Swing Arm Bushes and Shaft

[nzpeterb]

After buying my Greeves TES a couple of years ago I've finally started work on it with the aim of entering it in an event in June next year. Hopefully I've left enough time as I can only work on it at weekends due to work commitments during the week.

One of the tasks to tackle was cutting the swingarm shaft as it's seized in the frame. The job was straight forward enough so far, but I've still got the outer sleeve of the bushes and the piece of shaft to remove from the centre of the frame. My questions are how to avoid a repeat seizure?

1. Why are the rubber bushes used? Could nylon bushes be machined up? That is all Honda used in their bikes in the 80's. There would be no chance of them seizing in future.

2. Would making the shaft out of stainless reduce its risk of seizing in the frame? I see modern trials bike use aluminium which also would not seize, but the modern bikes weight half what the Greeves does.

3. Alternatively has anyone tried machining a series of grooves around and along the shaft and adding a grease nipple to try and prevent seizing?

4. Has anyone tried anything else?

I'm interested in all constructive views.

Best Regards,

Peter Barnett
New Zealand.

[Phil Hyde]

Swinging arm technology........

Hi Peter

Unless you are seeking factory originality I would go with stainless steel for the SA spindle and nylon for the bushes. The original thread on the spindle was 5/8" UNF. if you can't get that thread and nyloc nuts, try an M16 thread.

The choice of metalastic bushes was Greeves following industry practice, Land Rover, Ford, etc. The established motorcycle factories BSA, Triumph, Norton, were stuck in the past.

Good luck

Phil

[John Wakefield]

I fully agree with Phil. A stainless steel shaft is the answer, certainly dont go down the grease nipple route, whilst a thin film of grease, maybe cooper slip, as used on car brake shoes on the shaft will be ok you dont want the grease coming into contact with the rubber in the bushes.
The good point of the metalstatic bushes is that they do not wear & particularly under the harsh conditions endured by trials & scrambles bikes. The fact that many of these bushes have remained serviceable for over 50 years says it all.
The only downside as you have experienced is that with the normal steel shaft rust sets in over a period of time between the steel bush inner & the shaft. A problem still current on more modern Jap bikes.

[nzpeterb]

Thanks

Thanks John and Phil,

Sounds like stainless steel is the best solution and I will still look at nylon bushes.
Got the shaft out of the frame today so just the outer steel sleeve from the original bushes left in the swing arm.
Got home tonight and my son had cut the old tyre off the rear wheel. It was so hard it was never going to come off the rim.
The back wheel with clean up OK but the front needs a new rim and spokes. This is because it has been changed to 19 inch and has hit too many Californian desert rocks.

By the way the bike has the full width alloy hubs and old heavy tyres.
Weighed them on the bathroom scales and both wheels with brakes, sprocket, and axles total just under 30 kg.
No wonder people change to non standard wheels.

regards,

Peter

[John Wakefield]

I will still look at nylon bushes.

If you are going to ride the bike particularly in trials forget about nylon bushes, they will wear rapidly. I remember a Sprite trials bike I had with nylon s/arm bushes & I was forever replacing them. Just refit new Metalastics with stainless steel shaft.

[Phil Hyde]

SA talk

A few more points. For my TFS Triumph Greeves I used precision ground stainless bar. Research a suitable nylon, Delrin comes to mind. Unless you are going to ride in deep sand and water nylon should be OK. A good silicone grease will help to keep the bushes clean. Also refrain from too much jet washing, or water blasters as they call them in NZ

[nzpeterb]

Phil and John,

Thanks for the replies.
I will definitely go with stainless bar.
Still looking at options for the bearings including nylon or a needle roller option. Both could use seals to keep the bearing/bush clean. Roughly the same design as my Gas Gas. Just need a bit more time to sort the solution.

Regards,

Peter.

[hoveactually]

I agree with John Wakefield on use of new metalastik bushes and plenty of grease on the spindle on reassembly. If you want to be sure it will never jam again, simply loosen & rotate the spindle once a year!

In the case of my TDS the spindle, when the nuts are tightened, locks the bush inner metal sleeve to the frame & engine mounts; the rubber insert provides (and resists to a degree) the movement of the swingarm. If you use a nylon bush then you will need to sort spacers/seals to give required clearances to allow the swingarm to move freely! Seems an unnecessary complication for something that has worked so well for many years.

I have recently replaced my metalastik bushes using sockets to push out/in the bushes. I was lucky I had a socket that was a nats whisker smaller than the bush sleeve outer and another that was a nats whisker bigger to push into. See 1st photo. In the absence of a 10 ton press a big vice will do the job.

To ensure I didn't push the metalastik bushes in too far I machined a piece of aluminum bar to act as a stop for the outer metal sleeve with a big enough recess to absorb the projecting inner metal sleeve. 2nd & 3rd photos.

[nzpeterb]

Thanks for your contribution.
I appreciate the detail confirming the inner sleeve of the bush is needed to ensure the swing arm shaft is locked up tight.
Now I understand this I will likely go for the original bushes but with a stainless steel shaft.
Regards,
Peter.