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Author Topic: Holes in exhaust.  (Read 1393 times)

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Offline Jarrett_Honda

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Holes in exhaust.
« on: April 13, 2017, 03:28:15 PM »
I just can't catch a break. All four of my pipes on my cb750k5 have cracks or holes in them. #2 is stuck on the bike so I couldnt take them to a welding shop to see if they able to be patched up. The holes are causing back firing.

Would a welder be able to patch up damage like this? Would it be too expensive? Should I just go the JB weld route?

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Offline 540nova

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Re: Holes in exhaust.
« Reply #1 on: April 13, 2017, 04:00:45 PM »
I would say that exhaust is toast.


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Offline disco

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Re: Holes in exhaust.
« Reply #2 on: April 13, 2017, 04:27:22 PM »
I agree with Nova. You're prob only seeing the 'tip of the iceberg'. I bet the insides of that exhaust are rotten. Personally I would stump up some hard earned $ for a Delkevic exhaust. They're stainless steel & they sound awesome! Surprisingly well priced too.
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1976 CB750 K6 Sapphire Blue
1972 CB750 K2 836 Orange Sunrise
1972 CB750 K2 Candy Red
1972 CB750 K2 Candy Gold'

Offline calj737

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Re: Holes in exhaust.
« Reply #3 on: April 13, 2017, 08:43:28 PM »
Burnt toast, I'm afraid.  :(
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Stev-o

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Re: Holes in exhaust.
« Reply #4 on: April 13, 2017, 08:47:53 PM »
+1 toast.   You could try to find someone to braze it, I've had no luck finding anyone. 
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'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline Jarrett_Honda

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Re: Holes in exhaust.
« Reply #5 on: April 13, 2017, 08:48:09 PM »
I'm heartbrokern now.

R.I.P original CB750k5.

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Offline Stev-o

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Re: Holes in exhaust.
« Reply #6 on: April 13, 2017, 08:56:52 PM »
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'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline Don R

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Re: Holes in exhaust.
« Reply #7 on: April 13, 2017, 10:58:59 PM »
 I bought 2 bikes with 341's and got 2 good pipes out of the 8. One #4 looked really nice but while taking it off the muffler broke off in my hand.
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Offline PeWe

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Re: Holes in exhaust.
« Reply #8 on: April 14, 2017, 12:16:00 AM »
Find another exhaust of your choice. 4-1, 4-2-1 or 4-2. Delkevic make low cost pipes.
New replica cost some. If going for a replica, buy the HM300 version with larger diffusors to run without. Nice sound and less restricted than HM341
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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 Jarrett_Honda

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Re: Holes in exhaust.
« Reply #9 on: April 14, 2017, 12:35:54 AM »
Quote from: PeWe on April 14, 2017, 12:16:00 AM
Find another exhaust of your choice. 4-1, 4-2-1 or 4-2. Delkevic make low cost pipes.
New replica cost some. If going for a replica, buy the HM300 version with larger diffusors to run without. Nice sound and less restricted than HM341
Yeah the 300 series pipes are so rare. Like a unicorn.

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Offline PeWe

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Re: Holes in exhaust.
« Reply #10 on: April 14, 2017, 01:34:07 AM »
 Replica, can be found at several sites, not only yamiya750.com


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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 atm cycles

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Re: Holes in exhaust.
« Reply #11 on: April 14, 2017, 06:09:58 AM »
I've had repairs done extremely well. Rig welded with stainless patch and rod  polish out and virtually unnoticeable when mounted. That said you have to weigh the cost of repairs. Both times I've had pipes repaired they were very nice 300s. One had the muffler cracked off from header. Another had rust hole on muffler at header.
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