Author Topic: Honda SOHC cb750 Engine #582 Challenge Question?  (Read 2878 times)

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Offline RAFster122s

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #50 on: November 30, 2022, 01:15:11 PM »
John, congratulations! Happy you have been able to separate them after so much frustration. Now you can repair the fins and give everything a good cleaning and refinish before reassembly/rebuild.
Enjoy those drinks!
David- back in the desert SW!

Offline Don R

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #51 on: November 30, 2022, 01:20:31 PM »
 I'm sitting here smiling! Way to go John.
No matter how many times you paint over a shadow, it's still there.
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Offline BenelliSEI

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #52 on: November 30, 2022, 01:48:59 PM »
I'm sitting here smiling! Way to go John.

Thanks Gentlemen! Pretty pleased myself. Will post some photos of what worked, tomorrow.

Offline MauiK3

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #53 on: November 30, 2022, 01:58:33 PM »
Great job, perseverance pays!
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Offline BenelliSEI

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #54 on: November 30, 2022, 02:55:05 PM »
Great job, perseverance pays!

Thanks! You will appreciate this “was keeping me up at night”! Next step is to strip the head and get both lumps out for hydro blasting. I’ve never managed to get these parts really clean before painting. Interested to try this for the first time.....

Offline Alan F.

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #55 on: November 30, 2022, 06:29:09 PM »
That's great news, You're a Winner. Enjoy a few beverages with your Chicken Dinner!

I was wondering about some sort of plate mounted to the studs but I didn't spend much time thinking about it before something else came up. I'm sure your solution will benefit a quite a few of us down the line.
Cheers!

Offline HondaMan

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #56 on: November 30, 2022, 07:06:44 PM »
Bravo!
:)
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

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Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
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Offline BenelliSEI

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #57 on: November 30, 2022, 08:30:40 PM »
Thanks all! I’ll post some photos before I dismantle it tomorrow.....

Offline PeWe

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #58 on: November 30, 2022, 08:33:12 PM »
Good news John!
How long are the dowel pins?
Different diameters, holes and pins than later models?
Or just "welded" together by corrosion.
Tomorrow is here ;)
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 BenelliSEI

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #59 on: November 30, 2022, 08:59:03 PM »
Good news John!
How long are the dowel pins?
Different diameters, holes and pins than later models?
Or just "welded" together by corrosion.
Tomorrow is here ;)

PeWe..... no real corrosion to be seen. Just never been apart for +50 years. I’ll post photos next time.

Offline ekpent

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #60 on: November 30, 2022, 09:04:31 PM »
Suzuki GT750 Water Buffalo's are know to have a problem with corrosion pulling the barrels off and a lot of guys need to make a plate for it like this one.  https://www.oldjapanesebikes.com/blog/2009/07/24/the-puller/

Offline RAFster122s

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #61 on: December 01, 2022, 06:17:55 AM »
The Honda S90 and CT90 are a pita to split the engine cases and require you to fabricate a jig to do it. Vertical split. They can be difficult to separate.

Usually the CB motors are a dream by comparison...

Saw a bit about Cummins diesel motors where they use dowel pins to locate the transmission to the block and apparently you have to go up a size in dowel pins everytime you split the tranny from the block. The bell housing has to be located with runout gauges and it sounds like a major pita. Glad I don't play with Diesel motors...
David- back in the desert SW!

Offline Don R

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #62 on: December 01, 2022, 10:44:15 AM »
 I took a pass on buying a GT750 because of it being stuck and this cylinder issue.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline BenelliSEI

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #63 on: December 01, 2022, 12:53:31 PM »
So here’s the lifting rig that finally popped the barrels loose. Torqued it up as tight as I dared (the bed frame angle iron was actually starting to bend slightly, where the all thread picks it up). Poured the heat (paint stripper gun) to the area under each front end stud, where the locating sleeves are. Then a few good whacks upwards with a long brass drift and a 2.5 lbs. hammer! Phew.

Note: I used the flanged nuts, upside down on the top of the studs, to prevent the 2” X 6” lumber from pulling down into the stud tops.
« Last Edit: December 01, 2022, 08:24:44 PM by BenelliSEI »

Offline BenelliSEI

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Re: Honda SOHC cb750 Engine #582 Challenge Question?
« Reply #64 on: December 30, 2022, 04:53:58 PM »
Can I [be honored] to send you a couple of the thicker O-rings you'll need inside the 2 oil ports in the head gasket when you bolt it all back up?

Mark..... picked up a few days mail today and received the “0” rings, as promised. VERY much appreciated! Thank you and HAPPY NEW YEAR!