• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

1980 GS750E - CV Carb Idle Adjustment Question

  • Thread starter Thread starter dcb
  • Start date Start date
D

dcb

Guest
I have a 1980 GS750E with the CV carbs. I have noticed there are only three adjustments to synchronize the carbs. Is there any way to adjust all four? If not which carb can not be adjusted?

Thanks,
David
1980 GS750E
1968 YR2
 
Number three cannot be adjusted, you must adjust all carbs to that one. That is the carb that your throttle cable is attached to.

Scud
 
David, the title to your post makes me wonder what you are trying to accomplish. The idle adjustment is done by opening the vacuum slides via the idle adjust knob. The three screws you mention are used to ensure that these same slides open at the same time by making sure the throttle butterflies open simultaneously. They don't control idle speed directly.

OK... if your question was about the function of the sync screws, all four carbs ARE adjusted using these three screws. First, loosen all three locknuts. There is a special tool to do this while the carbs are on the bike. It is made by Motion Pro and is essentially a long tube with an 8mm socket on the end with a flat blade screwdriver in the middle. It also allows you to tighten the locknuts with the carbs on the bike by holding the screw while tightening.

The way you adjust the synchronization (getting slides to open simulaneously) is hook up a manometer (vacuum gauges w/four hoses). With the bike warmed and idling, FIRST use a long screwdriver and adjust the screw between #1 and #2 carbs so that the mercury (vacuum) level on these two carbs are the same. Then you adjust the #3 screw between carbs #3 & #4 so they are the same level vacuum/mercury. Last, you adjust the middle adjustment screw to level 1&2 and 3&4. When you have them all at the same level, shut the bike off. Use the special tool I noted OR remove the carbs and carefully tighten the locknuts on the adjuster screws while holding those screws with a screwdriver so they don't turn any as you do your tightening.
 
I need to get a mercury refill for my manometer so until then I am just trying to get it close. I will look into that Motion Pro tool, it sounds like one of those tools that can save you a lot of frustration.

I am also thinking about getting a Colortune, any thoughts there?

Thanks,
David
1980 GS750E
1968 YR2
 
You must log in or register to reply here.
Back
Top