Topic: Stock CB750 4 in 4 installation question

[mycb750k6]

I have a 71 CB750 that I removed the kerker from and am about to install stock pipes. After some amount of effort I located a set of exhaust flanges and bolts. I did a test fit and am wondering about the thickness of the copper exhaust gaskets. Do these rings compress a great deal when tightened down? Seems like they must flatten out in order for the fit of the flanges to be correct and having done that they probably can't be used again? I didn't see any copper gaskets in there when I pulled the kerker. Did it require them and I'm just not seeing them? Finally, how to torque down the flange bolts? I've read many stories about how these are impossible to remove once installed. Should I use anti-seize on the threads, grease? When tightened down should the flanges be flush with the mating head?

[333]

Yes, they compress.  They are the gasket.  Sometimes the old ones are hard to see, and have to be dug out.

[Gordon]

It's almost a guarantee that there are old gaskets already in there.  This subject comes up almost weekly where somebody swears there are no gaskets in the exhaust ports, we tell them to look closer and gently pry around in there, and sure enough they were in there.  The get squished completely flat and covered with carbon so they blend in with the rim of the port.  

On one of my previous bikes there were actually two sets of old gaskets in the exhaust ports because the PO didn't realize the first set was already there and put another set on top. 

[mycb750k6]

OK so the Kerker definitely used the same copper gasket? Otherwise it probably would have been leaking? For all I know there could be a dozen in there.

[Gordon]

OK so the Kerker definitely used the same copper gasket? Otherwise it probably would have been leaking?

Correct.

[Johnie]

Yes, the old ones are covered with carbon and that is why you can not see them.  The pic below will give you an idea of where they are.  Click the pic...

[mycb750k6]

Well they were right there where you said they'd be but it did take some digging to get them out.

Second part of question is how much force to use when putting exhaust spigots back in?

[Johnie]

Well they were right there where you said they'd be but it did take some digging to get them out.

Second part of question is how much force to use when putting exhaust spigots back in?

Just put the gaskets in place and then screw down the exhaust flanges.  Tighten the screws a little at a time on each so the flange goes back in straight.  I tighten them as tight as I can with a large screwdriver. 

[mycb750k6]

Got it, hurray almost done.

[petercb750]

When I put the new exhaust on mine, I found I had to check the flange screws and collar bolts now and then and nip them up, but all has settled down.
BTW, sweeeeeet looking bike mate. Don't new pipes make a difference!

[Johnie]

When I put the new exhaust on mine, I found I had to check the flange screws and collar bolts now and then and nip them up, but all has settled down.
BTW, sweeeeeet looking bike mate. Don't new pipes make a difference!

Agree...nice looker there!!!

[Zaipai]

Nice looking ride to be sure. Its good that its almost done..

[bucky katt]

i use a pick tool to get the old gaskets out
just be careful you dont gouge the aluminium