Topic: Swingarm bushing compatibility?

[geoluv]

It seems like there are 3 different parts available for swingarm bushings.  pre 74 everything used the bushings with the separate washers at the end.  Then they switched to the one-piece bushings with the lip.  Then the brass replacements became available which cost about $40.  And then there is the needle bearing upgrade which is around $120. 

Which makes the bike the stiffest?  And most importantly; are they all cross compatible?  I have seen conflicting info on whether the pre-74 swingarm can use the new brass one piece bushings.  They make a brass bush kit for the pre-74 bikes specifically but a good amount of the sellers of the one piece brass bushes say they are drop in replacements for pre-74 bikes.  Is the needle bearing upgrade worth it?  Does it work on pre-74 CBs?

Also I park my bike outside and ride in the rain sometimes, for those reasons I should just use the brass bushings  instead of the needle bearings?  Are the needle bearings really that much better than the brass bushings?   I don't want to be pulling out the shaft and checking the bearings all the time. 

[ekpent]

 I assume this is directed to the 550 guys ?

[540nova]

I don't think you'll notice any improvement with needle bearings. Either the swingarm moves freely, or it doesn't. The brass bushing is the way to go, for durability and close tolerance.


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[geoluv]

It is directed at the 550 guys but I was under the impression that the cb500, cb550, and cb750 for all years all use the same swing arm bushings/spacing.  Or at least that is what I am trying to figure out. 

[PeWe]

I installed the needle bearing kit in my CB750 K6 since the original stuff was shot. Plastic bushings.
The bearing got grease when installed and worked very well during the entire 80's. It got better shocks too, Marzocchi AG Strada.
4 long distance torungs where it had to work fine, each holiday riding 2500 km south, then 2500 km back home again. 2 persons with plenty of luggage. Speed around 100mph most of the time.

It looked good when I took it apart 2010, still grease everywhere despite no refill and about 60.000km.

I gave the bike another swing during the restore 2013. It was a K2 swing that was restored, powder coated and new needle bearing kit. Bike work fine with it and new shocks, IKON.
I'll use needle bearing kit for my ongoing build too a K2.  Do not forget good shocks.

The bronze bushings have got good reviews on this forum.

I am currently checking my latest project,CB750 K2. Swing bolt has a play in the frame when I just stick it in the frame holes. That is the older bolt with grease holes. I'll test the later massive. Play here must not be good.

[Darren Jakal]

Check out this thread and read what Hondaman has to say (towards end of page 1)

Greasing the swing arm on a 76 K model

http://forums.sohc4.net/index.php/topic,46432.0.html

dj

[rosewood]

Hi geoluv,

I'm personally going through the same exercise (rebuilding a 550F swing arm) I was a bit confused because I couldn't find the information I wanted (I never came across the the post Darren J has linked though which is very informative). So I contacted Hman directly and he kindly gave me the history of the changes over the years.

What probably hasn't been mentioned is the tolerances of the parts in terms of diameters as this results to the final play at the end of the swing arm and is very critical, even with factory spec parts this tolerance stack up can still lead to play which is close to the service limit set by Honda unfortunately. This is why Hondaman makes his own custom bushes for each swing arm he rebuilds so he can get the tolerances at the tighter end of the scale for the best possible outcome.

So it comes down to what specific parts you are using (pre and post 74) and if they are used how much have they worn. The collars pre and post 74 have   very slight differences in the diameter on the outer bearing surface which can make a difference to the end result. If you search you will be able to find this info on this forum from Hondaman.

If possible I would use a micrometer to measure your parts in term of external diameters on the collar and internal on the bush (especially if you are using an aftermarket bronze bush and a used collar...note the internal bush diameter can change once installed in the swing arm dependent on the interference. so they should be checked once installed in the arm also.

Have a read through this...if you search you will find other info aswell...

http://forums.sohc4.net/index.php?topic=144510.0


He has also mentioned to me the flanged/top hat bronze bushes have a tendency to break after 2-3 thousand miles, the top hat/flanged part cracks/breaks. something I hadn't read before..

For these reasons I have opted to go with a pre 74 setup in terms of collar and bolt. I am also going to use bronze bushings which I have already purchased and machine off the top hat/flange on them so they can be used with the felt seal and plastic end bushes. I will be mic'ing everything as I go to be confident I will get a good result. If I was in the US though I would probably be sending it to Hondaman after all the information I have come across on this topic.

hope this helps..
rosewood
 




 

[PeWe]

The shaft play in frame, then?
Bolt, Pivot or what else its called.

I'll try another bolt to see if it will sit tighter. I'll try with thin brass shim sheet around the bolt in frame as last resort. I did not think about this before when assemble my K6. I guess I just trusted the parts and put it together. Bike has no sign of soft, flexing rear though.

My experience is CB750, other bikes must be actual too