Forums category; so i had a little issue with a strong misfire that would lead to stalling out after. it seemed like it would only happen when ...

Page 1 of 4 123 ... LastLast
Results 1 to 10 of 33
  1. #1
    Member photoputz83's Avatar
    Join Date
    Aug 2011
    Location
    eau claire, wisconsin, USA.
    Posts
    51

    78 cb550k 605cc bore misfire...

    so i had a little issue with a strong misfire that would lead to stalling out after. it seemed like it would only happen when the engine was hot or when i hit high revs while riding and then let off. there were a few occasions where i would try to start it again and then the battery would almost be completely drained. i ended up going all out replacing the coils, the ignition (dyna s), and eventuallly the entire engine as i wanted to have more spare parts on hand or to rebuild so when one engine messes up or needs a rebuild i would have one to drop in. well after all of this was done it seems like the misfire hasnt got any better. i pretty much chainged everything but the carbs which have been cleaned, the wire harness, and the rectifier. would the rectifier cause a misfire for any reason. im looking for any ideas as to what may cause this to happen. the riding season is almost at its end so any help would be halful at this point.

  2. #2
    Senior Member crazypj's Avatar
    Join Date
    Nov 2008
    Location
    Altamonte Springs, Fl. USA, Bridgend, South Wales, U.K.
    Posts
    3,437
    Fuel tank cap vent
    I dabble in rocket science, when I\'m not picking my nose
    The other night I gave my girlfriend an orgasm, but, she spat it back at me

    'you can take my word for it or argue until you find out I'm right'

  3. #3
    Member photoputz83's Avatar
    Join Date
    Aug 2011
    Location
    eau claire, wisconsin, USA.
    Posts
    51
    actually on the 78 there is a door that covers the cap. it isnt out in the open like the 550s from the previous years. there is a hole in the tank under that door next to the gas cap and it is clear at this point.

  4. Remove Advertisements
    CafeRacer.net
    Advertisements
     

  5. #4
    Senior Member Geeto67's Avatar
    Join Date
    Oct 2005
    Location
    Columbus, Ohio
    Posts
    23,274
    quote:Originally posted by photoputz83

    actually on the 78 there is a door that covers the cap. it isnt out in the open like the 550s from the previous years. there is a hole in the tank under that door next to the gas cap and it is clear at this point.
    yeah? really? you are confusing the fuel door drain for the tank cap vent?

    1) the fuel door doesn't seal airtight over the cap. Least it shouldn't

    2) your cap should still have a vent in it otherwise it is a sealed container.

    3) learn the parts of fuel tank and how it works.
    Ever tried. Ever failed. No matter. Try Again. Fail again. Fail better.
    - Samuel Beckett
    A tool is just an opportunity with a handle
    - Kevin Kelly

  6. #5
    Senior Member jaguar's Avatar
    Join Date
    Dec 2005
    Location
    Albany NY
    Posts
    10,437
    when you say miss fire what do you mean?
    I am Derby\'s Bitch


    Some times things come around that are so singularly inept it gives you a whole new appreciation for the ept

  7. #6
    Member photoputz83's Avatar
    Join Date
    Aug 2011
    Location
    eau claire, wisconsin, USA.
    Posts
    51
    the drained battery and misfire would not be an issue with the fuel or supply. i am getting enough fuel to the engine as i am running a little rich at idle and almost perfect at 3/4 to full...
    quote:Originally posted by Geeto67

    quote:Originally posted by photoputz83

    actually on the 78 there is a door that covers the cap. it isnt out in the open like the 550s from the previous years. there is a hole in the tank under that door next to the gas cap and it is clear at this point.
    yeah? really? you are confusing the fuel door drain for the tank cap vent?

    1) the fuel door doesn't seal airtight over the cap. Least it shouldn't

    2) your cap should still have a vent in it otherwise it is a sealed container.

    3) learn the parts of fuel tank and how it works.

  8. #7
    Member photoputz83's Avatar
    Join Date
    Aug 2011
    Location
    eau claire, wisconsin, USA.
    Posts
    51
    the engine runs fine in normal conditions or atleast it did. the misfire from what i am feeling is a shudder and then refusal to spark / ignite the gas. the it seems to start happening when i push the bike pretty hard, and after i let off is when things all start to go downhill. i know it isnt the coils, or the ignition as it is timed correctly, and both are new. i do however suspect something electrical which is why i was wondering about the rectifier.
    quote:Originally posted by jaguar

    when you say miss fire what do you mean?

  9. #8
    Member photoputz83's Avatar
    Join Date
    Aug 2011
    Location
    eau claire, wisconsin, USA.
    Posts
    51
    oh and i ran it with the gas cap off and it did the same thing.
    quote:Originally posted by Geeto67

    quote:Originally posted by photoputz83

    actually on the 78 there is a door that covers the cap. it isnt out in the open like the 550s from the previous years. there is a hole in the tank under that door next to the gas cap and it is clear at this point.
    yeah? really? you are confusing the fuel door drain for the tank cap vent?

    1) the fuel door doesn't seal airtight over the cap. Least it shouldn't

    2) your cap should still have a vent in it otherwise it is a sealed container.

    3) learn the parts of fuel tank and how it works.

  10. #9
    Senior Member mlinder's Avatar
    Join Date
    Nov 2008
    Location
    Your Moms House, USA
    Posts
    2,952
    Connect multimeter to battery terminals.
    Tape multimeter to middle of handlebars.
    Go ride, check voltage when misfire happens.
    http://quiterandom.hubpages.com/hub/...sic-motorcycle How to buy a used bike
    http://quiterandom.hubpages.com/hub/...the-Cafe-Racer How to build a cafe racer

    It's like a Machiavellian 4-volume trilogy based on Hamlet senza misura with an ego-maniacal downs syndrome kid reading from a Rube Goldeberg-esque kindle.

  11. #10
    Senior Member Geeto67's Avatar
    Join Date
    Oct 2005
    Location
    Columbus, Ohio
    Posts
    23,274
    Not saying your misfire has to do with the vent, just saying you identified and checked the wrong parts.

    The cap has a vent so your petcock can feed fuel without creating a pressure problem. The gas door is there to prevent the bike from dousing you in gasoline in case of a front end accident. The hole near the gas cap is just in case you spill fuel filling the bike up or you ride through a rain storm and need a place for the water that collects under the door to drain.

    Misfires are caused by two things fuel or spark. Running it with no gas cap eliminates it being a vent problem.

    Have you checked your spark advance mechanism? Might be hanging up.


    Ever tried. Ever failed. No matter. Try Again. Fail again. Fail better.
    - Samuel Beckett
    A tool is just an opportunity with a handle
    - Kevin Kelly

Page 1 of 4 123 ... 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
  •  

Similar Threads

  1. Big bore kitYamaha xs750/ 900cc big bore kit
    By fffast in forum Parts For Sale
    Replies: 0
    Last Post: 09-23-2012, 07:15 PM
  2. 605cc big bore kit Henry Abe
    By Pain in forum Parts For Sale
    Replies: 0
    Last Post: 03-01-2011, 08:11 AM
  3. 78 cb550K Four
    By 3rd Degree in forum Bikes For Sale
    Replies: 3
    Last Post: 03-16-2010, 11:37 AM
  4. cb500f 605cc big bore kit - technical help
    By xs650joe in forum Technical
    Replies: 2
    Last Post: 01-20-2008, 10:16 PM
  5. cb550k
    By cbr900turbo in forum Project Builds
    Replies: 3
    Last Post: 08-04-2007, 11:08 AM

Search tags for this page

605cc big bore kit

,

cb550k misfire

Click on a term to search for related topics.