Topic: Installing Mac exhaust

[70CB750]

I have new old mac 4 to 1 exhaust. Comparing original spigots to this exhaust the distance from the flange to the sealing end the mac is inch longer - too long for the head actually.
I am thinking about cutting that end shorter to get the flange - after crushing the copper washer - to sit directly on the head.

Is there a trick to mac exhausts or anybody has experience with it?

Thanks!

[dhall57]

This is the Mac 4 to 1 system that the PO had put on my K6. Maybe this pic will help 70CB.

[70CB750]

Thank you, is there space between the flange and the head?

[Steve_K]

I have a similar exhaust and it used the allen head cap screws to hold it to the head.  Mine is hanging on the shop wall and I want to use studs to hold it on.   Anyone know how long they should be using washers, lock washer and the nut? 
Steve

[dhall57]

Thank you, is there space between the flange and the head?

I've had the pipes off several times for painting, etc. and mine have no spacers, just the mounting plates that are part of the pipe assembly.  The pipes just bolt down to the exhaust head studs.

[seanbarney41]

I have new old mac 4 to 1 exhaust. Comparing original spigots to this exhaust the distance from the flange to the sealing end the mac is inch longer - too long for the head actually.
I am thinking about cutting that end shorter to get the flange - after crushing the copper washer - to sit directly on the head.

Is there a trick to mac exhausts or anybody has experience with it?

Thanks!

did you get this pipe used?...did it come with the allen head bolts?...cuz any others might not be long enough...just to be clear, the original spigots will be removed and not used.  I would worry that cutting those flanges shorter would cause the pipe to not clear/line up somewhere else...was hoping this pic was more of a detailed close up, but it hopefully might help

[70CB750]

The problem i see is that with the pipes in place there is almost an inch between the flange and the head. On every exhaust flange i ever saw the flange bolted down to the head with no space between.

It is like i cant get the pipe in the head deep enough.  Will post pictures.

[Dimitri13]

Make sure you've removed the old exhaust gaskets. They can blend it.

[Really?]

If you bought it used and it did not come with the rest for the centerstand, they have them at cb750supply.com

[dhall57]

Here's a pic of the mac pipe mounted on #1 cyl.

[70CB750]

Thank you, sir. Thats exactly what have me confused. I was expecting the flange to sit on the head port.

[madmtnmotors]

The flange is not designed to fit flush, it merely provides the clamping force. Studs with nuts are recommended, that way the force on the aluminum threads in the head are merely a pulling force, since bolts exert pulling AND twisting/shearing forces as they are torqued.

[70CB750]

Got it, thank you!