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Discussion Starter #1
Can anyone help me out with a problem I'm faced with for putting my headers back on the block of my twin CB350?

I have four sleeves (2 for each header) that I set aside after taking my exhaust off. When I went to put them back on, I couldn't get the header forced against the (new) copper crush ring and block with the flange.

I noticed that the sleeves might not be long/deep enough to force the header back. I also noticed that I have 3 sleeves that are identical and 1 that is a little shorter and thicker. Any advice? I cannot find specs on this part and I'm not sure how else to reassemble the exhaust.

Thanks,
 

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Same headers? Were they tight before you took them off? Honda used two different length keepers - the early 350 used longer ones with a thin header flange, and the later models used short ones with a wide header flange (more like a sleeve). Your keepers look like the short ones. What do the end of your headers look like?
 

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Same headers? Were they tight before you took them off? Honda used two different length keepers - the early 350 used longer ones with a thin header flange, and the later models used short ones with a wide header flange (more like a sleeve). Your keepers look like the short ones. What do the end of your headers look like?
Here are what the end of my headers look like. I don't remember if they were tight when I took them off but wouldn't they have to be to crush the exhaust gasket evenly when you tighten the nuts on the studs? With the collars I have, the headers wiggle around loose with the stock flanges.

Honda OEM Part Number 18233-318-000 for reference.
1972 CB350K
 

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Unfortunately, you need the longer ones. Search for pics of them on line and you'll see the two different lengths.
 

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Do the sleeves go flange end in or out???
They may tighten better if you turn them around???
 

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Flange out, it fits into recess machined in collar. easy way to hold them in place is painters tape (I don't use anything but I've pulled apart a lot of bikes that have used it)
 

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I asked because some of the photos seem to show the flange turned in???
 

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Those last pics are just the header flanges. Shallow flanges = long keepers. The keepers are placed correctly in the very first picture, but are too short to allow the finned exhaust collar to tighten down sufficiently.
 

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Discussion Starter #10
Well I wish I knew how the hell they went on while the bike ran! I'm pretty confident that these are the ones I pulled off earlier in the project. I fabbed up some new ones that might work by welding a steel ring to a pipe and cut it in half. Worst case Ontario, I'll order the ones I need... Thanks for the advice @83XLX
 

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Look at the gap on the far pipe - this is approximately how it should look when tightened down with fresh copper gaskets. Hope you get it sorted out.
B182FA5C-5168-4FE6-BEDF-83058EF4C5F9.jpg
 

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Was there more than one copper crush gasket in there when you took it apart.

That may have filled up the space and made it so the shorter sleeves fit.

The Longer ones are available

CMSNL Has them I think.
 

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