1977 Vacuum Intake

[Diff3RentBreed]

I have been trying to find this for days. I dont know if im just searching wrong or what. Im looking to sync my carbs and I dont know where the vacuum is. If someone could point it out with a picture, that would be wonderful.

Thank you.

 

[fredintoon]

Hi Diff,
go here:-
http://www.xs650direct.com/products-40.html
Scroll down to #48-7479
Those little brass tubes sticking out are the vacuum connectors.

 

[Diff3RentBreed]

So I would have to purchase those in order to sync the carbs?

 

[fredintoon]

Only if the carb manifolds on your bike don't already have them.
I'm not sure if the '77 models came with vacuum barbs on their manifolds or not.
I've gotten away with static-synching my carbs by setting both butterflies to have an equal grip on thin wire.

 

[gggGary]

77 BS38s have vacuum ports on the outsides of the carbs with caps screwed in them. They're a bit hard to get at. I ended up making a special barb set to fit in there and clear (the enricher body).

You can just get some straight metric zerk fittings, drill out the ball and spring and "there you go" your manometer tubes will push right over the ball ends.

 

[gggGary]

OK I went and looked, they aren't hard to get at but it's easy to interfere with the throttle linkage.





There is a second capped port on the INSIDE of the LH carb. (Usually?)

 

[Grinder]

Ditto on the zerk fittings, used them on my 77.

 

[fredintoon]

Ditto on the zerk fittings, used them on my 77.

Hi Grinder,
well, you learn a new thing every day if you ain't careful.
No wonder Diff couldn't find those vacuum ports, effin' brilliant way to hide the bastards, eh?
If ever I'm faced with having to dynamic-balance '77 carbs do I leave the drilled-out Zerks in place with caps on or do I remove the Zerks and put the masking screws back in?

 

[gggGary]

well the left one kinda interferes with the throttle linkage.

 

[XStretchified650]

I have 77. I used the 6mm Motion Pro barbed inserts. Clearance to the throttle linkage is miniscule but the barbs don't touch the linkage even with the MP provided rubber barb caps in place.

The barbs came with funky washers so I used the washers off of the screw plugs.

I trimmed the barb caps because they stuck out way too far, (far enough to be snagged and lost by a pant leg). The barb caps fit snug and I don't expect that they'll leak.

Yeah,...... I inventoried the screw plugs in case the caps do leak but for now I'm leaving the barbs in the carbs.

XStretchified

 

[Diff3RentBreed]

Boy have I been a busy guy these past few days. Thank you so much for the images. I didn't know what you were talking about until I saw those. I thought they were the ports above those bigger ones because they looked more capped off on mine. So thank you again!