Page 3 of 3 FirstFirst 123
Results 41 to 57 of 57
  1. #41
    CB750 Guru amc49's Avatar
    Join Date
    Sep 2015
    Location
    Fort Worth TX.
    Posts
    2,181
    I gave there, no need to get the last stab. Where's all your talk of getting along with people now? Thanks only and I would have been gone.

  2. #42
    Moderator dirtdigger's Avatar
    Join Date
    Feb 2012
    Location
    Black Hawk SD
    Posts
    2,650
    No ones making you come back all the time. You have no idea how many complain about you on this forum to the moderators. I'm tired of talking people into staying and contributing to the forum because of something you said to them. No matter how much I preach you dont get it. Your the only one that people have a problem with, maybe that should tell you something. Just sayin.

  3. #43
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Update: relay has been installed so Iíve got battery voltage at the coils. Float valves will arrive today so Iíll set those first and see how it runs, then check the lift with the dial indicator.

  4. #44
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    And Iíll just say, itís true amc your responses werenít exactly inviting for a first time poster. The ďyouíre wrong and if you donít listen to me youíre also stupidĒ sort of stuff isnít what people are looking for when theyíre inexperienced with these bikes and need help.

  5. #45
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Alright, itíll hold a steady idle and sounds good at 1100. Still canít use the choke to start or warm it up or it sounds like itís flooding, all four plugs are a very light tan so bumping the idle jets down to 38s and trying the choke doesnít seem like a great idea.

    Did the clear tube fuel level check and got 3mm below the mating surface in 3&4 and 7mm in 1&2. I triple checked all the float heights before installing and theyíre the same, seems unlikely that itís a float height problem innthat the carbs on the same fuel inlet are the same level but I can adjust the heights on 1&2 if no one has a different recommendation.

    Ideas?

  6. #46
    Moderator dirtdigger's Avatar
    Join Date
    Feb 2012
    Location
    Black Hawk SD
    Posts
    2,650
    Ive never used the clear tube, I always just use my honda float gauge. If you do indeed have different levels then that is a problem. You are checking on the center stand not the side stand correct? To me your numbers sound really high.

  7. #47
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Quote Originally Posted by dirtdigger View Post
    Ive never used the clear tube, I always just use my honda float gauge. If you do indeed have different levels then that is a problem. You are checking on the center stand not the side stand correct? To me your numbers sound really high.
    Sorry, it wasnít a float height problem. The fuel line to 1&2 went uphill. Once I routed it correctly I see all fuel levels even and at the correct height. Dealing with carb boot leaks at the head now. New boots, 46 and 44mm clamps donít seal it well enough. I canít even crank the 44mm all the way down so Iím at a loss. No leaks previously so the spigots on the heads are sealed.

  8. #48
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Just got 0.355Ē on the inlet side and 0.311Ē on the outlet. Getting the dial indicator set perfectly in line is harder than I thought and the slot for a flathead screwdriver on the top of the tappet makes it worse.

  9. #49
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Iíll check them again tomorrow night after I havenít been working in the garage all day

  10. #50
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Okay tried a flat tip (duh.), got 0.315 inlet and 0.312 outlet. I donít know if the rocker arm geometry ends up reducing the lift at the tappets or increasing them, but these look really close to stock

  11. #51
    Moderator dirtdigger's Avatar
    Join Date
    Feb 2012
    Location
    Black Hawk SD
    Posts
    2,650
    The rocker ratio is 1.1 to 1....increasing lift at the valve.

  12. #52
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    So keeping in mind the fact that they donít move in a straight line, adding a curve to that measurement would increase it just slightly, but the fact that Iím using a flat edge to measure something that starts with one angle and ends with another (then barely reducing the movement), it should be real close to the numbers I have. Sound about right?

  13. #53
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Plugs all look good and it idles great! Choke still doesnít help but it warms up quickly. Iím not worried about the tappet adjustment after seeing those numbers. Thanks everyone.

  14. #54
    Moderator dirtdigger's Avatar
    Join Date
    Feb 2012
    Location
    Black Hawk SD
    Posts
    2,650
    I still dont get why your choke does work....putting the choke on once the engine is running should literally kill the engine....unless you have a huge vacuum leak. Maybe post some pictures of the choke plates open and closed, maybe can see something you are missing.

  15. #55
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    It does kill the engine if the engine is warm and I put the choke on. My problem is it doesnít act like a more modern choke in that it wonít start or idle choked when cold, but that seems to be a common problem with very early carbs. I verified no light was getting through at all when theyíre closed and they were raising in sync.

  16. #56
    Moderator dirtdigger's Avatar
    Join Date
    Feb 2012
    Location
    Black Hawk SD
    Posts
    2,650
    If these are the correct round top carbs for the 71 then there is not a fast warmup idle system on these. You have to increase the throttle setting manually to keep it running when cold. These are old school, the choke is just that a choke, all it does is restrict airflow to make the mixture rich it doesnt do anything to throttle position. More modern carbs open the throttle just a bit as the choke is put on to raise the rpm to compensate for the cold engine etc.

  17. #57
    CB750 Member wkong's Avatar
    Join Date
    Apr 2018
    Location
    Washington
    Posts
    29
    Yup, exactly what Iíve learned. Why I chose an early 70s bike with four carbs to be my first to try to rebuild Iíll never know. Probably should have had a running one next to it to see how it worked first. Oh well! Itís all good now

Page 3 of 3 FirstFirst 123

Similar Threads

  1. plugs fouling
    By untill62 in forum The CB750 Garage
    Replies: 37
    Last Post: 09-02-2018, 08:32 PM
  2. Carb issues / oil coming from spark plug
    By DildoMagic104 in forum The SOHC Garage (1969-1978)
    Replies: 4
    Last Post: 06-22-2017, 08:45 PM
  3. 1980 CB750K idle issues
    By powellskier in forum The DOHC Garage (1979-1983)
    Replies: 2
    Last Post: 05-27-2017, 08:05 PM
  4. lousy fouling plugs
    By untill62 in forum The SOHC Garage (1969-1978)
    Replies: 12
    Last Post: 07-09-2016, 04:43 PM
  5. Fouling plugs?...
    By Dpratt23 in forum The CB750 Garage
    Replies: 8
    Last Post: 09-20-2013, 08:00 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
  •