Vacuum Lines

[TheRev]

Hello All

I have a couple questions. I have a 79 xs1100 standard without the fuel octypus. I know the vacuum advance goes to the port on the number 2 carb body. My question is what do I do to the vacuum ports on the carb boots? My hunch is that I just cap them off but I'm not quite sure. I believe I will need them open to do the carb sync. Also, where might I find the caps? One last question, I don't have my digital dash hooked up yet, nor do I have a working OEM dash. However, I want to start the bike for the first time since I began the rebuild two years ago. My question is, without a oil light to warn me how can i make sure the oil is pumping up to the top end?

[natemoen]

The standards do not have the octy, they have vacuum operated petcocks. There needs to be a vacuum line run from the forward facing nipple on the petcock to one of the nipples on the carb boot (usually left petcock to #2 boot and right petcock to #3 boot). You can cap the other 2 boots off.

Those boot nipples are where you hook up your sync tool. Those caps can be found at any auto parts store. They are just vacuum port caps.

[BA80]

You can use a test light as a makeshift oil light. Clip the test light lead to the connector on the oil sending unit and the other end to power. The light will be lit. If it goes out once the engine starts you have oil pressure.

[BA80]

The standards do not have the octy, they have vacuum operated petcocks. There needs to be a vacuum line run from the forward facing nipple on the petcock to one of the nipples on the carb boot (usually left petcock to #2 boot and right petcock to #3 boot). You can cap the other 2 boots off.

Those boot nipples are where you hook up your sync tool. Those caps can be found at any auto parts store. They are just vacuum port caps.

Correct, I forgot about that question.

You can get caps that will work at any auto parts store. The yammi dealer has the good heavy ones though.

[MPittma100]

Vacuum Lines

If you want the original type vacuum caps:

http://www.mikesxs.net/product/48-1447.html

[BA80]

$2 each

[natemoen]

If you want the original type vacuum caps:

http://www.mikesxs.net/product/48-1447.html

I dont think there are any good rubber products on that site. certainly not "original".

[motoman]

$2 each

More than that OEM..........and put them back in their packaging as they slipped off easily when hot. Went back to the heavy duty ones from NAPA....go figure.

[TheRev]

Awesome. Thank you all for the suggestions. I will try to figure out a test light. Thanks

[BA80]

More than that OEM..........and put them back in their packaging as they slipped off easily when hot. Went back to the heavy duty ones from NAPA....go figure.

The OEM ones had spring clamps holding them on.

[motoman]

The OEM ones had spring clamps holding them on.

Yup.......and still did with the new OEM caps......no joy. I would imagine the 32yr.old spring steel has lost some of its return tension. Already having several of the other new vacuum caps, that was the quicker option at the time and just left it that way.

[TheRev]

So I bought a test light today. So tomorrow I will hook it up. I just want to make sure I get this correct. I hook the test light clip onto the positive side of the battery and touch the oil sensor unit with the tip of the test light? Is that correct. The guy at the auto shop told me that the test light clip goes on ground not on power, so I am just a little confused. Thanks

[TopCatGr58]

Hey Rev,

The oil pressure switch is just to complete the circuit to ground. With the engine off...the spring inside the switch keeps the switch CLOSED so continuity, and you will see LIGHT on your test light when you contact the Negative Probe to the SCREW terminal of the pressure light switch. When the engine is running, oil pressure pushes the switch OPEN, no continuity, and therefore no path to ground thru that screw terminal, so NO LIGHT should be seen with your test light. Yes, the Positive end of the test light is to be connected to 12+V battery source. And just test the light by touching it to GROUND first to make sure it does light, then to the switch terminal screw/nut, it should still light with the engine off. You should NOT see a light with the engine running PROVIDED YOU HAVE OIL PRESSURE, and your pressure switch is working correctly!

T.C.

[TheRev]

So when I do my carb sync with a temporary gas tank that is non vacuum do I cap all the carb boots?

[natemoen]

So when I do my carb sync with a temporary gas tank that is non vacuum do I cap all the carb boots?

No, you need to have those uncapped so that you can hook your sync tool up to those.