Author Topic: Resto for cb750k8  (Read 8657 times)

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Offline denward17

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Re: Resto for cb750k8
« Reply #75 on: January 28, 2025, 04:01:06 AM »
Looking great!  good progress.

Offline Dime

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Re: Resto for cb750k8
« Reply #76 on: January 28, 2025, 04:38:20 AM »
Great job!

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Offline letmwhirl

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Re: Resto for cb750k8
« Reply #77 on: January 28, 2025, 11:36:45 AM »
Just had enough time this afternoon to lap the valves and assemble.

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #78 on: January 29, 2025, 12:21:15 AM »
Wednesday and another rainy, dreary weather day in Germany. But a great day to spend time in the garage on my favorite project. Resto for cb750k8. This has been a great opportunity for me to reminisce the occurance when I purchased a 1973 cb750 new off the showroom in Houston, TX. One week later I purchased a Yoshimura cam and piston kit along with a kerker 4into1 exhaust. I was so happy and what fun it provided. To be honest, I cannot even remember what happened with it. did I sell it or trade it? no idea. But this project brings back the memories and excitement I had back then.

Today, I will try to get the cylinders and head installed. If all goes to plan, maybe even adjusting the valves. By this weekend, I hope to have the stand built to hold the motor on my mobile diy bench. I plan to hoist the frame from the garage joists and manuever it sideways over the motor. It should be a much easier process than others I have witessed on YouTube. The only down side is time to build the motor stand and then, what do I do with it once the project is over. Since it is built from welded 2 to 3mm square steel tubing, I will likely just cut it into pieces and be used in other projects down the road. I will take pictures of the stand along with the frame hanging before and after that step in the effort.

Currently the frame and a few other items are sitting on the mobile bike bench. These will have to be removed in preparation for the engine stand and engine to be placed. Also, at the moment the engine is being built on top of a 2nd mobile bench in my garage extension. Explaining this now helps me plan and prepare for what's coming. I hope you don't mind. We have a small 2 car garage 5meter by 7meter, then I added a 5m x 5m extension onto it. So on motor insertion day,, all cars will be out on the driveway, the cb motor will be hoisted and bolted to the motor stand, the bike bench will be rolled under it and positioned. Then the frame will be hoisted and engine bench rolled into position for the frame manipulation over the engine. 

If you have read to this rumbling, I applaud you and want to thank you as well. Any suggestions before final assembly of the motor or it's frame installation, please comment. I will have time every evening to gleen your comments and suggestions.

A little info on my early life... my father was an automatic transmission builder, I learned from him. He had a few shops in the Houston TX area where I gained some experience. But later I worked for 30 yrs in other occupations. While working with my father, I also rebuilt engines and transmissions. This is the background for what got me into this project predictament.  :o

Offline newday777

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Re: Resto for cb750k8
« Reply #79 on: January 29, 2025, 03:23:24 AM »
Still following along with your progress 👍.
It's snowing here in NH so I'll be down in my warm shop today in a couple hours doing some carb cleaning for a friend.
So your garage is @16'x39' with the extension? Mine is a little smaller @12'x36' in the basement of the barn where I live. It sure would be nice if my shop was another 4' wider, but then I'd probably just stuff more bikes in it.....
I installed a pellet stove a couple years ago which helps fend off the moisture that weeps through the old stone foundation occasionally in rain.
How long have you been there in Germany?
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline denward17

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Re: Resto for cb750k8
« Reply #80 on: January 29, 2025, 05:10:38 AM »
To help with engine install, you could grind and repaint this mounting point so the engine will have a little more clearance to slide in.


Offline MauiK3

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Re: Resto for cb750k8
« Reply #81 on: January 29, 2025, 06:47:26 AM »
Having a warm shop is a joy when it's cold outside
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Stev-o

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Re: Resto for cb750k8
« Reply #82 on: January 29, 2025, 06:54:58 AM »
Wednesday and another rainy, dreary weather day in Germany.
This has been a great opportunity for me to reminisce the occurance when I purchased a 1973 cb750 new off the showroom in Houston, TX.

Wednesday and another rainy, dreary weather day in Texas today!

I lived in Houston in the 80's, but I had a Kawasaki 1000 back then in the Alief area, good memories...
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #83 on: January 29, 2025, 09:37:43 AM »
To help with engine install, you could grind and repaint this mounting point so the engine will have a little more clearance to slide in.
Yeah, I also saw this on another post… but too late. I already have the frame powder coated. So I will have to take it slow … just like a retiree… cuz I am one….

Here is a link to the motor stand, which I will attempt to copy…. https://www.dotheton.com/index.php?threads/sohc-cb750-engine-install-stand.31317/

Seriously, thank you for the suggestion and hanging in there on this project post. Today I made some more progress.

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #84 on: January 29, 2025, 09:54:20 AM »
Still following along with your progress 👍.
It's snowing here in NH so I'll be down in my warm shop today in a couple hours doing some carb cleaning for a friend.
So your garage is @16'x39' with the extension? Mine is a little smaller @12'x36' in the basement of the barn where I live. It sure would be nice if my shop was another 4' wider, but then I'd probably just stuff more bikes in it.....
I installed a pellet stove a couple years ago which helps fend off the moisture that weeps through the old stone foundation occasionally in rain.
How long have you been there in Germany?
My garage is 16x23ft with a 16x16ft extension. Sure wish I had a oven in my garage. These 0 celsius days are tough. but I do have a small propane heater, which I turn on and off throughout the day.
My now wife moved to the states in 1998. I met her in 2003 and we stayed together ever since. Married in 2006 and moved here in 2013. We had visited a few times and I really enjoyed the cooler weather and the green vegetation everywhere. Yes the winters are long and mostly wet.. but we have 4 seasons and I find it very pleasing.  Glad you are hanging in there with me on this one.

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #85 on: January 29, 2025, 10:07:12 AM »
Today I was able to get the cylinders and head installed. My wife came out and held the timing chain while I positioned the cylinders and then the head in place. I took it very slow with the cylinders sliding over the pistons since I use no ring squeezers. First I placed two 1/2“ drive extensions under the #2 and #3 pistons, then worked with the rings to line them up and it only took a few minutes to get ready for the outside two pistons. The two outside pistons went even quicker. The head was also no problem. I ran out of time and will hopefully finish with the rocker arms, timing, valve adjustment and cover by tomorrow. I need to start with the engine stand before the weekend. for that I will pickup some 1meter pieces of 3cm square steel tubing. Then cut and weld it together. Photos surely will be posted after the stand is ready.

Offline RAFster122s

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Re: Resto for cb750k8
« Reply #86 on: January 29, 2025, 11:24:36 AM »
Hang your stand somewhere out of the way if you think you will have another cb750 in the future. Many have fabricated a large C shaped hook to strap to the motor to fit it into the frame, works well I am told and from what I have seen.

Another technique is to block the motor on its side and lift the frame down over the motor. Frame has to be stripped down pretty bare for weight to be manageable, but a few have done it with wheels and forks attached and it is a fairly simple thing to right the bike up to vertical then…

Nice work on your rebuild!
David
David- back in the desert SW!

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #87 on: January 30, 2025, 12:19:47 AM »
Hang your stand somewhere out of the way if you think you will have another cb750 in the future. Many have fabricated a large C shaped hook to strap to the motor to fit it into the frame, works well I am told and from what I have seen.

Another technique is to block the motor on its side and lift the frame down over the motor. Frame has to be stripped down pretty bare for weight to be manageable, but a few have done it with wheels and forks attached and it is a fairly simple thing to right the bike up to vertical then…

Nice work on your rebuild!
David
A C-shaped hanger for the motor also sounds simple and effective. I like the idea. And possibly less to hang on the wall. Does anyone have photos? I would really like to see one in action or just a photo with dimensions. I can also imagine this might even be better, because you are maneuvering the motor and not the frame, therefore one might be even more focused on its positioning.
Great tip.  But I will avoid lying the motor on one side method as a last resort. I watched the Spanner Rash YouTube video where they tried this method. He does nice work otherwise but that installation of a SOHC 4 gives me horror.
Great Tip David and thanks for the comment on my current build.

Offline newday777

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Re: Resto for cb750k8
« Reply #88 on: January 30, 2025, 06:53:27 AM »
I've seen several different versions of the C hook.
I like this one that you use straps to secure it to the engine.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline newday777

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Re: Resto for cb750k8
« Reply #89 on: January 30, 2025, 06:55:37 AM »
This can be cut out on a CNC if you have one and a piece of 1/4" plate to sacrifice.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline newday777

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Re: Resto for cb750k8
« Reply #90 on: January 30, 2025, 06:58:44 AM »
And some other variations
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #91 on: January 30, 2025, 09:36:47 AM »
I've seen several different versions of the C hook.
I like this one that you use straps to secure it to the engine.
You really went the extra mile. Thanks a million for the photos and info. I cannot see the measurements in the photo, but I will try something tomorrow based on what you have suggested. Very happy you gave me this idea.

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #92 on: January 30, 2025, 09:54:08 AM »
Today, I was able to complete the engine assembly. The only things to finish are the starter and the carbs, both can go on after the engine is bolted in.  I sealed the pucks with minimal Hondabond, installed the cam/rocker saddles, then was able to get the cam timed and caps and screws torqued. I adjusted the rockers and installed the cam chain tensioner. The valve cover was fastened after a new rpm cable seal and the gear was installed. A little clean up and the wife called for dinner. Life is good.

Offline denward17

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Re: Resto for cb750k8
« Reply #93 on: January 30, 2025, 10:51:48 AM »
Great job!

It has been mentioned is this forum it is a good idea to loosen head nuts/bolts in the correct order and re-torque after 24-48 hours, supposedly to help with head gasket leaks.

Offline Don R

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Re: Resto for cb750k8
« Reply #94 on: January 30, 2025, 02:56:40 PM »
 I always like to see the cam timing after the tensioner has been re-installed and adjusted. Just in case all of the slack was going the wrong way.
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Offline letmwhirl

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Re: Resto for cb750k8
« Reply #95 on: January 31, 2025, 12:07:48 AM »
Great job!

It has been mentioned is this forum it is a good idea to loosen head nuts/bolts in the correct order and re-torque after 24-48 hours, supposedly to help with head gasket leaks.
Glad you mentioned it now. I will take care of this today. Thanks for the tip!!

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #96 on: January 31, 2025, 12:13:28 AM »
I always like to see the cam timing after the tensioner has been re-installed and adjusted. Just in case all of the slack was going the wrong way.
I was very concerned about this after first aligning the chain and sprocket. But it is dead on after several rotations after tensioner install and during valve adjustment. Thanks for mentioning.

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #97 on: January 31, 2025, 12:22:05 AM »
Today will be a little colder. But I want to attempt a go at the C hanger for the engine install. It can be that the metal I purchased yesterday is not strong enough to support the weight. My square tubing is 3mm thick and 3cm square. We‘ll see.

The photo is from the back of my house and through the balcony door. Second photo of weather app for today.

Offline newday777

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Re: Resto for cb750k8
« Reply #98 on: January 31, 2025, 05:23:03 AM »
I would suggest to go with 6mm thick, 5cm square (or rectangular 3cm x 5cm)
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline letmwhirl

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Re: Resto for cb750k8
« Reply #99 on: January 31, 2025, 11:21:38 PM »
Yesterday, going down to the garage, I had my mind made up to make the C-Hanger, but them I watched the video ,,, and decided on method used on DoTheTon.com.  I built it using mostly 3cm square tubing and a couple pieces of 2.5cm square tubing. I cleaned the welds on the base of the stand and left the others for later grinding.

The motor was attached and hanging without additional support 1.5 hrs ... no problems. However, I will not install the frame over it until Sunday, so I added a couple boards under and one off the end of the highest horiontal hanger. It has to be safe for over 32 hours,, before another pair of hands are here to help with the install.

The bolts are lying ready, I was thinking of installing the coils and will look into that today. I think they are easier to install before the engine is in place. PLEASE let me know today if there is anything else which would be best to take care of before the engine goes in. Currently, the frame is bare.

I will add a couple photos from my phone.