The International CBX Owners Association

The site is a bit overwhelming with the knowledge and trying to find my issue.
Don't want to duplicate an existing thread but...........can't find out why the small tube coming off the vacuum breaker on the top of the carbs has a small gas drip coming out.
Is that tube to be connected somewhere and I have it open to the atmosphere? Or Is there something goofy with the vacuum breaker itself?

I hope it is called the vacuum breaker.

The vacuum valve is damaged and leaking fuel into that chamber.
Frankly, I don't trust them and replace the eliminate the entire mess.
The only downside is that you need to get into the habit of turning the petcock to "OFF" whenever the bike isn't running.
It's a perfect place to install a Tee and an inline filter that is easily serviceable.

Thanks for all of that. Of course I must ask, where do you get the "T"? Never mind......I will find it.

I will take off the breaker but that hose coming off of the breaker terminates in the back of the carbs. What to do with those? Thanks again
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Just put a vacuum cap on it.

NobleHops wrote: Sat Apr 26, 2025 4:25 pm Just put a vacuum cap on it.

Like the other 5 are capped.

Vacuum cap for the next time you sync the carbs.

Thanks for all of that. My carbs have screws blocking the vacuum ports. Is it suggested to have brass extensions put in the place of the screws and put caps on those? Thanks

I've installed small m5 adapters with a cap on them?, but you can extend with vacuum hoses and have a bracket made to have a bank of 6 connections in line for easy balancing going forward?

Many of the sync tools you find include a set of what you describe - short brass tubes, threaded at M5 x .8 with stop nuts and orings, and a slot cut at the end to fit a flat screwdriver for installation. When we are shaking down a bike, we will often leave those installed, just for ease of rechecking carburetor sync. I can’t see the harm in doing as you say and just fitting a set permanently, including good-fitting vacuum caps, if you are really ambitious enough to be syncing them that frequently.

OK, thanks for all of the great advice. Wish I could return the favor........just imagine my face filled with excitement knowing the steel horse I ride is working partly because of those like you all who are not arrogant or snobby enough to share what you know.
Bud in Goodyear.

Just get another aluminum port screw - don't worry about a washer, most are missing anyway. If the carbs are right and you get a good gauge sync done once, you'll likely never touch them again anyway.


Dave

budanddar wrote: Mon Apr 28, 2025 4:47 am OK, thanks for all of the great advice. Wish I could return the favor........just imagine my face filled with excitement knowing the steel horse I ride is working partly because of those like you all who are not arrogant or snobby enough to share what you know.
Bud in Goodyear.

Really, it's a pleasure to help you and others. We all get a lot of joy in seeing someone succeed at putting one back on the road. Don't ever be shy about asking your questions, or if you are seeking a source for a part.

N.

Thanks you guys (I guess you are all guys) for the help. Hooked the carbs to the overhead mounted gas tank and some leaks that lasted 2 minutes. #6 took a little bit longer to stop.
CBX-tras.....replaced the vacuum breaker with parts from Ace Hardware. It was about $31 for the small parts.
The rest....thanks to Nils, bobcat, Dave's 79x, and banjobill08.
Will be putting the carbs on today and cross my fingers there are no more issues. What a dream, right?

Filter?