Anyone got the best method for soldering that tube closed. I tried a plumbing torch and could not get it to take. How did you do it?

i needed the nipple gone so i cut it off drilled the hole and tapped it. i put gasket maker on the threads and bolted it down.

I ran a good hose off it and plugged it remotely by the rear cylinder so I can still use the vacuum reference value for tuning and troubleshooting, but I'm in the minority on this. I see plugging that thing up as throwing away a tool in the toolbox just because it crowds the drawer a little. I imagine you'll have to clean the living crap out of that nipple and lay the flux to it to get a good stick on it.

I just dipped it in flux and soldered it shut with a propane torch. No problem. Just don't get it to hot and it will take.

If you think it needs to be cleaned better shove the bristles on a wire brush into it and clean it.

I agree with JD. A good piece of plugged vacuum hose won't deteriorate like those caps. And you might want to use it later.

I did mine with just a bit of paste flux and a regular soldering iron. Worked fine. A torch seems like overkill to me.

I'm interested in what kind of tuning or troubleshooting you'd do with the vacuum.

Use Acid Flux Not electric Rosin flux, and plumbing solder instead of electrical solder with Rosin core. There is a big difference between the two. Electrical solder is weaker as far as strength goes. The Acid flux cleans the metal up and helps the solder flow/bond better on the tube. Just make sure to remove the excess flux when your done or it will corrode the metal.

Woody

My old manifold was cracking so bad that pieces of rubber were falling off of it. I simply cleaned the nipple on the replacement with a wire brush, dribbled some MEK thru it, and fingered some JB Weld into the hole from the top. Capped it, and can easily drill it open is needed.

Vacuum readings...
http://www.international-auto.com/fiat-lancia-tips-on-reading-gauges/tips-on-reading-gauges-vacuum-gauges.cfm

That's a good tip sheet. Standard vacuum value at idle for a 1600 is 15.4 inches Hg. For a 1700, 12.8 inches Hg. Mine runs slightly higher vacuum at 16.2 Inches Hg, but the air cleaner area and more free flow of the K&N vs the stock filter and box (where the "standard" comes from) accounts for a nice bump. If you establish a baseline for your engine, you can use it to diagnose anomalies as they appear. To use a vacuum gauge with our bikes, it's best to "buffer" the line, or you'll never read anything but a windshield wiper. Since we have no manifold volume, like a car engine, the surges of the cylinders easily feed back into the intake. This can be seen as the "breathing" effect that Curt talks about. I use my old #35 pilot inline in the hose as a buffer. With this buffer in place, you will get a nice steady value. You will drop tenths very quick with leakage in the intake, and may even see oscillation in the needle on the gauge re-appear. It's an old school tool, but a valuable one. You could diagnose SVS with one as well, but you need your baseline setup to have anything of value to go by.