swing arm bushes

Hi All, I have investigated the play in my swinging arm(not much play, but after reading about the engine plates wearing etc) the play is in the bushes which are fairly dry. No need to replace as wear is very slight. Question is, the bushes seem to be p/bronze, but I have no grease/oil nipples to top up, is it a good idea to fit these while I've got the arm out & should I find a better way of securing the s/arm pin in the plate?

As always thanks in advance, Paul.

hayabusaman0 said:

Question is, the bushes seem to be p/bronze,

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The bushes should be made of sintered bronze (Oilite).

hayabusaman0 said:

but I have no grease/oil nipples to top up,

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No oil nipple would suggest it's the "sealed for life" assembly with felt wicks and welch plugs?

hayabusaman0 said:

should I find a better way of securing the s/arm pin in the plate?

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Is the spindle still a good fit in the cradle?

L.A.B. said:

The bushes should be made of sintered bronze (Oilite).

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Not sure what they're made of .

L.A.B. said:

No oil nipple would suggest it's the "sealed for life" assembly with felt wicks and welch plugs?

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Yes

L.A.B. said:

Is the spindle still a good fit in the cradle?

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Yes

L.A.B. said:

The bushes should be made of sintered bronze (Oilite).

hayabusaman0 said:

Not sure what they're made of .

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If they are original parts then they will be sintered bronze or "Oilite" which is porous (why they need oil-not grease) so they are practically "self-lubricating" and do not require much lubricant (EP140).

Are you sure that the spindle, aka the pin, is a tight fit in the female tube that it resides in? This is the more common problem - a worn spindle tube.

Generally, swing arm bushings, be they bronze or oilite, do not wear. Typically, they pick up grit and hold it, and then the steel is cut by the grit embedded in the bushing, resulting in a greater need for a new spindle (pin) than for new bushings.

I was going to ask how tight should the pin be? I can push it in without any trouble & the pin is only worn by .0005". I can't feel any play when the pin is bolted in place & there are no wear marks on the pin where it sits in the cradle.

Cheers, Paul.

In my opinion, with the swing arm in the bike, if there is any detectable play, then it is too loose. It might be best for you to get your head and eyes up close while, with the shocks disconnected, someone else tries to create detectable play; then identify whether it is in either the swing arm bush/spindle junction, or in the spindle/spindle tube junction.

I would get a long bolt or stud that will screw into end of spindle, the rear isolastic bolt is ideal. Screw it into shaft & lock it securely with a lock nut. Then slide the shaft into the cradle without swinging arm fitted. The extra length will help detect any play. If there is no play, great. Do the same with shaft pushed through swinging arm only to check for play there. If there is play in the cradle you have two choices. First is to ream cradle oversize & use oversize shaft & reak bearings to match. Second is If there isn't much play you can use one of the DIY methods to secure the shaft in the cradle. If you search on this site you will find various ways to do it. Some more rough & ready than others. The most rough & ready that works is to use a U bolt type exhaust clamp around the tube in the cradle to literally squeeze the tube to hold the shaft. Crude but effective.

Years ago my cradle wore quite badly & as the bike was my only transport I kept riding it until I got chance to replace the cradle. I could feel the wheel move side ways at times but it was never dangerous & never caused me any traumas. It amused my friends when following me as they said they could see the wheel move sideways. People joke that Commandos have a hinge in the middle & mine literally did.

Ian

hayabusaman0 said:

I was going to ask how tight should the pin be? I can push it in without any trouble & the pin is only worn by .0005". I can't feel any play when the pin is bolted in place & there are no wear marks on the pin where it sits in the cradle.

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The thing is, you are really the only one in a position to decide if there is play or not (uness you seek a second opinion).

The bushes are cheap, so personally, I would probably renew them anyway.

hayabusaman0 said:

I was going to ask how tight should the pin be? I can push it in without any trouble & the pin is only worn by .0005". I can't feel any play when the pin is bolted in place & there are no wear marks on the pin where it sits in the cradle.

Cheers, Paul.

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It's usually not the pin or the swingarm that wears. It's the cradle!

As i said, the pin does not move when bolted into the cradle, when wiggled about the end of s/arm moves approx only 1/4" you can see movement between bush & pin, as there is only .0005" wear on the pin & there is minimal wear on the bushes I won't be replacing any of it. As the bike has only done 17000m(I believe, built by M.Hemmings)so I don't know if the bearings were lubed or not, it seems to me it would be better to either drill & fit a grease nipple to top up oil when serviced or do away with the felt wick & just use grease, looking at the pin it looks to me that it would be better having the holes that lube the bearings at 90 degrees to where they are now because that's where most of the wear is?

Thanks, Paul.

hayabusaman0 said:

I don't know if the bearings were lubed or not, it seems to me it would be better to either drill & fit a grease nipple to top up oil when serviced or do away with the felt wick & just use grease, looking at the pin it looks to me that it would be better having the holes that lube the bearings at 90 degrees to where they are now because that's where most of the wear is?

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An "Oilite" bush can absorb 15-20% of it's volume in oil, (or more according to the specific Oilite type) therefore it shouldn't matter where the oil actually comes into contact with the bush because the sintered structure will absorb it and distribute the oil throughout the bush.

http://www.nskamericas.com/cps/rde/xbcr ... Oilite.pdf

hyabusaman I sent you a pm.

Here's some time-lapse photography which shows how the Oilite bush readily absorbs oil.

I put one drop of cold SAE50 engine oil onto a swinging arm bush and then photographed it.



I then took further photos at 2 minute intervals.





After 12 minutes, the oil had been completely absorbed by the bush and there wasn't the slightest trace of oil left on its surface!

Wow, you really need a hobby :shock: Good stuff.

Just like the new Depends diaper! My swingarm - cradle -bush has two weld areas at the cradle helicoiled for 1/2 bolts to crush/secure the pin to the cradle tube. Plus the original centerbolt on the top. I use STP oil additive which flows like cold molasses in the pin reservoir cavity. The bushes do not wear. Grease is the enemy . Never clog up the tiny lube holes with grease.

So to start off, do I soak them in oil & let the pin(with wick) soak in oil all night or what?

Cheers, Paul.

hayabusaman0 said:

So to start off, do I soak them in oil & let the pin(with wick) soak in oil all night or what?

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Yes, give the bushes and felts a good soaking.

Once everything is re-installed, the oil saturated felts will top-up the bushes as they slowly begin to dry out.

Many thanks to you all.

Paul.

+ 1 on the Good to know category L.A.B. Thanks,Cj