Missing cap or hose on carb

[gkeithly]

Hey y’all,
was riding my ‘81 xs650 to work I was fighting a high idle issue. I found this barb uncapped/no hose on the carbs on both sides. Is this just supposed to be capped off or am i missing a line? If so, where does it go? Both ends feel suction when I cover them and cause engine to rev when starter fluid is sprayed. Barb is next to finger in photo

 

[Jim]

Yes, those are vacuum sources. Normally the left one has a hose to the vacuum petcock and the right one's capped. If you're not using the vacuum petcock, just cap both of 'em.

 

[gkeithly]

Great, I’m glad it turned out to be an easy fix. Honestly have no clue if I’m using the vacuum petcock, I’ll look into it and fix it accordingly.

Edit: after looking up what one is I definitely don’t have one haha. Will cap
Thanks

 

[gggGary]

Vacuum ports one on each side. The left side originally fed the vacuum petcock the right is capped.
These dorman vacuum caps work great most auto stores have an assortment on a card.

https://www.dormanproducts.com/p-6911-47397.aspx
Always use a clamp on these, no matter how tight it seems a light backfire will send them sailing never to be seen again.

 

[gkeithly]

Vacuum ports one on each side. The left side originally fed the vacuum petcock the right is capped.
These dorman vacuum caps work great most auto stores have an assortment on a card.
View attachment 240356

https://www.dormanproducts.com/p-6911-47397.aspx
Always use a clamp on these, no matter how tight it seems a light backfire will send them sailing never to be seen again.

Yeah I plan on it. I’ve already replaced all the springs type hose clamps with worm drive as after 42 years the spring ones do not hold any force…

 

[gggGary]

Vacuum petcock are OEM on all special gas tanks, the handle will be marked on res pri. for; on reserve and prime.
The vacuum line connects on the back side.

 

[gggGary]

Yeah I plan on it. I’ve already replaced all the springs type hose clamps with worm drive as after 42 years the spring ones do not hold any force…

Careful with worm drive clamps at these small sizes, they often distort and you end up over tightening them to stop leaks. The fuel line eventually cracks and leaks at the clamp. new spring clamps are the normal replacment, band type or double wire spring clamps hold well.

 

[nj1639]

I link those two barbs together with a length of vacuum line, about a foot long. I like to imagine it helps balance the pressure between the inlets......yeah, that's it. Bike doesn't mind.

 

[5twins]

After trying cheaper automotive rubber caps, I found they didn't last very long, so I've gone back to using the still available original rubber caps and clamps. Expensive yes, but they work and last .....

https://www.partzilla.com/product/y...?ref=8b425f3ca82e2d7b1a9774da19a9fa73be6e4324

https://www.partzilla.com/product/yamaha/90467-10039-00?ref=8b425f3ca82e2d7b1a9774da19a9fa73be6e4324

 

[Vincenthdfan]

After trying cheaper automotive rubber caps, I found they didn't last very long, so I've gone back to using the still available original rubber caps and clamps. Expensive yes, but they work and last .....

https://www.partzilla.com/product/y...?ref=8b425f3ca82e2d7b1a9774da19a9fa73be6e4324

https://www.partzilla.com/product/yamaha/90467-10039-00?ref=8b425f3ca82e2d7b1a9774da19a9fa73be6e4324

^^^This!^^^

I put fresh Dorman rubber caps on the unused vacuum ports of my Wife's Ranger pick up when I swapped the motor and transmission out.

Imagine my surprise when, a couple months later while changing the oil out, I found all the caps already had weather checking/cracks in them! More Chinese crap...I get so tired of fighting their substandard junk that they push on the rest of the world these days. Then we, the consumers, have no choice but to deal with it because its just about the only thing vendors sell anymore.

 

[gggGary]

Yeah auto rubber vacuum caps suck but those colored vinyl ones hold up excellent.
PS some of the other sizes make great bolt caps when a "too long" bolt thread is exposed. I've been using them on my clamp on handlebar mirrors.

 

[jetmechmarty]

After trying cheaper automotive rubber caps, I found they didn't last very long, so I've gone back to using the still available original rubber caps and clamps. Expensive yes, but they work and last .....

https://www.partzilla.com/product/y...?ref=8b425f3ca82e2d7b1a9774da19a9fa73be6e4324

https://www.partzilla.com/product/yamaha/90467-10039-00?ref=8b425f3ca82e2d7b1a9774da19a9fa73be6e4324

I am in this camp as well. Even the OE caps don’t last forever.

 

[5twins]

Yes, but the automotive ones I was using would split within a month or two. The originals will last for years, and I've laid in a supply of extras, lol.