Author Topic: Need help understanding these exhaust pipes. 1978 cb750k  (Read 771 times)

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Offline mycoal

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Need help understanding these exhaust pipes. 1978 cb750k
« on: December 16, 2015, 07:45:17 PM »
So I have a 1978 cb750k. I bought these exhaust pipes off ebay a few years back from a guy selling them as 1973 cb750K pipes. He told me that they were actually from a later year cb750k sohc and that they'd fit my bike. I think he said they were off of a 77-78. At the time I believed him because the top of the headers (where they fit into the engine's exhaust ports) looked legit. However. Trying to get these on my bike has been a pain in the dick. The headers fit on no problem with the flanges and crowns. But I cannot for the life of me figure out how the mufflers are supposed to go on and slide onto the end of the headers.

I've seen other pictures of these that look almost identical (4 into 2 megaphone pipes) the mounting tabs are all the same and it just won't go that way on my bike. Theres like a downward angle and no modified bracket can remedy that. Here are some pictures so you guys can see what I'm talking about:





On that first image you can see that downward slope on those mufflers. I've tried flipping the mufflers upside down and awkwardly mounting them that way and its just still no good. Any ideas?
« Last Edit: December 16, 2015, 08:31:29 PM by mycoal »
1978 CB750K with 1977 GL1000 front end

Offline BPellerine

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Re: Need help understanding these exhaust pipes. 1978 cb750k
« Reply #1 on: December 17, 2015, 05:34:31 PM »
they look like they should mount with the mufflers upswept somewhat like the mac version of them.bill
1978 CB 750K ard and webers
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Offline mycoal

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Re: Need help understanding these exhaust pipes. 1978 cb750k
« Reply #2 on: December 17, 2015, 06:00:39 PM »
I agree. So the mounting tabs need to be cut off and welded back on? Or some kind of hokey bracket needs to be jerryrigged?
1978 CB750K with 1977 GL1000 front end

Offline flybox1

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Re: Need help understanding these exhaust pipes. 1978 cb750k
« Reply #3 on: December 18, 2015, 01:45:30 PM »
I agree. So the mounting tabs need to be cut off and welded back on? Or some kind of hokey bracket needs to be jerryrigged?
+1
Cut the tabs. Install the pipes. Fab/weld new tabs to fit.
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"