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Here are some pictures of my balance tube.

The main tube is made from Schedule 40 1.5" PVC.

Bent the tube to match the proper angle (approx 60 degrees) so the 1/2 rubber hose's would fit the existing 3/8" fittings in the intake manifold.

Then I found two 1.25 x 3/4 schedule 20 inserts. Turns out the 3/4 threaded fitting fits the 1/2" fuel tube I used.

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Next, I turned the inserts down to fit inside the Schedule 40 pipe. I couldn't find Sch 40 fittings at my local store so had to use the Sch 20 size and make it fit.

The main pipe is 11" long - then took the pipe and fittings and hose out to the airplane for a final fitting before gluing it all up. Used regular PVC cement for the inserts and screwed the hose into the fittings with clear GE Silicone seal to secure the hose to the inserts.

I think that this could all be built out of Schedule 20 material and instead of bending it, there are 60 degree elbows available. So, maybe two short pieces of 1.5 OR even 1.25 inch PVC with a 60 degree coupling and two inserts with a threaded 3/4" female threads might work. Haven't built one, so am being a little conservative here.

After a 1 hour flight yesterday, I landed, took off the cowling and I could hold the balance tube with my hand. That tells me it isn't getting too hot.

So far, I'm really pleased with the setup. If anyone sees a serious problem, please let me know. I don't know the long term affects of heat on the plastic, but I know it took about 300 degrees of heat to bend the main tube, and it's not getting anywhere near that hot under the cowling. I didn't have to modify the manifolds, just used the existing ports.

I did go back this afternoon and used Kitfox 2009's procedure for balancing the carbs. I hooked a 1/2" fuel tube from one carb to the other, and using the idle adjustment on one carb, got the engine as smooth as I could. Then hooked up the carbmate and balanced at 3500 rpm.

I have about a six hour flight tomorrow, so will report back on how things went. Also, and I haven't really figured this out yet, I can now use my Hacman system to lean the engine. Before the balance tube mod, running anywhere from 5300 to 5600 rpm, as soon as I cracked open the leaning knob, the engine got rough. Could not get any temp rise in the EGT's or decrease fuel flow. A quarter turn was too much. Then, on my first flight after installing the balance tube, I can now lean the engine. I've been trying to get my EGT's up in the 1400 degree range to seat some new oil rings, and I can finally do that.

So far, this has been a really good improvement to the way my engine operates. Nice slow idle (1400 rpm) and I can lean the engine at cruise

Rodney