Author Topic: Building a Custom Exhaust: Cylinder 1-4 Orientation  (Read 2806 times)

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Offline PeWe

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #50 on: May 04, 2023, 08:24:05 PM »
See comment #46 upper 2 pics that show the 4-1 with similar design of attachments as yours.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Ellz10

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #51 on: May 05, 2023, 09:25:25 AM »
So is the flange on your system captured by a swaged portion of the tube? If so, the “gap” around that tube at the flange is irrelevant. There should be some small clearance between the tube OD and flange ID.

So first pic is of my exhaust. Second pic is of Pewe's pic and I circled the area that I was confused about, but now understand that that gap is supposed to be there.
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Offline Ellz10

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #52 on: May 05, 2023, 11:46:53 AM »
Should I be torque'ing these M8 bolts to a certain specification?

I did just as Pete had instructed, even amounts on both bolts, all the way in until it was very tight. I can't say that I felt any kind of "give" that would suggest the copper gasket got crushed, but perhaps I just didn't feel it. How much pressure does it usually take to crush them?

I don't want to screw anything up this far into everything, so I'm asking for some advice here.

If there's a set torque value I should/could attain then that would be best so that I can be sure of things. I suppose I could always  remove one of the flanges to see if the gasket got crushed.
« Last Edit: May 05, 2023, 01:39:34 PM by Ellz10 »
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Offline PeWe

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #53 on: May 05, 2023, 01:41:12 PM »
Better to compare with same type of design.
The head pic is Hindle spigots, probably not tightened.

The other system have same design. The height of the thicker part must create a gap for flange, if not it will not seal.

Torque not important. You'll feel when copper crush washer start to give after as I wrote earlier.
Tighten too hard, the flange can be bent.


EDIT:
Height of these are 36.5mm. 37mm would be better since the flanges bottoms ir very close out when bent a little
« Last Edit: May 05, 2023, 09:11:41 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Ellz10

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #54 on: May 05, 2023, 02:54:26 PM »
Well they're all bolted in and as I mentioned earlier, I didn't feel any sort of "give" that would indicate the gasket getting crushed. However, as I mentioned before, I'm just going to go ahead and remove one of the pipes, #4 probably, and see if the gasket did indeed get crushed. I've got several extra gaskets. That way I'll have a good feeling if the others got crushed as well, seeing as I bolted them all in with around the same amount of torque.
« Last Edit: May 05, 2023, 02:58:26 PM by Ellz10 »
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Offline Ellz10

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #55 on: May 05, 2023, 05:25:16 PM »
What you need to be very mindful of is the torque you are applying to the bolts puts stress in the threads in the head. Torque too much, and you will rip the threads out. That is why studs were used per stock.

So essentially just apply enough torque to crush the gaskets and then stop?


***UPDATE***

So I went ahead and unbolted the #4 pipe to get a look at the gasket and attached is what the gasket looked like. I obviously replaced it with a new gasket and went ahead and torqued it to what I had it at before I unbolted the pipe.

Thoughts on the looks of it? Should it be crushed more or does it look about normal?
« Last Edit: May 05, 2023, 07:22:18 PM by Ellz10 »
Thankful for everyone on this forum. Grateful to continue to learn so much.



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Offline Ellz10

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #56 on: May 05, 2023, 07:53:09 PM »
Looks fine. Torque to that strength and stop.

I did! Then I got the torque wrench out just to see what the value was at and they were all roughly 12 ft lbs of torque! Now I know. I'll be sure to update this thread when I get her all started up and make sure there's no exhaust leaks!
Thankful for everyone on this forum. Grateful to continue to learn so much.



'77 K7 - http://forums.sohc4.net/index.php/topic,193043.msg2251436/topicseen.html#new

Offline PeWe

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Re: Building a Custom Exhaust: Cylinder 1-4 Orientation
« Reply #57 on: May 05, 2023, 09:15:05 PM »
That look good.
I reuse the washers if removing the exhaust. No leaks when not overtightened  before, just as much as needed.
Antiseize helps to save those threads.
Removing exhaust should not happen that often unless frequent rebuilds and redos.
Oil filter change must be possible with exhaust on.

The Hindle design with spigots make exhaust removal without untifhten bolts.
« Last Edit: May 05, 2023, 11:06:23 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967