Topic: How do you tell if Swing Arm is Loose ?

[rddcw]

Been working on my 74' CB 750 K4 for a little bit. Mostly trying to clean it up. Polished up Engine side cover and Fork tubes, cam out pretty nice. Installed New tires F/R. While the rear tire and wheel is off, it seems like to me that the swing arm has a little to much side play? Couldn't tell you how much but probably a few thousands. You can see the swing arm move slightly behind the dust caps when you rock the swing arm side to side with your hand.

Should I see if tightening the swing arm lock nuts on the outside of the frame would help? What would Guys suggest?

I've riden the bike a little. Didn't seem like a problem but didn't ride it too much distance. The bike has about 16,000 miles on it.

[BPellerine]

the bushings in the swingarm are starting to wear causing play,I would not tighten the nuts on through bolt unless real loose,if it still handles ok you might be good for awhile.bill

[mrbreeze]

Grab the rear wheel at the 12-6 position and again at the 9-3. Do this on the centerstand (or wheel off the ground). You gotta put some grunt into it while shaking it. You shouldn't feel any play. If you feel play use your eyes to see if its the wheel that's loose or the swing arm. Over tightening the swing arm bolt or the rear axle will only accelerate the wear that is already there. Could also be spokes but less likely. You might not feel anything out of the ordinary buzzing around town but if there's a problem you will more than likely feel it at speed.....especially if you get on a highway with grooved pavement.

[Henning]

Did you not ask about replacing swingarm bushings in another thread, or am I mixing you up with somebody else?

Anyway, tightening the swingarm bolt won't change anything, but it's always good to check that it's tight. It's easy to check for wear with the bike on the center stand. Simply push and pull the rear wheel sideways and you will feel the slop if there is any. I believe Honda's service limit is several millimeters, measured at the rear axle, translated to between 1/8 to 1/4 inch in your language. You won't be in doubt if you're anywhere near there. Old grease and crud can mask the true situation.

[rddcw]

I did Henning, but before I purchased New bushings I wanted to check with you Experts to determine if they were loose and how to go about checking it. I do Appreciate all of your Help as always and will order a set of Bronze bushings soon. Also,  Thank you Again for all your Tips in removing them !

[mrbreeze]

You may want to check with Hondaman about doing that swing arm. I did my own long ago before I heard about him but heard he's the man to do that particular job.

[seanbarney41]

You may want to check with Hondaman about doing that swing arm. I did my own long ago before I heard about him but heard he's the man to do that particular job.

+1...bushings won't help if your collar is knackered too(if the bike has much mileage, it most likely is), Hondaman machines bushings to match od of collar(or something good like that)

[mystic_1]

Got a set of calipers?  Throw the bike up on the centerstand, remove the swingarm, clean off ancient petrified grease, and MEASURE the collar and bolt.  This won't take more than an afternoon, and then you'll know for sure where you're at.

Even if you don't replace the bushings, cleaning pivot and re-greasing, then reassembling with proper torque, is totally not a waste of time.

mystic_1

[70CB750]

If you can make the wheel move from side to side by hand on center stand, you can be sure it is much worse on the road.

At minimum take it apart, measure, check and lubricate, but you should really look into replacing bushings.

[beemerbum]

What are the stock Honda swingarm bushings made of? I hope its not the plastic that Yamaha used on all their bikes.

[70CB750]

It changed over the years, Hondaman knows, I don't remember it.  Phenolic bushings were used for latest model Super Sports and likely Ks too.

[mrbreeze]

When I did mine I remember the OEM parts were around $200. It was about 10 years ago so I don't remember the details much. That 200 may have included getting the old bushings out. Should have done that myself.

[mystic_1]

Earliest bushings were brass IIRC, mid-year ones are some sort of sintered steel, very later ones phenolic (or so I hear, I've never seen them myself).

Older bushings had no lip, there was a separate felt sealing ring and a phenolic thrust washer on each end behind the pivot caps.  Mid-year models use the "top hat" style where the thrust washer is build into the bushing.

You may be able to tighten up the swingarm pivot a bit by just replacing the pivot collar tube, if yours is worn or rusted.  This assumes your bushings aren't completely shot (egg shaped, gouged, etc).

mystic_1