Author Topic: Exhaust Question  (Read 438 times)

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Offline scubanerdnick

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Exhaust Question
« on: August 04, 2023, 08:13:55 AM »
Will a 4 into 2 exhaust from a 79 CB750k be compatible with a 1978 CB750K model?

Offline TwoTired

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Re: Exhaust Question
« Reply #1 on: August 04, 2023, 08:46:56 AM »
Doesn’t seem likely.  79 was DOHC not SOHC in the USA.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline willbird

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Re: Exhaust Question
« Reply #2 on: August 04, 2023, 08:47:20 AM »
I thought it was a great question and I did a quick google. The 79 is a DOHC and the 78 is SOHC ? Folks are saying that the DOHC is significantly taller engine top to bottom than the SOHC.

Offline scubanerdnick

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Re: Exhaust Question
« Reply #3 on: August 04, 2023, 08:56:11 AM »
Thanks everyone.  I assumed that was the case but wanted to poll the experts before making a poor decision.  Thanks!

Offline PeWe

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Re: Exhaust Question
« Reply #4 on: August 04, 2023, 09:00:41 AM »
I think that Vance & Hines 4-1 for the DOHC CB750 has been used on CB750 SOHC.
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 scubanerdnick

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Re: Exhaust Question
« Reply #5 on: August 04, 2023, 10:50:49 AM »
Appreciate the comments.  I saw a 4 into 2 exhaust from a 79 CB750 on Ebay and wondered if it would fit my 78 K8.  I don't need it as I have a 4 into 1 but thought it might have been good for the right price.  Glad I didn't get too excited and bid on it only for it to not work.