So I picked up a 72' about a month ago and have been tinkering with it. It was leaking exhaust up at the heads mostly in the rear but on both cylinders. It looked like the bike may have fallen over on a trailer or something because the pipes were cockeyed. Any how I took it apart to find that the front exhaust bolt had been re tapped to 3/8 and the rear was 5/16. I don't know if the threads were already kind of jacked up but am guessing they were and I managed to strip about half of the 3/8 threads out. I'm gonna get another bolt tomorrow and cut it down to where it just a little shorter than the hole. Also can a man double stack the exhaust gaskets or anything like that ? The reason I ask is the flange on the pipes doesn't fit the same all the way around. I tried tweaking on the lower bracket but after the bolt ordeal basically had to walk away for the night.

 

If there is enough meat in the 3/8 hole you might be able to helicoil it back to 5/16 x 18. One trick to sealing the exhaust is using one of the woven steel evo gaskets. The bolts were never meant to support the weight of exhaust. Make sure you adjust the brackets to hold the pipes in the correct position then tighten the bolt.

 

Look for these online or at a local old time auto parts supply house or speed shop they are called step studs , they come on a few size's and thread combo's .These and the green loctite I've repaired many a fubar shovel exhaust port in the bike. Oh another tip grab a tube of Permatex Ultra Gray and use a healthy smear around the inside of the port and on both sides of the gasket before you put it all back together making sure the rear pipe mount is straight and solid, clean off any excess, let her sit overnight and pipe should stay put. Yet to have one come back doing this.

 

If you use a 10mm x 8mm step stud it may help...10mm is slightly larger than 3/8...and 8mm is almost the same size as 5/16 so it will fit the exhaust hole...you will have to use 8mm nuts.


https://store.034motorsport.com/step...mm-to-8mm.html

 

I get them in 3/8-16 as that's what most are tapped out to and the smaller end with 5/16-24 so I can use 3/8" 6 or 12 point head aircraft locking flange nuts on them . Allows you get the box end of the wrench on the nut not just the flats. Ebay surplus sites have been my source on those. The studs check Jegs online, napa auto or auto & boat speed shops the older the place the better.

 

Old Shovelhead rider trick is to use the Evo crush gaskets under the shovel gaskets to take up the gap. Use the good thick shovel gaskets that have a bolt hole in them on top and the Evo mesh gasket underneath. Line everything up and make sure you secure the pipes/mufflers to the frame as well.

 

Thanks for the replies guys. TwiZted I have been looking for those step bolts without much luck on just buying a single or two .I have tried searching using different key words and what not. I remembered you posting about them before in another thread. If your interested in selling me one or two PM me please. I think I am also gonna look around for a new mount bracket.

 

Let me check the stash and see what I have left, been a while since I've used any. If I have a few extras I'll PM you for an addy and just drop it in the mail & call it an early christmas. No promises

 

Might check your local Ace hardware store also seems I remember running across some in one locally.

 

That works for me. I'll check with the local stores also.