The International CBX Owners Association

Wet test with an auxiliary fuel tank using a pre-maid T with hoses. Prop them at an appropriate angle. Put them in an aluminum baking pan on the very outside chance they leak. Bench syncing should be done referencing the very forward of the three holes in the carb throat only. Proper idle speed is with just the very smallest amount of that hole showing. Make them all match #4, when it's set to that spec. Beware that any other throttle plate closed more than #4 will hold them all up.

Dave

Thanks Dave. I will follow the procedure. I did use the last hole as reference. Cool advice on setting up idle

She's alive again! Finally got Mike Nixon's rebuilt carb bank installed on my '79 (that started this thread) and although I've only been around the patch, it runs very well. And no leaks. Quite a project - I could do it again much faster, but I pray I'll never have to. Nixon's videos and install notes were a godsend and Nixon is a god. This forum was a big help too. THANKS!!!

- Mark

Had my '79 CBX for 15 years. Parked for awhile and back on the road 3 years ago. Rode about 5000 Km (Canada) per year. Between carb cleaning from sitting for a month or so and leaks I've pulled the carbs off 8 times. Takes an hour and 10 minutes to get them off. With the heat gun and grease they seem to go on easy enough. I looked at the o-ring carb separation fun and games and just manoeuvred some Seal All around the connecting tube .No more leaks. Temporary fix but I just wanted to ride. I've heard about starting problems but with this bike I give it full choke ,don't touch the throttle and hit the starter and it fires right up. Cold blooded. Needs to warm up but runs fine. Bench synced carbs but I'm sure it not good enough. Looking for proper sync tool as mine won't work on the Honda.
Jerry

"Cold blooded" usually means lean. When I enlarge the idle jets to .038mm and 2 turns out on the mixture screws, that problem goes away.
Proper synchronization is necessary to insure that one carburetor isn't "leading" the others.
Exacting bench sync isn't always correct. Must be done on THAT running motor, not someone else's. Valve sealing condition, overlap, any minute vacuum leak, etc. will alter sync.

CBX-tras wrote: ↑

Wed Sep 30, 2020 8:02 am

"Cold blooded" usually means lean. When I enlarge the idle jets to .038mm and 2 turns out on the mixture screws, that problem goes away.
Proper synchronization is necessary to insure that one carburetor isn't "leading" the others.
Exacting bench sync isn't always correct. Must be done on THAT running motor, not someone else's. Valve sealing condition, overlap, any minute vacuum leak, etc. will alter sync.

Where did you get the right drill bit? Or do you just replace them?

A #79 drill bit equates to .38mm. I buy them from McMaster-Carr in extended reach.

See here: https://www.mcmaster.com/3096A197/

Or, buy new jets.

Jets MUST be extracted for drilling so the tiny particles don't get caught in the passages.
Machine them in a miniature jeweler's lathe or a hand "pin vise".

CBX-tras wrote: ↑

Thu Oct 01, 2020 9:01 am

A #79 drill bit equates to .38mm. I buy them from McMaster-Carr in extended reach.

See here: https://www.mcmaster.com/3096A197/

Or, buy new jets.

Jets MUST be extracted for drilling so the tiny particles don't get caught in the passages.
Machine them in a miniature jeweler's lathe or a hand "pin vise".

Thanks for that JR...