Author Topic: 1970 CB750 project "Dad's bike"  (Read 6247 times)

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Offline ECM

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1970 CB750 project "Dad's bike"
« on: March 12, 2015, 09:32:10 PM »
I'm new to the forum and am starting down the road of rescuing my dad's 1970 CB750.  He bought the bike new while on tour in Vietnam  (Navy), actually he ordered two CB750's (one Blue/Green and the other Candy Orange) because the price was so good.  In the end he only took delivery of the Blue/Green because the dealer later contacted him saying he couldn't offer the Orange one at the same great deal, so my dad canceled the order on the Orange bike even though it was his preferred color. 

He had a friend pick up the bike delivered to California in the summer of 1970 while he was still on tour.  The VIN plate has a build date listed as 6/1970. 

He rode the bike for many years and put just over 36,000 miles on it before he stopped ridding it in 1984.  I was 8 years old at the time.  It was the first motorcycle I ever rode on and even now I remember that ride. 

During those years of riding he added his own "improvements" to the bike and repainted it Black.

From 1984 on it sat on the side of his house, never started or cared for.  At one point he tried starting it and noticed it wouln't kick over.  It was siezed up somehow.  That led to it sitting some more.  In 2009 he asked me if I would like it.  Of course I said sure even though my dream had always been his 1967 Corvette that he also bought new just before joing the service.  But the Corvette was not to be had yet.  So the Honda was mine.

When I got it home I put it in my garage and there it sat for another year untouched.  After all I had baby boy who was 1 at the time and working on a seized up, corroded motorcycle was far from a priority for me. 

One night in 2011 I had a friend over to watch a F1 race and we had a few beers.  Well let's just say we got motivated and ageed that night that we should pull the engine out of the Honda.  I still don't remember the details of how we did it but it came out with no damage. The engine was put on a cart and there it sat for another year. 

In 2012 I now had a 5 year old son that was curious about how engines worked so I thought it would be a great opportunity to pull the engine apart.  I learned quickly that dealing with a seized engine wasn't nearly as fun or educational for a 5 yr old.  Progress was so slow both my son and I found other things to entertain us and the bike sat again.

Now all that brings us to now. In February of this year, 2015, I got a total wild hair hair up my ass to get this project going.  And like my wife says when I decide to do a project I go at it and drain our bank accounts.  So there my wife was rolling her eyes and I started reasearching the history, cost of parts and tricks of the trade.  (So acetone and ATF is a great penetrating oil? Who would have thought)

Now I am into the tear down and really excited about what the final product will look like.  I am no master mechanic so I will have a lot of learning to do along the way.  I already bought Mark Price's book on bringing them back from the dead and it is giving me a lot of confidence about what that next bolt holds on or under that cover.

I will be documenting the project here so bare with me.  Sorry if this was a long introduction but I thought for documentation purposes it would belong.  The goal I set for myself was initially aggressive to be done with this project.  I thought if I could take my son on ride with it when he is 8, the same age I was when I first rode on it than that would be neat.  So I have a little over one year to make that happen.  We will see.

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #1 on: March 12, 2015, 09:39:43 PM »
Here are pictures of the bike as I started documenting the project.  (Feb. 2015)


Offline goldarrow

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Re: 1970 CB750 project "Dad's bike"
« Reply #2 on: March 12, 2015, 09:41:16 PM »
Great stories.  Would like to see some pics, when it ran, when it sat, and how it is now.  After all project threads need lots of pics.    Welcome
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Offline Stev-o

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Re: 1970 CB750 project "Dad's bike"
« Reply #3 on: March 13, 2015, 05:14:35 AM »
Excellent story.  We're here to help so no putting this project on the back burner again.
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Offline calj737

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Re: 1970 CB750 project "Dad's bike"
« Reply #4 on: March 13, 2015, 05:28:56 AM »
Post your home address, that way, if you start slowing down on the rebuild, members can drive past and vandalize/torment you to guilt you into picking up the project again!

It would be interesting to know the engine series number and frame series. That's a pretty early build number, and being a 1 owner bike in decent enough condition, a quality restore could turn out a stunning bike for your son to own!

Remove the tank and fill it with Distilled white vinegar to commence the de-rusting process of it.

And do yourself a major favor, be highly organized and documented when removing pieces, parts and what not. Those "Phillips screws" on the engine and frame aren't Phillips, they're JIS and you need true JIS bits to remove them without tearing them up. If your effort will be to restore, then spend the money to buy the bits and save your time later. It makes all the difference in removing them.
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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 ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #5 on: March 13, 2015, 12:24:44 PM »
Here are a few more pictures prior to getting into it.


Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #6 on: March 13, 2015, 12:28:35 PM »
Here is picture of the VIN plate on the chassis.

Chassis number: CB750-1042590
Engine number: CB750E-1042779


Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #7 on: March 13, 2015, 01:07:31 PM »
Some other fun stuff that Dad gave me along with the bike:

1969 copy of Cycle World on the release of the CB750.  It is incredible shape.

Shop Manuals (Old and New)

Receipt for the bike.

Certificate of Origin


Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #8 on: March 13, 2015, 01:11:15 PM »
Now on to the tear down. 

I was able to mark the cam towers and rocker sequence.  Don't want to get these parts out of order.  As I have been told, be organized.


Offline calj737

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Re: 1970 CB750 project "Dad's bike"
« Reply #9 on: March 13, 2015, 01:12:44 PM »
That documentation is exceptional! Ziplock bags for all of it- what a great story and great heirloom to have. Huge envy for you!
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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 ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #10 on: March 13, 2015, 01:19:27 PM »
That documentation is exceptional! Ziplock bags for all of it- what a great story and great heirloom to have. Huge envy for you!

There's a lot more documentation as well, that is just the ownership stuff I thought was cool.  There are lots of letter's to and from the Dealer about issues getting it on-time, demand for the bikes, prices changing due to demand, lost shipment, even some Navy arbitration stuff to get the bike. 

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #11 on: March 13, 2015, 01:22:46 PM »
Got the head off.  Nasty looking.  Feeling a bit overwhelmed.  I guess it is time to fill the cylinders with the Acetone/ATF and let it sit.



Offline calj737

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Re: 1970 CB750 project "Dad's bike"
« Reply #12 on: March 13, 2015, 01:33:00 PM »
Been there, done that. Had to resort to more aggressive tactics ultimately...

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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 ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #13 on: March 13, 2015, 01:36:44 PM »
Been there, done that. Had to resort to more aggressive tactics ultimately...



Wow!!!  That has to be a method of last resort, right?  I know metal expand/contract with heat, but doing that to the engine is a bit scary.

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #14 on: March 13, 2015, 06:35:54 PM »
Now that the engine is "soaking" in ATF/Acetone I figured I could start taking apart the chassis.  It actually went pretty quick.  Just a lot of taking pictures and labeling zip lock bags of nuts and bolts and where they go.


Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #15 on: March 13, 2015, 06:47:54 PM »
I was amazed after getting the frame stripped just how rough the welds are.  Is that normal on these bikes? 

Now to divide things into piles.  One for powder coating, one for paint, one for chrome, one for polishing, and one for zinc plating.  I think this is where the money and waiting begins.

I am still not sure if I want to restore it to factory brand new, or do a little more custom.  My dad didn't keep it stock for long so if it was to be a tribute, than factory new isn't very important.  I have even started talking to my son about what the bike should look like.  Showing him pictures of the bike as it was brand new and some custom painted ones with a 4 into 1 exhaust.  It will have to be a two up bike and I want to keep the factory seat, but there is a part of me that likes the 4 into 1 exhaust and maybe slightly lower handlebars.  Factory new would be pretty cool too.

Opinions welcome on Factory look or slightly custom?  Pros/Cons?  Remember this bike will never be sold so this is more about feeling and look than what it would be worth.

Offline Restoration Fan

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Re: 1970 CB750 project "Dad's bike"
« Reply #16 on: March 13, 2015, 07:16:19 PM »
With 4-into-1, you're going to have an issue with the center stand in most cases. 
FWIW, the chrome is what's going to cost you the most.  Paint and even powder coating are reasonably priced but anything shiny costs more.  Before you pay to have something rechromed, check to see if you can buy a replacement piece somewhere.  Sometimes, you can buy a replacement part on eBay or Craigslist for cheaper than having a part rechromed.

However, you should know that a LOT of your shiny pieces can be polished.  Start by sanding with rougher grits and move to finer grit, then go to polishing wheels with rouges.  It won't be fast but it is intensely satisfying to see old, grubby parts come back to life and look new.
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Re: 1970 CB750 project "Dad's bike"
« Reply #17 on: March 13, 2015, 07:49:43 PM »
I was amazed after getting the frame stripped just how rough the welds are.  Is that normal on these bikes

Yes.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
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2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline mwvachon

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Re: 1970 CB750 project "Dad's bike"
« Reply #18 on: March 17, 2015, 07:44:30 PM »
Great thread, ECM. This is a great community to support your effort. I also restored my Dad's K1 750 that he bought new back in the day, so that was truly a labor of love as well. I was particularly thrilled to show it to him when it was completed. He has passed on recently, so I hold that bike very dear to me now. I also enjoyed rebuilding that one so much, I decided to do another one more recently. Now that the second K1 has been completed, I'm still on the lookout for yet another possible project. It can be addicting! Don't hesitate to ask questions - it's how we all learn about these great vintage machines.
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1999 Valkyrie I/S
1971 CB750-K1 (Candy Gold)
1971 CB750-K1 (Candy Red)
Project link: http://forums.sohc4.net/index.php?topic=108498.0]
1965 Honda S90
1976 GL1000
1975 CB400F

Offline 3457fl

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Re: 1970 CB750 project "Dad's bike"
« Reply #19 on: March 21, 2015, 01:19:26 PM »
Great story and project, keep the pics coming.

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #20 on: March 22, 2015, 01:29:39 AM »
Thanks for the kind words and the encouragement. I appreciate it.

Seems like I am at the point where everything needs to go out for powder coat and paint while continuing to work on the engine. I just have to make a firm decision on what scheme I am going to do. As you can see from the starting pics my dad had painted the bike black leaving the gold tank stripe. Maybe I will go with a Black and Gold theme but with a bit more detail.

Offline Johnie

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Re: 1970 CB750 project "Dad's bike"
« Reply #21 on: March 22, 2015, 05:25:20 AM »
Yes, great story. You mentioned opinions welcome - stock or slightly custom. You will get a lot of different ideas on that one. Me, I enjoy trying to take these bikes back to OEM as they came off the showroom floor. I like the challenge more than putting on new custom parts. Plus, how can you beat that look of the early 70's. It will cost you though if you go with OEM exhaust...or take the easy route and find some aftermarket to stick on there until you can find and afford OEM. Noted that chain guard is from a K1 bike as the end is longer. Honda changed from the short guard to a longer one on the K1 model to reduce oil from slinging up on the passengers legs. So your Dad must have changed that out at some point. Maybe he did not toss it out as those are costly and hard to find if you decide to take it back to stock.  But keep in mind it is your bike and do with it what you and your son will like for sure. You mentioned Dad ordered a blue/green and orange. The CB750K0 Four was available in one of three colors: Candy Blue Green, Candy Gold, or Candy Ruby Red. The tank, side covers, air box and upper forks were of the basic color (blue/green, gold, or red). The headlight shell was also the basic color. Good luck with this neat project and keep us updated on the progress.
« Last Edit: March 22, 2015, 06:47:34 AM by Johnie »
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #22 on: March 23, 2015, 07:50:08 AM »
Thanks for the thoughts. They are welcome.

I did not know the chain gaurd was from a K1. I will have to ask him about that. I know he didn't like muck getting on him as he also attached an aluminum shield to the chain guard that ran between the tire and the swingarm by the swingarm pivot and also a piece of rubber at the bottom of the rear inner fender down to the swingarm.

As for the exhaust I do have the original exhaust pipes as he had them. He fabricated a 4-1 of his own design shortly after getting the bike that allowed for the center stand and oil filter access. It ran down the left side of the bike something I haven't seen duplicated. It was just a glasspak welded to his header. It was really rusted out when I got the bike. The original exhaust is hanging in my garage. The only downside of it is the chrome will need a bit of polishing as it was also exposed to the outside weather all be it under an awning.

I do have the ability to go back to stock but there will need to be a lot of chrome polishing and new replacement chrome part that just aren't salvageable. So cost to go to stock I project would be higher.

No candy orange in a K0?  I have seen pictures of 1970 Candy Orange with the K0 emblem on the side covers and black Honda emblem on tank. Are we sure no K0's were made in Candy Orange?

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #23 on: March 23, 2015, 08:01:48 AM »
Maybe I am thinking Candy Gold not Orange

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Re: 1970 CB750 project "Dad's bike"
« Reply #24 on: March 23, 2015, 11:30:37 AM »
The good thing is that once you have decided you are not going to do a full restoration to assembly-line spec, you are free to make the bike what you want -- colors that were not offered on that year model or any year, improved performance and reliability modifications, in addition to the aesthetics.

Restorations are absolutely gorgeous, but some people are afraid to ride their fully-restored bikes after such a painstaking effort.  I don't blame them after all of that work, but I (personally) would rather have a bike I can ride and that is suited for my idiosyncratic needs. That's why I lean towards restomod builds.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #25 on: March 27, 2015, 08:27:36 PM »
Noted that chain guard is from a K1 bike as the end is longer. Honda changed from the short guard to a longer one on the K1 model to reduce oil from slinging up on the passengers legs. So your Dad must have changed that out at some point.

Talked to my dad last night and he said he has never changed the chain guard, that is the one that came on the bike.  So maybe this was one of those evolution pieces that happened mid year?.... 

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #26 on: March 27, 2015, 08:35:29 PM »
Pulled the collar from the swingarm today.  Odd colors?  Everything okay here? I don't feel anything abnormal with my finger. I found that my dad had put Bronze bushings in.  Not sure if I should remove these before sending the swingarm to powder coating?  (Powder coater said all bearing and races should be removed prior to Powder coating as they can really get jammed in there after the baking process never to be removed again)  If I do remove do they need to be replaced with new bronze bushings?


Offline Trad

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Re: 1970 CB750 project "Dad's bike"
« Reply #27 on: March 27, 2015, 08:39:34 PM »
That collar is in fantastic shape. No pitting or scoring.
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Offline CB750faces.com (Lecram)

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Re: 1970 CB750 project "Dad's bike"
« Reply #28 on: March 28, 2015, 03:10:04 AM »
Yes, great story. You mentioned opinions welcome - stock or slightly custom. You will get a lot of different ideas on that one. Me, I enjoy trying to take these bikes back to OEM as they came off the showroom floor. I like the challenge more than putting on new custom parts. Plus, how can you beat that look of the early 70's. It will cost you though if you go with OEM exhaust...or take the easy route and find some aftermarket to stick on there until you can find and afford OEM. Noted that chain guard is from a K1 bike as the end is longer. Honda changed from the short guard to a longer one on the K1 model to reduce oil from slinging up on the passengers legs. So your Dad must have changed that out at some point. Maybe he did not toss it out as those are costly and hard to find if you decide to take it back to stock.  But keep in mind it is your bike and do with it what you and your son will like for sure. You mentioned Dad ordered a blue/green and orange. The CB750K0 Four was available in one of three colors: Candy Blue Green, Candy Gold, or Candy Ruby Red. The tank, side covers, air box and upper forks were of the basic color (blue/green, gold, or red). The headlight shell was also the basic color. Good luck with this neat project and keep us updated on the progress.

Honda changed the chain guard from 1021880. I own two K0s (103... and 104...) and both have the long versions. The long K0 version is slightly different from the K1 chain guard, barely visible. So this guard should be right for this bike.



Offline CB750faces.com (Lecram)

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Re: 1970 CB750 project "Dad's bike"
« Reply #29 on: March 28, 2015, 03:10:47 AM »
Great project! It looks pretty original, but a load of work to do.



Offline calj737

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Re: 1970 CB750 project "Dad's bike"
« Reply #30 on: March 28, 2015, 03:58:31 AM »
Definitely remove your bearings and bushings prior to powder coating. You run the risk of grease and grime leeching out during the heating process and destroying the beautiful finish of the powder coat.

Ditto on the condition of that collar!
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'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"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: 1970 CB750 project "Dad's bike"
« Reply #31 on: March 28, 2015, 07:23:47 AM »
Definitely remove your bearings and bushings prior to powder coating.

+1.  Then clean it out real good and buy a piece of all thread, 2 large fender washers and nut and put it in the swing arm. This will prevent the PC from going in there, and you'll be able to install the new bushings with no issue.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #32 on: March 28, 2015, 09:05:00 PM »
Definitely remove your bearings and bushings prior to powder coating.

+1.  Then clean it out real good and buy a piece of all thread, 2 large fender washers and nut and put it in the swing arm. This will prevent the PC from going in there, and you'll be able to install the new bushings with no issue.

So I will need to replace the bushings when I remove them or can they be reused?

thanks so much everyone.

Offline calj737

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Re: 1970 CB750 project "Dad's bike"
« Reply #33 on: March 29, 2015, 04:26:25 AM »
It's advisable to replace them with new oil lite bronze bushings. Many members source them from a chap in Germany for around $20
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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: 1970 CB750 project "Dad's bike"
« Reply #34 on: March 29, 2015, 01:21:46 PM »
It's advisable to replace them with new oil lite bronze bushings. Many members source them from a chap in Germany for around $20

Cal knows his stuff, I'll make it easy for you, click here...

http://www.ebay.com/itm/Honda-CB-250-360-400-500-550-750-Four-swingarm-bronze-bushing-set-bearing-new-/251851928293?vxp=mtr&hash=item3aa38b72e5
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #35 on: March 29, 2015, 04:03:50 PM »
It's advisable to replace them with new oil lite bronze bushings. Many members source them from a chap in Germany for around $20

Cal knows his stuff, I'll make it easy for you, click here...

http://www.ebay.com/itm/Honda-CB-250-360-400-500-550-750-Four-swingarm-bronze-bushing-set-bearing-new-/251851928293?vxp=mtr&hash=item3aa38b72e5

The bushings I have don't have the lip on them.  They insert all the way into the swingarm tube.  These look like ones for a later bike.  Are they interchangeable so I can eliminate the end cap that sits under the cup washer?

Offline ECM

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Re: 1970 CB750 project "Dad's bike"
« Reply #36 on: April 07, 2015, 12:11:58 AM »
So have steadily been trying to get the pistons un-stuck for a few weeks now.  Lots of sitting with ATF/Acetone in the bores.  Now even resulted to a bit of fire to heat things up and still can't budge them.
 
Any other options I should consider?  I am not sure if disconnecting the connecting rods from the crank and taking the jugs with pistons to a machine shop is the next step.  Not sure if they would be able to help me other than maybe taking a press to the pistons.  I would like to save the connecting rods as I really don't want to mess with the mix and match of new connecting rods/crank/case to get everything balanced and bearing tolerances figured out like I have read about.
 
Can a machine shop do anything for me?  (I called one today, but they are off on Monday's, will have to follow up tomorrow)  Anything else I should consider to get these pistons unstuck?
 
An extra piece of info, I do have another set of pistons/jugs/head I got as a packaged deal as I knew I was going to need new pistons anyway.  Not sure if that helps in figuring out options as this might turn to a destructive process to get this engine rebuilt.

Offline calj737

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Re: 1970 CB750 project "Dad's bike"
« Reply #37 on: April 07, 2015, 03:38:28 AM »
"Resorted to a bit of fire..."  Pursue this approach. You'd be surprised at how long you may need to BBQ those pistons to get them free. Mine took 2 hours of tending the fire. Ignite, burn, refill, ignite, marshmallows, refill, etc...

When they ultimately did move, they didn't move far. I had to use a breaker bar on the crank bolt (the alternator side ONLY) and then only slipped them high enough to reach the bottom of the sleeves. I applied propane to the sleeves to get them the rest of the way loose.

You can use Kerosene, Diesel (smokes like a beetch) or SeaFoam. It won't hurt anything. Just do it all outdoors and be sure your motor is securely fastened to something so when you go to cranking on the alternator bolt, it doesn't topple.
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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 Davez134

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Re: 1970 CB750 project "Dad's bike"
« Reply #38 on: April 07, 2015, 05:35:25 AM »
It's advisable to replace them with new oil lite bronze bushings. Many members source them from a chap in Germany for around $20

Cal knows his stuff, I'll make it easy for you, click here...

http://www.ebay.com/itm/Honda-CB-250-360-400-500-550-750-Four-swingarm-bronze-bushing-set-bearing-new-/251851928293?vxp=mtr&hash=item3aa38b72e5

The bushings I have don't have the lip on them.  They insert all the way into the swingarm tube.  These look like ones for a later bike.  Are they interchangeable so I can eliminate the end cap that sits under the cup washer?
Yes, you can use these bushings on your swingarm. I used those exact ones on my '72 after removing the "old style" ones without the lip. Then all you need is cup washer.
http://forums.sohc4.net/index.php/topic,139768.msg1642346.html#msg1642346