Header pipes have holes!

[xsleo]

Good point. I don't really like chrome, so that wouldn't bother me.

[tonyc2me]

I tried Pete's idea and also welded it. Eventually I am adding Cherry Bomb mufflers and all will be ceramic coated. Tony C.

[dillrepair]

the muffler shops i went to didn't have anything that small to expand pipe sizes.... if you find anyone that does or know a tool the right size let us know. I ended up trying a fiberglass exhaust patch kit to patch the holes at the head before wrapping my headers with insulating tape.... it didn't last long. i bought the right adapters and even after the filing they were still too far off when measured with the calipers... i noticed there was a lot of variation in the way these adapters looked at the store (the same part # i mean) they are roughly manufactured so that probly has something to do with it.

... maybe sometime when i have to take them off again i'll try welding or inserting a slice of pipe the right size to block the gap between the inner and outer pipe... i don't have a welder though so...

[awrallybike]

Hello,
So I wanted to clarify something. I also looked at the exhaust after feeling exhaust blowing out the exhaust port. When i took of the headers you can see the two separate pipes. For some reason there are two offset holes one drilled into the inner pipe and second offset barely overlapping the outer edge of the circle. This is the part that is blowing my mind! Not sure if this is the whole you are referring to above. Since the adapter would prevent leakes of a outer hole not both inner and outer. The hole starts right after the manifold bracket and can be visible just past the manifold finned flange. But seriously. how is doing anything to the coupler going to prevent the blow-by at the top of the header. Second why on earth would any exhaust system have this? Is this even normal? Finally i do recall stumbling upon some exhaust manifold inserts that seat inside the exhaust manifold and exhaust ports on the block. These parts were noted as performance for modified exhaust on mikesXS, and i may have seen some somewhere that were sleeves to replace stock gasket ring. Not sure who else is familiar with this sleeved insert, if it would fix the problem, or if this is a normal exhaust issue with the holes. How can i tell there are holes on inside and out, 1 in can see light on inside of inner hole from light passing through, second, there is a F#$%&!@ hole "on the inner wall". K, just wanted to clarify the issue. Ill take some pics possibly tomorrow.
Thanks,

Anthony

[xsleo]

On the three sets of stock exhaust I have. A 75 An 81 and 82. The headpipes are a two pipe sewtup. An inner and an outer. This is done to prevent discoloring of the chrome on the outer pipe. At the head end of the pipie the out is welded to the inner just behind where the finned clamp pushes the ring into the head.
About 1/2 inch behind the weld are two holes. Down by where the mufflers hook on are more holes. These holes allow air to pass between the pipes and keeps the outer pipe cool enough so it won't discolor. On the 81 and 82 the stock mufflers are welded to the headpipes. The inner headpipe is welded to the inner baffle of the muffler. The outer headpipe is welded to the inner baffle and the outer case of the muffler.
On the 75 exhaust the head pipe is very much like the 81 and 82 headpipe. Where the mufflers hook on are not welded on, they slipon with a gasket and a nut to prevent leaks. Where the mufflers hook on the headpipes inner and outer are welded together. This is so when the mufflers are clamp to the outside of the headpipe, exhaust won't leak back up between the pipes. On the 81 and 82 pipes to replace the mufflers you need to cut the mufflers off the headpipes. Then you need some kind of adapter to prevent leaks.
On the 75 you just pull the mufflers off and slip on the new. No adapters needed.
Unless you need them to go from 1 3/4" pipe to 1 1/2 " pipe. They usually come with the mufflers. Thst why I suggested welding the two pipe together at the end. The mufflers will cover the weld. Unless you need a short pipe to extand the headpipe so the mufflers fit back farther.
With my 75 headpipes I need about 7 inch extension to get the Harley mufflers back so they will mount to the stock muffler brackets off the foot pegs. I have had them mounted and didn't like the look or sound. I doubt I'll use them.

[pamcopete]

Here is a procedure to install 1 1/2" mufflers to the inner pipe of the stock double wall headers.

Here are the materials you will need. All together cost about $10.



That object on the left is a brass, chrome plated, 1 1/2" sink drain pipe. I have already cut a section out of it and split it to be used to cover one of the adapters.

Here is a picture of the adapters connected:



Here is what they will look like with the piece of chrome drain pipe:



Here are the adapters and the chrome cover installed in the muffler:



And here is the finished installation. Notice how the chrome drain pipe cover hides the adapter:



Start by fitting the first adapter onto the inner pipe of the header. You will have to file the inside of the small end of the adapter and, as much as possible, the outside of the inner pipe.

I did this procedure to install Mikes #07-0065 "Commando" mufflers on my '81/H to work with Mikes 32mm Keihin Flatslide PWK Carb Set . This is a great combination, along with the "Ultimate" PAMCO ignition.....awesome power!!