marshall13 wrote on 05/20/09 at 17:13:47:ok, od is 1 5/8... thats the rough id of 1 3/4 od exhaust tubing... so, hit your local purveyor of auto part, and get as short a length of 1 3/4 as they sell... you only need a few inches... use 2 clamps(1 for each joint, headpipe to your new piece, new piece to muff) make it long enough you can get both on and sealed (dont crowd the clamps)... use the factory end on the headpipe, and if your cut is a little offsquare on the other end, its hidden inside the muff inlet... after you get it all lined up and together loose, loosen up the headpipe retaining bolts at the head, and then tighten everything in sequence, starting at the head, and ending at the muff support.... if you're gonna do the 7 degree bend, then just get the whole shebang at a muffler shop...
edit... i just looked at your new pic, and re=read your dimensions... the 7/16 long section of 1 5/8(the smallest diameter piece of pipe, left in pic) is the headpipe.... you then have a cylindrical sleeve(a couple inches long, heading right in the pic), that ends in a shoulder, then the curve of the outer pipe of the header... the id of the adaptor piece you are fabbing has to fit the od of that larger section behind the 7/16 long stub.... it has to butt against the shoulder at the right end of it in the pic.... the 7/16 long stub isnt long enough to clamp to, it will always leak if you clamp there... so, pull out your calipers again, and measure that cylindrical section just to the right of the stub in the pic.. that will be the id of the front of your adaptor... the other end of your adaptor will be 1 3/4 od... now for the explanation of the solution and problem... the muff mount bracket, and the rail for the bolt on the muff kept the muffler from actually sealing on that cylindrical section, as the mount kept the muff too far to the rear...the muff inlet should have butted against that shoulder, it didnt in your pics....the short sleeve you are fabbing fits over the full length of the headpipe, from that shoulder to the tip, plus a couple inches to go in the muff inlet... that allows the adaptor you fabbed to seal on the headpipe, then the muff to seal onto the adaptor, and the rail slot to align with the mount for the muff... your finished piece should be somewhere around 5-7 inches long(length of headpipe tip to shoulder, plus depth of inlet nipple in muff, subtract a half inch for fitting, equals the length of your adaptor piece...) im hoping this verbose explanation clarifies what im talking about, as opposed to just further confusion....lol
The OD of the sleeve is 1 5/8. I assumed that was part of the header.
The Harley muffler won't butt up against the shoulder. The shoulder is roughly 2 1/2" from the end. About 2" into the muffler, it narrows. I'm not sure how much. Which is why in the pictures there's roughly 1/2" between the muffler inlet and the sleeve shoulder. I could try to force it on, but the way it lines up it would be against the rear brake cable. I assume that would be bad.
The mounting rail on the muffler is a long slot, so I can adjust it. The bolt that used to be in there was jammed. I messed it up pretty bad getting it out. Time to buy a new bolt! The point being that the mounting didn't affect how far it fit over the header. Just the angle.
I think it works out to 2 issues. First, the 7 degree angle between the muffler and the header. Second, the ID/OD difference.
marshall13 - I appreciate you taking the time to work through this with me. I'm not intentionally being slow, I'm just new to this.
Does anyone know where the 7 degrees came from? I assume someone measured the stock muffler.
-D. Dwarf