vacuum barb flew out of manifold

[mph]

have a 1981 XS650. I went to start it today and something flew out from the carb and hit me in the right leg. I picked it up and it appears to be a vacuum barb / nipple thingy. The carb manifold for the head on the left side has a vacuum hose that runs from the manifold to the petcock. But the right one just has the barb/nipple with a hose end/cap clamped on it. Well the little nipple flew right out of the hole on the manifold and I am able to just slide it back in easily but it doesn't stay. It is not threaded so I am unsure what held it in the first place. Not sure how to get it to stay in there or if I have a bigger problem..

In this photo you can see the open hole on the manifold and I rested the nipple below on the case.

Would appreciate any help.

 

[weekendrider]

JB weld. I suggest leaving a shoulder on the inside and adding à ring of JB around it. These don't happen to be MikesXS manifolds do they?

 

[mph]

Stock I believe. They need to be welded? How did they stay in the first place?

 

[xjwmx]

You could cut an X into the end and flare it a little with something to keep it from coming out. Include some kind of sealer from Autozone like Motoseal 1 so it wouldn't leak air.

P.S. what happen to you your pilot screw "tower"? Looks drilled in the side.

 

[grizld1]

Note to OP: No, the barbs don't need to be welded, you'd destroy the rubber if you tried that, right? JB Weld is a tough 2-part epoxy. I can tell you from experience that it will work fine. Use the original formula JB, not the quick cure type. Clean barb and mount with a bit of rubbing alcohol. Fill the hole in the mount with JB Weld, push the barb into the hole, and build up a small bead of BJ Weld around the barb. Push a drill bit through barb and hole to clear them and wipe away excess inside the mount with a rag and alcohol.

 

[mph]

Note to OP: No, the barbs don't need to be welded, you'd destroy the rubber if you tried that, right? JB Weld is a tough 2-part epoxy. I can tell you from experience that it will work fine. Use the original formula JB, not the quick cure type. Clean barb and mount with a bit of rubbing alcohol. Fill the hole in the mount with JB Weld, push the barb into the hole, and build up a small bead of BJ Weld around the barb. Push a drill bit through barb and hole to clear them and wipe away excess inside the mount with a rag and alcohol.

OK. Didn't know about "JB Weld". I'll have to try. You said, wipe away "inside the mount". Can I leave the carb on the bike when I apply it or do I need to remove it?

 

[mph]

You could cut an X into the end and flare it a little with something to keep it from coming out. Include some kind of sealer from Autozone like Motoseal 1 so it wouldn't leak air.

P.S. what happen to you your pilot screw "tower"? Looks drilled in the side.

I don't know what happened there. One appears chipped.

 

[grizld1]

Already told you what I'd do. By all means do whatever you want to do, it's your bike and your job.

 

[mph]

OK. Thanks.

 

[weekendrider]

mph, sorry I just took it for granted you knew what JB weld was. I would remove the carbs and the manifold.

 

[xjwmx]

JB is two-part epoxy with some heat resistance. If regular epoxy sees much heat it turns to jelly. What they're describing is easiest and apparently it's been done before... If nothing works for you, a new carb boot on ebay isn't much money, relatively speaking. Always keep your old broken parts in a box even if it seems to make no sense at the time.

 

[mph]

Revisiting this old thread now for a [great/stupid] question:

What was the purpose of the right hand side vacuum barb in the first place? The left side had a vacuum hose attached and apparently only one was needed. Would there be a reason to add an additional hose? If not, why wouldn't this hole have simply been sealed up permanently instead of having a rubber cap and clamp (which seems like it would be left that way in case of future use)?

 

[grizld1]

There are no manometer ports on your BS34s. Manometer hoses are attached to the barbs in the carb boots when throttle synchronization is set.

 

[mph]

I see. So I probably should have synced them with one of these:

https://www.mikesxs.net/yamaha-xs650-carb-sync-gauge-set.html

 

[grizld1]

Or with Motion Pro carb sticks, or with a home made yardstick manometer. Just a little bit of effort on your part will turn up lots of options. Good luck and goodbye.