Author Topic: Question for Hondaman - Swingarm collar (Read 5838 times)

timmytim · « **on:** January 25, 2015, 01:32:53 PM »

Afternoon Everyone! First off let me say what an awesome resource this forum is. I have been using this site during the restoration of my '75 CB550 and also my most recent addition a '76 CB750. Thank you all who post their how to's and tricks to fix some of the issues with our bikes. Now for my question.

Hondaman I know you are a resident expert on the swingarm on these bikes so I was hoping you could lend me some advice. below are some pics of my current collar out of the '76 750K I am currently rebuilding. I have the new bronze bushings installed in the swingarm already and was attempting to re-install the collar when it would not go in on one end easily into the new bushings. What are your thoughts on this collar? is it toast or what? the bad side will fit into the bushings and spin freely without too much play. The other side will not spin in the bushing freely. Is it normal to be that tight of a fit? I do remember I had to pound it out of the swing arm when I took it apart. Nasty grease in there i'm sure that was original with the bike.

Here are the specifics:
1976 CB750 K
~45,000 mi
bronze bushing ID .847"
collar OD .844"

MiGhost · « **Reply #1 on:** January 26, 2015, 10:55:14 PM »

Quote from: timmytim on January 25, 2015, 01:32:53 PM

I do remember I had to pound it out of the swing arm when I took it apart. Nasty grease in there i'm sure that was original with the bike.

From that pic it looks like you may have mushroomed the end when you pounded it out. That collar deffinately looks like it has seen better days.

NobleHops · « **Reply #2 on:** January 27, 2015, 07:17:44 AM »

Quote from: timmytim on January 25, 2015, 01:32:53 PM

Afternoon Everyone! First off let me say what an awesome resource this forum is. I have been using this site during the restoration of my '75 CB550 and also my most recent addition a '76 CB750. Thank you all who post their how to's and tricks to fix some of the issues with our bikes. Now for my question.

Hondaman I know you are a resident expert on the swingarm on these bikes so I was hoping you could lend me some advice. below are some pics of my current collar out of the '76 750K I am currently rebuilding. I have the new bronze bushings installed in the swingarm already and was attempting to re-install the collar when it would not go in on one end easily into the new bushings. What are your thoughts on this collar? is it toast or what? the bad side will fit into the bushings and spin freely without too much play. The other side will not spin in the bushing freely. Is it normal to be that tight of a fit? I do remember I had to pound it out of the swing arm when I took it apart. Nasty grease in there i'm sure that was original with the bike.

Here are the specifics:
1976 CB750 K
~45,000 mi
bronze bushing ID .847"
collar OD .844"

As suggested, why don't you put a micrometer on a few different spots on the collar and report back. If you have a flat block of some kind too, lay it down and roll it for a quick check for runout. If it's not too far off, you may get away with skimming it true on a lathe to knock off any high spots or mushrooming, but if it's far out you might be better served just sourcing a good one.

N.

Bodi · « **Reply #3 on:** January 27, 2015, 09:09:05 AM »

If one collar end fits well in both bushings but the other end is tight you probably mushroomed the end you hammered on.
Mushrooming can be removed with a flat file - mill smooth or smooth. Dead smooth is probably too fine but if that's all you have... try it. You will be able to feel the high spots on the end, just file until they are gone - you don't want to make the overall collar diameter much smaller. Roll the file around the collar as you stroke so it doesn't make a flat spot.

timmytim · « **Reply #4 on:** January 29, 2015, 11:54:55 AM »

Thanks for all of the suggestions guys. When I measured it the first time I took several measurements on both ends, rolled it on a flat surface and didn't come up with anything noticeable. I'll go back and try a few things again and see what I come up with. Does anyone have a good used one from the earlier bikes out there? Would like to have one with the grease grove in it if I'm going to replace it.

timmytim · « **Reply #5 on:** February 07, 2015, 09:37:04 PM »

Update: old collar was mushroomedon one end so decided to replace.
Bought a new collar from dss and a used bolt w/two zerk fittings at the end (retaped to us zerk fitting). New bronze bushings installed (ebay from performanceintl) and the whole swingarm seems tight in the frame. I can move it up and down but it takes a good bit of pressure to get it up and down. Torqued to 42 and to 35 with no difference. Loosen it up a bunch and then moves freely.

Am i missig something or should it be this tight?

mystic_1 · « **Reply #6 on:** February 08, 2015, 06:39:28 AM »

You said you installed new swingarm bushings. Were these the flanged bushings like this?

If so, you may not have seated them fully, allowing them to rub against the swingarm pivot caps (#10 below).

Ordinarily, the length of the swingarm pivot collar (#9) is slightly longer than the width between the end faces of the swingarm bushings. Thus, when you bolt the unit into the frame, all the pinch force is applied to the caps and the collar, not to the bushings and the swingarm.

Measure the length of your pivot collar and compare to the width of the swingarm with the bushings installed. If the swingarm is wider, either the bushings aren't fully seated or the flanges on them are too wide and you could shave them down a bit to achieve proper clearance.

mystic_1

mystic_1 · « **Reply #7 on:** February 08, 2015, 06:41:36 AM »

Oh, and no it shouldn't be all that hard to pivot the swingarm. It shouldn't have any play of course, but if it's not hooked up to the shocks it should be free enough to swing from it's own weight when you let it go.

mystic_1

timmytim · « **Reply #8 on:** February 08, 2015, 07:06:10 AM »

Thanks for the quick response! I removed all powdercoat prior to installing the flanged bushings, did the freezer trick and they went in quite easily with little taps with a rubber mallet. Looking at them the look to be fully seated with no more room to move.

Honestly looking at the setup the collar doesnt seem to stick out past the swingarm at all when installed.

Has anyone installed the bearings from performanceintl before and had an issue? New collar and new bushings should = no modification necessary right? Frustrating....

timmytim · « **Reply #9 on:** February 08, 2015, 07:08:22 AM »

Also, i measured the old bearing flange with a caliper and it matches the new bronze ones....

mystic_1 · « **Reply #10 on:** February 08, 2015, 07:28:26 AM »

Quote from: timmytim on February 08, 2015, 07:06:10 AM

Honestly looking at the setup the collar doesnt seem to stick out past the swingarm at all when installed.

Have you compared the length of the new pivot collar to the length of the old one? Keep in mind that the mushroomed one is now slightly shorter than it was before due to the distortion.

I would put the collar into the swingarm and then rest one end on a flat surface, then place a straight edge across the other end. See where it's touching. If the straight edge is resting on the bushing flanges, and not the end of the pivot collar, that's definitely the source of your binding. The length difference here is very small, like feeler gauge small, but very important.

mystic_1

timmytim · « **Reply #11 on:** February 08, 2015, 04:27:46 PM »

So I spend most of the day trying to figure out this swingarm deal. After a few measurements I determined for some reason the collar was not protruding as needed out of the swingarm. So in the vice and out with the file. I was careful to be uniform with the file and kept it as level as possible while working it back and forth. Fianlly got it where it needed to be. installed the thing back in and boom....perfect at the recommended torque. Not sure what the overall problem was, didn't quite get all of the powdercoat off or if the bushing top hat's were just a touch too large, but now it is in and moves with just a little force up and down.

Again, thanks to all who helped out with the trouble shoot. i'll try and post some pics of a mock up of what she looks like in a bit.

NobleHops · « **Reply #12 on:** February 09, 2015, 09:26:41 PM »

Nice job Timmy. Sometimes you have to 'make it work', and you did.

HondaMan · « **Reply #13 on:** February 09, 2015, 10:42:19 PM »

Sorry to be late to the party! For some reason, I never saw this post until today.

The collar must be .002" to .004" longer than the stacked-up total of the end caps (or flanges, in the case of flanged bushings). This compresses to 0.00" at about 25 ft-lbs of bolt torque on the swingarm bolt.

The clearance in the bushing-to-collar interface is .0008" to .0016" new. Honda declares them worn out at 0.0032" clearance on either side. If both sides are worn this much, the rear wheel will move 1/4" (.250") side-to-side at the axle on the 750, a little less on the smaller bikes (shorter swingarms).

Sometimes this side-to-side movement can become masked if the collar does not stick out far enough, or if the bolt is over-tightened to compress the collar more, because the frame tends to hold the arm still when trying the side-to-side side at the rear axle. (or, if the pivot was just greased and it hasn't spread out yet.) So, when I test the final fit-ups, I loosen the bolt until the axle can move, then start tightening it until it either reaches 18-25 ft-lbs, or stops moving. This is my "perfect fit" test for these bikes.

It's all about riding safe, IMHO, so this is one spot on these bikes that I don't compromise. Those who have had me rebuild their arms understand why.

timmytim · « **Reply #14 on:** February 10, 2015, 11:20:01 AM »

"So, when I test the final fit-ups, I loosen the bolt until the axle can move, then start tightening it until it either reaches 18-25 ft-lbs, or stops moving. This is my "perfect fit" test for these bikes.

"

Are you saying that you can be OK with a torque of 18-25 ft-lbs on the swingarm bolt? I believe the Cylmer was something like 35-42 and another resource salocal.com shows 32-50. I know this is your area of expertise so I will go with your recommendation. I do know that when it was a bit less upon assembly that the 20ish mark was a noticeable difference in movement than at the current setting I have it at ~34 ft-lb. Thanks again!

timmytim · « **Reply #15 on:** February 10, 2015, 11:33:39 AM »

Promised pics of the build so far. Was all the way down to the frame and now is on its away back to a roller.
Day i brought her home

This weekends mockup with new seat and old tank.

HondaMan · « **Reply #16 on:** February 10, 2015, 01:47:52 PM »

Quote from: timmytim on February 10, 2015, 11:20:01 AM

"So, when I test the final fit-ups, I loosen the bolt until the axle can move, then start tightening it until it either reaches 18-25 ft-lbs, or stops moving. This is my "perfect fit" test for these bikes. "

Are you saying that you can be OK with a torque of 18-25 ft-lbs on the swingarm bolt? I believe the Cylmer was something like 35-42 and another resource salocal.com shows 32-50. I know this is your area of expertise so I will go with your recommendation. I do know that when it was a bit less upon assembly that the 20ish mark was a noticeable difference in movement than at the current setting I have it at ~34 ft-lb. Thanks again!

This 18-25 ft-lb figure is just for test purposes, not for final assembly. If it snugs up at 18, it's usually perfect, if it takes 25 then it's still acceptable (to me) as you will go tighter in the end. The early bolts (with the grease zerks) have a lot of sharp milled edges on them (and are a little bit smaller diameter), so they won't take as much [over]torque as the later ones without stretching somewhat. The 'trouble' with applying the full torque and then checking for axle movement is: the frame usually clamps it so tight then that you can't find any movement, unless the collar's clearance is a disaster!

Godffery · « **Reply #17 on:** November 23, 2015, 11:10:42 AM »

Dude, Nice collection of bikes you have there!
You totally need to hook up with the the Chi'Vin'Moto group. http://chivinmoto.com/wordpress/

G~

alacrity · « **Reply #18 on:** November 23, 2015, 11:26:16 AM »

Also I have found that it works best if you loosen ALL The motor mount bolts and studs... then do the swingarm the way Hondaman describes, then go back and re-tighten all motormount bolts and nuts to proper indicated torque (Honda service manual). If you look at it all as a system, see the space around all the bolts in the bolt holes/passages? That's "slop" -- it's not self-centering. IF you do the swingarm last, you can find that you are tightening it into a frame where the holes aren't aligned/centered as well as they could be. Let the frame relax... DO the swingarm and check for fit and functionality, and then go do the rest of the frame bolts in an incremental even fashion (sorta emulate the way you'd torque the head nuts). It should find a happy center space for everything... And of course now go back and check your swingarm, which should feel precisely the way it did before you went after the rest of the frame bolts. Guess what it means if the swingarm is now locked up and doesn't move?

HondaMan · « **Reply #19 on:** November 23, 2015, 05:58:40 PM »

Quote from: timmytim on January 25, 2015, 01:32:53 PM

Here are the specifics:
1976 CB750 K
~45,000 mi
bronze bushing ID .847"
collar OD .844"

Well, umm...having a clearance of .003" between the collar and bushing is the "worn out" point for the pair.

Here's why: you must add the clearances of BOTH sides' bearings, then multiply by the length to the rear axle, to get the side-to-side play the swingarm will see at the rear tire. In this case, that is:

(0.003" + 0.003") * 18" = 0.108" (not quite 1/8")

That much 'slop' will cause the bike to do things like: when coming up from a corner, the bike will feel like it slid sideways toward the outward side of the turn, each time you turn. If you are in a right turn and add throttle, it won't affect much: if you are in a left turn and apply throttle, it will try to stand the bike back up a little by shortening the turn radius. In a striaght line, it makes the bike feel like it has a mind of its own, not holding a solid line.

Many people over the years have 'blamed' this (in the Hondas, Suzys, and others of the era) on "poor frame design", but in my experience it has always been the combination of solid bushing clearances and tapered steering head bearings that made the bike handle, or not. (After that, there's other things like suspension, but that's another topic.)

If you measure that worn end of the collar, you will find it egg-shaped or oval-shaped. They typically wear on the front or back of the collar, based on how it was located in the frame. Use a mic if possible, as calipers have too much "wiggle" to get a good measure on round stuff like these. A small bore gage will get that ID, too.

Here's the 'real' specs the arm should see:
Most 550 arms need 1.0435"-1.0438" OD, 0.8444"-0.8446" ID (bronze bushings).
The collar, new, is 0.8440"-0.8442" (from Honda). This means that a freshly-assembled arm should have less than 0.0012" worst-case clearance (both sides added) for solid performance.

I suspect the best you can hope for is a new collar?

I just ran out of the last batch I had made in January, have to find someone to make some more for me. Honda quit them (again) a couple of years ago, but maybe Yamiya still has one? The 750K/550K collar is identical and the 750F/550F collar likewise. The 2 are somewhat different in sizes (OD), though.

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Author Topic: Question for Hondaman - Swingarm collar (Read 5838 times)