Base setting for carb sync? (long).

[mellowyellow#7933]

Started off well getting right bank lined up with homemade oil manometer. Barely touched one on left side & everything went downhill from there. One or another kept going over the top as soon as I would start up & levels kept rising. Didn't have time to notice one was sucking air into resevoir. After letting air escape several times from res (made one with 90 deg bend with threaded cap) & several hrs, couldn'get anywhere near sync on left bank. Turned all 6 screws in & backed out each 2 turns. At 4:00 am (started at 7:00 pm) called it a night & went back next day. Managed to get everything from going over the top or away from the bottom but nowhere near close on left side without affecting right side, bike running well.
Can anyone check theirs? Does it matter how many turns out as long as they're all the same to start?
I will check for leaking intake o-ring, but didn't see any evidence of residue around any of them.
Sorry for the long post. TIA

[Ricky-D]

One thing you should do prior to attempting to synchronize the carburetors is to lubricate all the junctions and rotating springs and parts screws included so that you get a true reaction from when you try adjusting the carburetors.

An outside fan is absolutely necessary to keep the radiator fan from cycling.

Continuing to adjust the idle is an important step while synchronizing.

As you get every carburetor closer to the baseline the adjustment becomes more sensitive on all the carburetors and so less turning is required.

You must devise a method to keep track of what you are doing regarding turning the adjustment screws since some screws turn the carburetor adjustment and others turn the connector rods.

Only experience will result is satisfactory results and I went through hell the first few times I synchronized the carburetors.  Yet still I am very apprehensive in going back in remembering what I've gone through.  It can be very, very frustrating.

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[Madmike]

remember that you are dealing with oil as a fluid in your homemade manometer rather than mercury and the differences in the relative gravity between the two fluids.  Hg is about 13.5, water is 1.0 and the oil will be somewhere around .8 - the spec allows 1.6" of Hg.

[John U.]

I guess you've found this out already but my problems with the home made manometer all had to do with air (vacume) leaks. A leak anywhere in the system will allow the oil to rise to the top of the vacume lines and destroy the accuracy of the rig.

[Robert]

2 things, You have to loosen off all connecting linkages so that one carb turns independently of the one next to it and cylinder 3 is the base. If you dont loosen the linkages you are really not balancing the carbs. The linkage will give a bit but not really doing the job, that's why when you adjust one the others are affected, they shouldn't be. When you get them synced at idle I would also check to see if they are on at around 1500 to 2000 rpm when you tighten up the linkages again.

[Ricky-D]

2 things, You have to loosen off all connecting linkages so that one carb turns independently of the one next to it and cylinder 3 is the base. If you dont loosen the linkages you are really not balancing the carbs. The linkage will give a bit but not really doing the job, that's why when you adjust one the others are affected, they shouldn't be. When you get them synced at idle I would also check to see if they are on at around 1500 to 2000 rpm when you tighten up the linkages again.

It would be a great help if you could explain in more detail what you are proposing and pictures will add a greater dimension to what you are explaining Robert!

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[Joe Hummer]

To me...it sounds like you are trying to sync the carbs using the Air Mixture screws instead of the Carb Sync screws.  The carb sync screws are located under the choke rail covers and there are only 5 of them.  The #3 carb is your base.  Check it first and set the others to it. 

Make sure you are adjusting the right things and go from there. 

Joe

[Robert]

  The bottom pic is of the idle adjustment screw on #3 cylinder this is adjusted to get base idle which is already where you are starting out at. This will adjust all the carbs. You will only have 2 screws like in the following pics on the rt side as sitting on the bike because you are only adjusting the 2 carbs to sync with #3.
  The top pic shows the adjustment screw with the throttle slightly open showing the spring and the adjustment screw and they should all wind up to approx  the same spacing. If the spring is missing or the adjustment is way far off from carb to carb there is a problem.
  The middle pic shows the adjustment screw after you take off the cover between the carbs. You can just see the end of the linkage that goes over to the other carbs attached to the rt of the screw that adjusts the carb.
Hope this helps