Swingarm Bushings

If it's broken or just needs tweaked

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Chris
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Swingarm Bushings

Postby Chris » Fri May 05, 2006 11:40 pm

As I mentioned in a different topic, the swingarm on my 1980 CB650c had a ton(about 3/32 - 1/8in.) of lateral movement. After checking the torque on the pivot bolt, I removed the swingarm today to check the bushings. I don't really see any wear on the outside edge of the bushings or on the dust covers. When I tried to check the O.D. of the collar and the I.D. of the bushing, the dimensions were way bigger than stated in the Honda CB650 Shop Manual. So now I'm wondering if maybe someone installed the wrong bushings and collar all together. I took some pictures in hopes that one of you might recognize if these are the proper parts for my bike...
Image
Image
any of this look familiar? There's not alot of play between the bushings and the collar, so maybe I could just insert some steel shims between them and the dust covers to take up the slop?
1980 CB650c

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Vatch
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Postby Vatch » Sat May 06, 2006 7:38 am

I am less knowledgable than others on here, but I don't think you want to put shims in there. If both ID and OD are large it sounds like a bad replacement part. How is the fit of the pivot bolt in the swing arm? Is there play there?
'99 1500 Drifter

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Chris
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Postby Chris » Sat May 06, 2006 9:14 am

No play in the pivot bolt. I had to drive it out with a soft hammer. I finally realized this morning where it is that I've seen shims that size. Valve spring shims from a small block chevy engine should fit perfectly. Do you really think it would matter if I put a couple between the shoulder of the bushing and the dust cover? I've been told that this is a common adjustment on some dirtbikes. I'd like to do a proper job, but I'd also like to hold onto my cash if I can. If shims would get me through the summer, I'd be more than satisfied. As far as it being a poor replacement part, I think you may be right. The drawing in the shop manual shows some sort of grooves in the sleeve under the bushings and as you can see in my picture there are no grooves on mine.
1980 CB650c

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Vatch
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Postby Vatch » Sat May 06, 2006 10:05 am

Chris wrote: Do you really think it would matter if I put a couple between the shoulder of the bushing and the dust cover? I've been told that this is a common adjustment on some dirtbikes.


Sorry, I can't say with any certainty. Perhaps some of the others on here could tell you.
'99 1500 Drifter

Robert
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Postby Robert » Sun May 07, 2006 12:50 pm

Hi,

the dimensions in the (1979) CB650 shop manual are valid for the cb 650 only.

The correct dimensions for the CB650C (1980) are:

Swing arm pivot bushing I.D.
Standard: 23.519 - 23.552 mm
(0.9260 - 0.9272 IN)
Service Limit: 23.7 mm (0.93 IN)


Sing arm center collar O.D.
Standard: 23.427 - 23.460 mm
(0.9223 - 0.9236 IN)
Service Limit: 23. 4 mm (0.92 IN)

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Volker_P
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Re: Swingarm Bushings

Postby Volker_P » Mon May 08, 2006 12:56 am

I am not sure what you want to do. If the frame gap for the swingarm is too large for the swingarm with bushings and covers, the frame is pulled together with the axis screw (as long as the thread is intact at required length). That's it, no need for shims and washers. So where do you want to put in shims? Anyway, if the play of the bushings on the collar is too large (how much difference do you have to Roberts values?), no tricks will help.

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Chris
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Postby Chris » Mon May 08, 2006 12:41 pm

Yeah, it's a funny thing. I cleaned up and painted the swingarm yesterday. I cleaned the threads on the pivot bolt because they had corrosion on them(from battery acid i think). I got up this morning and put it all back together with no shims and it's as tight as it could be. I must've been getting a bad torque reading because of the corrosion on the threads. Better make a note of that in case it happens to anyone else. Thanks for your help guys. :D
1980 CB650c

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Volker_P
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Re: Swingarm Bushings

Postby Volker_P » Tue May 09, 2006 12:47 am

Good to hear it worked. I bet you can feel an amazing difference. Press in some grease from time to time. :wink:

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Vatch
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Postby Vatch » Tue May 09, 2006 4:30 pm

That great news. If only all "problems" worked out so well. :?
'99 1500 Drifter

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1980cb650
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Postby 1980cb650 » Mon Jun 12, 2006 4:01 pm

What made you think you had a problem with your swingarm? Sometimes when I'm leaned over in a turn, it feels like the rear end is getting wiggly. I checked rear axle, it's tight, the shocks are tight. The swingarm bolt doesn't seem loose, but I don't really know what to do when it comes to that. What would cause a wiggling feeling in the rear when leaned over in a turn? The tire is new.

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Chris
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Postby Chris » Mon Jun 12, 2006 7:29 pm

I had the bike on the center stand and grabbed hold of the rear wheel and tried to wiggle it to make sure the axle was tight. The axle was tight, but the whole swingarm moved back and forth laterally at the pivot bolt. I immediately assumed that the bushings were bad. I spoke with a mechanic at one of the local Honda shops while pricing new bushings and he said to make sure I checked the torque on the pivot bolt before I replaced the bushings because he'd seen them loosen before. After seeing the price of a new set of bushings, I really hoped that it was just a loose bolt. But when I checked the torque it was right on. This was all before I ever took the bike down the road. When I finally rode it at speed, it was terrifying. At around 40-50 mph and with the suspension unloaded(like when cresting a hill) the ass-end would wiggle back and forth real bad. I don't remember if it did it in the corners or not, but I knew right away that it needed to be fixed before I rode it any more. In the words of my father(a seasoned biker), "That's the kind of shit that will put you down!" I didn't need him to tell me that, but I think he said it best. If you read the whole thread, I guess you know the rest of the story... dirty threads=false torque reading. It's a good idea to check your whole bike OFTEN for anything that might be loose including axles, fork bearings, swingarm, calipers, shock mounts, chain... anything and everything. Good luck and ride safe.
1980 CB650c

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nickjtc
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Wiggles

Postby nickjtc » Sat Jul 22, 2006 10:28 am

To me the 650 handles way better than the bikes of the early '70s, so if you notice something amiss it is almost certainly the bike telling you that something is not quite right, somewhere.

Remember to check ALL of the variables, though, not just the swing arm, especially if the old gal has a few miles under the wheels:

Tyre pressures/wear
Wheel alignment
Condition of the wheel bearings, front and rear
Condition/adjustment of the steering head bearings
Rear shock performance

...and anything else I've forgotten.
.....to be myself, a pattern for others.

1979 CB650
1971 Norton Commando
1968 CB175


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