Vacuum Barbs

[rossness]

Hey guys,

Where the heck do I find the barbs for the '76 carbs? My carbs are close to sync and I'd like to buy a manometer to actually get them perfect. I have '76 carbs with the small screw plugging the vacuum port, but I can't find the dang thing anywhere on the internet. Help?

 

[toomuchstuff]

Hey guys,

Where the heck do I find the barbs for the '76 carbs? My carbs are close to sync and I'd like to buy a manometer to actually get them perfect. I have '76 carbs with the small screw plugging the vacuum port, but I can't find the dang thing anywhere on the internet. Help?

Try searching for Motion Pro carb adapters. I think the BS38s use 6mm adapters but confirm before ordering. Just pull the bolt where you will install the adapter and see if it is 5mm or 6mm. They can usually be found in 5mm or 6mm sizing.

 

[YamadudeXS650C]

I bought the EMGO gauge synchronizer, which works well.
It comes with adaptors that fit the '76 carbs.

https://www.ebay.com/itm/MOTORCYCLE...379?_trksid=p2349526.m4383.l4275.c10#viTabs_0

...and the nice looking gal comes along to help set it up.

Correction:
Oops ! I had to buy the Motion Pro 6mm adaptors. Item #150442

 

[DogBunny]

Unless you have a two-into-one exhaust, you really don't need a manometer to sync carbs. Just put your bare hand a few inches behind the pipes while at idle, and adjust the sync screw until the pressure feels equal from both pipes. This may seem imprecise, but it is perfectly adequate on these bikes. The sync is sort of a "floating point" anyway. f you adjust with a manometer, and then change the idle speed the slightest amount up or down, you will instantly loose your perfect sync according to the manometer.
Adjust sync by feel, and do a test ride. If you experience popping on decel, or other inconsistencies, a slight turn in or out with the sync screw will fix it, assuming all else is good with your carbs and engine.
In case you think I'm full of it, this technique is posted on Michael Mercury Morse's 650central.com site, under resources: Farrell's Shade Tree Corner:
https://www.650central.com/fcarb_balance_technique.htm
I've used this method ever since I read about it years ago, and if it's good enough for MMM, it's good enough for me.