Results 1 to 3 of 3
  1. #1
    CB750 New Member GPER's Avatar
    Join Date
    Apr 2019
    Location
    Northwest Connecticut
    Posts
    2

    Leaking Carburators

    Hi All,
    I'm a newbie and this is my first post on the forum. What a tremendous resource for the CB750 fanatics. I owned a K-2 back in 1973 when I was much much younger and on a whim looked a a fresh restoration of a 1971 CB750K1. After starting it I immediately traveled back almost 50 years, so I purchased it. However I digress. Once the weather broke, I took it out and at first she ran fine, but I noticed some a sluggish throttle at 3000 rps. I only put on 5-6 miles so I brought back and pulled the plugs. They were black and sooty........clearly to rich. I am running Sunoco 100 ethenol-free gas but I am sure that's not the issue. I stuck in some new plugs and new OEM filter and took her out this evening. Same result black and sooty plugs and she ran worse stalling a couple of times. Interesting I forgot to turn of the gas petcock and noticed all 4 carbs were leaking thru the over flow tubes. I need some collective wisdom and direction. Where do I start? Did I say this was a fresh restoration!

  2. #2
    Moderator dirtdigger's Avatar
    Join Date
    Feb 2012
    Location
    Black Hawk SD
    Posts
    2,805
    I would start by pulling the carbs and cleaning them out and probably put some new float needles, and you can see what it has for pilot and main jets and see what position the clip in the needle is in . leaking in the overflow is a float and or needle problem. The early carbs had all metal needles with no rubber tip so any little piece of dirt causes them to leak.

    I would go through everything. New points and condensors, set timing/dwell, adjust timing chain, adjust valves...would be good to do a compression test at this time so you know if the engine is healthy enough to continue with. Carb sync ones cleaned out.

    Start with the basics

  3. #3
    CB750 New Member GPER's Avatar
    Join Date
    Apr 2019
    Location
    Northwest Connecticut
    Posts
    2
    Quote Originally Posted by dirtdigger View Post
    I would start by pulling the carbs and cleaning them out and probably put some new float needles, and you can see what it has for pilot and main jets and see what position the clip in the needle is in . leaking in the overflow is a float and or needle problem. The early carbs had all metal needles with no rubber tip so any little piece of dirt causes them to leak.

    I would go through everything. New points and condensors, set timing/dwell, adjust timing chain, adjust valves...would be good to do a compression test at this time so you know if the engine is healthy enough to continue with. Carb sync ones cleaned out.

    Start with the basics

    Thank you sir.

Similar Threads

  1. Carburetor leaking
    By blakieboy in forum The CB750 Garage
    Replies: 0
    Last Post: 09-17-2018, 09:41 PM
  2. Gas leaking
    By Kuntryboy in forum Carburetors / Fuel
    Replies: 4
    Last Post: 10-06-2016, 06:49 PM
  3. leaking carburetor
    By Steve L in forum Carburetors / Fuel
    Replies: 2
    Last Post: 07-14-2014, 09:32 AM
  4. Cams leaking?
    By jacksondee in forum The CB750 Garage
    Replies: 11
    Last Post: 03-13-2014, 11:40 PM
  5. leaking oil need help.
    By jeremyb724 in forum The CB750 Garage
    Replies: 5
    Last Post: 10-28-2013, 08:40 AM

Posting Permissions

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