Well let me start off by saying it worked, and I am very happy!
Here is what I started with. Piggies cut off flush and previous owner said two baffles drilled. I'll have to take his word for that unless there is a way to check?? (pic is from a previous project)
Discovered that a 1/2" pipe tap fits nice in the holes that are left.
Not enough room under there for a T handle with the bag rails so just use a crescent wrench. Have to be careful to get it started straight.
I think you see where this is going. I picked up 6 copper fittings. 1/2" pipe to 3/4" copper. The only down side I see is the ID of the threaded end of the fittings is a little restrictive. I ended up buying them at a local "old school" plumping supply place. Lowes wanted over $5 each. I paid $2.39. They only had 6 and they are from two different suppliers or decades. They have two different ID's. I plan on drilling them all out to 5/8" over the winter.
I had some 3/4 copper laying around. The longest I could fit in there with the curved pipes was 10"(plus the fitting). Actually two 10" and one 9" on the far inside. Still gets the exhaust to the end of the pipes which is what gets rid of the drone. It would be even better with straight pipes.
They are not in there final positions in that pic. Just a test run.
If you used soft copper you could probably even shape them to fit stock tips. The stuff I had on hand was the harder type.
While I was using the shop vac to get the shavings out of the pipes this piece of metal came back to the hole but wouldn't come out. I got a hold on it with some needle nose vise grips and had to cut it to get it out.
Looks like a plug left over from manufacturing process. Must have been a slow day at the Honda factory. I could always hear a rattle it that pipe at idle. I always thought it was debris in there from the original owner drilling the baffles.
Anyway, I would have to say it was a success. Went for a 80 mile test ride. Sounds like a jet powered Porsche at hard throttle above 4 grand(man o man what a machine) and just a slightly irritated hornets nest cruising at 3 with very little drone. I can actually listen to my tunes in the helmet now. I'm sure you could tune it to whatever you wanted with different lengths of pipe and tips.
