The International CBX Owners Association

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.

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?

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.

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