#4 Carb Throttle Butterfly

[canwi]

Hi everyone.

I am trying to Synch my CBX 1979 1000 carbs yet not getting any vacume from #4 carb. Tried everything with no progress. Again have taken the carbs off the bike and loosened the front and read carb brackets, to no avail.

I have noticed that #4 throttle butterfly does not close off any of the 3 air bypass holes. While all the other throttle butterflies close them off with turning the synch screws nothing will close #4. Is it possible that #4 butterfly is worn at the bottom and top, as I can see daylight at the top of the butterfly when all the other carbs are completely closed. I know this is the factory setting that all other carb synch takes place from. Yet surely #4 should be covering all but 1 of the bypass holes?

Appreciate all feedback to finally be able to synch these carbs.

Canwi.

[tevan]

Have you tried to back off all sych screws so they will open up some and not be closed and then the #4 should close? Then when the #4 closes adjust them to close. Also have you got the idle adjustment screw backed off some?

[canwi]

Hello.

Yes Throttle backed off all the way. Loosened the carb brackets yet to no avail. #4 still open showing the By-Pass hole and 2 progression holes (3 open in total). SO still no vacume reading from #4. The 5 other butterflies are looking shiny, yet #4 is looking older. Is it possible that it may be worn as I see light at the top also, when all others are closed off.

[daves79x]

One or more of the others are holding #4 open. You have to do as Terry said - back off#5 and that will back off #6, then back off #3 and 4 should close. Now it may not be centered quite right, and that's a different matter, but you won't know until you back the others off. Then you work out from #4 to 5 and 6, then go to 3,2,1. #4 is the base you start from.

Dave