Topic: CB750K 1978 - Swingarm & Bushings

[trigger]

The ID of the bush is 21.50 and they fit perfectly to the collar, Some pic's 

[rosewood]

If those bushes are this listing?:

https://www.ebay.co.uk/itm/Honda-CB-750-Four-k0-k1-k2-k6-Swing-Arm-Bearing-Bronze-Bushes-Set-Swingarm/273323100524?hash=item3fa353896c:g:ahsAAOSwd0ha~S5k

he states the ID is 21.6mm seems very odd that they would measure at 21.2 once installed unless your tube on your swingarm is way out of round from years of use. To measure these accurately you need a bore guage and mic in both x and y directions to determine roundness. That collar will definitely be worn and out of round aswell.

Best to replace that collar and ream/hone the bushings to fit.

[754]

How did you put them in.
If you drove them In with hammer and drift, they will often close up, just around the openings the whole bushing may not be tight.
Did you try the bushing over the shaft, before installing ?

[kixbox]

How did you put them in.
If you drove them In with hammer and drift, they will often close up, just around the openings the whole bushing may not be tight.
Did you try the bushing over the shaft, before installing ?

No, I took a more gentle approach and took my time.  I used a thick all three rod and some strong nuts/washers.  It was a very smooth insertion (took some force to turn the nuts, but all was good and straight).

My biggest mistake is I did not check the fit before starting assembly.  This is essentially where I went wrong - in the prep stage.  I made the assumption that it will be fine. 



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[kixbox]

The ID of the bush is 21.50 and they fit perfectly to the collar, Some pic's 

Thanks for sharing these pictures bud, good vote of confidence on the product. 

The supplier I bought these from was extremely kind morbid.  Refunded me and sending me a new set - couldn’t be more grateful for how he had handled the situation.  I simply called him for advice and took the extra step to make me happy. I was blown away. 

One I receive them, I’ll take accurate measurements again and share out results. 



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[70CB750]

It takes a fitter or toolmaker to make it work 

Here, joke about a fitter.

Manuel and Pedro worked together and both were laid off, so they went to the unemployment office. When asked his occupation, Manuel answered, "Panty Stitcher. I sew da elastic onto ladies' cotton panties."

The clerk looked up Panty Stitcher. Finding it classified as "unskilled labor," she gave him $300 a week unemployment pay.

Pedro was asked his occupation. "Diesel Fitter," he replied. Since diesel fitter was a skilled job, the clerk gave Pedro $600 a week.

When Manuel found out he was furious. He stormed back into the office to find out why his friend and coworker was collecting double his pay.

The clerk explained, "Panty stitchers are unskilled and diesel fitters are skilled labor"

"What skill?!" yelled Manuel. "I sew the elastic on da panties, Pedro puts dem over his head and says: 'Yeah, diesel fitter.'"

[kixbox]

Hahhahahhahahaha


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[kixbox]

Quick update:

Had the shaft/collar measured accurately and it turns out that one side is worn/deformed without any straight lines down any point on the circumference.  It looks like I am in for a new collar (on the hunt, super difficult to find). 

Going to pop the bushings out to start from scratch.  I’d rather go down that route given the importance of this.  This time, I will pre fit everything to make sure this will go in right.

Stay tuned for more.





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[seanbarney41]

Are you aware that Hondaman will service your swingarm by first trueing your collar on a lathe and then turning bushes to exactly fit the resulting size of your collar?  Last I checked, he does all that for small money as well....

[kixbox]

Are you aware that Hondaman will service your swingarm by first trueing your collar on a lathe and then turning bushes to exactly fit the resulting size of your collar?  Last I checked, he does all that for small money as well....

Yes, I am.  Him and I are having a side PM exchange on things to do before I resort to that option. I am weighing the cost of doing it home vs shipping to him (from Canada - not cheap these days). 



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[SKTP]

When I had Hondaman do my 1978k swingarm rebuild I found an older (1974) shaft that had grease grooves in it which I have been told is superior to the later swingarm shafts

Here's the comparison picture:

http://forums.sohc4.net/index.php/topic,68423.msg860342.html#msg860342

[rosewood]

I went through this same exercise and couldn't find a replacement collar which looks the same as your particular one. They all differed in the outer diameters over the years...I purchased a new model collar with the helical grease grooves and a bolt with zerk fittings at each end.

The bronze bushings I purchased from germany via ebay were a little too loose for my liking with the new collar which was slightly undersized compared to my original so I resorted to finding some bronze and machining my own on CNC lathe (I'm fortunate to have access to the equipment at work) If I was in the US I would have sent to Hondaman it would have saved alot of time and money.

The end result though is perfect though no play in the swingarm at all... 

[kixbox]

I went through this same exercise and couldn't find a replacement collar which looks the same as your particular one. They all differed in the outer diameters over the years...I purchased a new model collar with the helical grease grooves and a bolt with zerk fittings at each end.

The bronze bushings I purchased from germany via ebay were a little too loose for my liking with the new collar which was slightly undersized compared to my original so I resorted to finding some bronze and machining my own on CNC lathe (I'm fortunate to have access to the equipment at work) If I was in the US I would have sent to Hondaman it would have saved alot of time and money.

The end result though is perfect though no play in the swingarm at all...

Thanks for sharing and making feel better bud!

I’m a bit jealous cause that is full custom

I’m going to take out the bronze bushing again and start all over (which I guess you know what that is like).  Have no idea how I’m going to get them out but going to go caveman on them (I think).



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[rosewood]

check your pm's....mine tapped out easily, but they pressed in very easy aswell..

[754]

Polish your shaft, spend 30 bux or so an an adjustable Reamer ..
 You will be done  a few hours after the reamer arrives.
 Meanwhile  we figure out a way to polish your sleeve on a dril, press or lathe.,

[kixbox]

Hi all - here is a big update as promised:

- got the bronze bushing i installed in July out (gently and safely), without damage to the swingarm. 

- cleaned the inside thoroughly.

- measured swingarm ID carefully and things looked good.  Circular and nothing out of shape. 

- this point is big: contacted Honda directly, they searched their database of dealers across North America (was impressed they even took my call).  They found ONE dealer in New Orleans that had a BRAND new swingarm collar (which has been out of production for some time now).; turns out it was the only and last one for sale that was available in NA.  Contacted the dealer directly and they were able to find it in their storage (took them a few hours).  They were very open to have it shipped to me up here in Canada.  I could not be more lucky and grateful for their service.

- got new bronze bushings from Germany (exact same ones pictures earlier in the thread). 

- IMPORTANT: measures fittings IDs/ODs before I began the assembly.

- assembly was straightforward: pressed bushings super super carefully, Colorado was slid in.  Fitment was perfect! Bushings and collar were in freezer for three days before assembly. 

Life lessons:
1) patience and careful prep pays off
2) where there is a will, there is a way
3) don’t ever underestimate the kindness of people (this is huge).

I am so grateful for this forum members: your input and advice where very helpful. I could have done it without this thread and the other threads online. 

I did not take any pictures - in the excitement of the process and having things work - it slipped my mind to document. 

But here is the engine implanted for your viewing pleasure.  I’ll take more pics of swingarm installed. 











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[Erny]

Nice pics! Looks like very nice garage, have to be pleasure to work there! 

[70CB750]

Looking good