Swinging arm question

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EVguru
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Re: Swinging arm question

Post by EVguru »

I've got material in stock, but no ready made parts. The bushes don't take long, but the spindles are quite a bit more work.
Paul Compton
http://www.morini-mania.co.uk
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harrymuffin
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Location: west midlands

Re: Swinging arm question

Post by harrymuffin »

The best material for the swinging arm bushes is made by a firm called Igus and have an office in Northampton. They do a range of advanced plastics and on their advice years and years ago was to use Iglidur M250 which is supplied to farm machinery manufacturers owing to farmers not being mechanically minded and were not at the front of the queue when doling out brains. This material is not hydroscopic like nylon and ptfe and the ideal lubricant after initial running in is water and as their is plenty down by the swinging arm, is all you need especially if you have great sets fitted. I have just rebuilt a Morini that after 20 years still had no play in the swinging arm and was never lubricated as I have rear sets fitted and so no grease nipple. The material on bedding in deposits a thin layer of 'plastic' onto the shaft so that instead of metal to plastic rubbing you have 'plastic' to 'plastic' rubbing together and with the addition of a bit of water when to rains then an almost perfect bearing set up. See their blurb if you want more information. They even do bushes that fit direct into the swinging arm and the spindle if you have a new one will fit without having to arse about reaming as a tight initial fit is desirable.
I still have a spindle and bush kit for the K2 if you want it as I made two spare spindles when I had a K2. This set up is really fit and forget and it is cheaper to skim the existing spindle to remove ovality usually to 17.5mm and then turn up the bushes to suit. I have rebutted the swinging arms on the off road bikes that have 16mm spindles to start with so reducing the spindle to reduce ovality does not compromise structural integrity.
For getting the old bushes out I made up a puller and although some have 'rusted in have never had to resort to using a hacksaw to split the sintered iron ones originally fitted.
penman
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Joined: 08 Mar 2016 09:20
Location: Milton Keynes, UK
Location: Milton Keynes

Re: Swinging arm question

Post by penman »

An update. I had to go up to NLM today for a different reason and the temptation to just buy a set of new bushes was too much for me, so that's what I did. The new bushes are phosphor bronze and the spindle is stainless steel.

After all the horror stories I've heard, the old bushes came out quite easily, using a long bolt and various washers and spacers. I actually used a Whitworth bolt which seemed kind of suitable for some reason! I used the same method to put the new bushes in. They'll need a light reaming but I didn't have time to do that and I didn't want to rush it.

The new spindle is slightly different in that it has tapped holes for grease nipples at BOTH ends - my old one just had a nipple at the r/h end. The l/h nipple was on the swing arm, with a hole in the side of the l/h bush. I suspect the rear cylinder exhaust header might obstruct that l/h grease nipple. We shall see!

If it's lucky, this swing arm might get a coat of paint before it goes back on....
1984 Moto Guzzi V65
1969 Honda CB450
1975 Triumph T160 Trident
2019 BMW F750GS Sport
1978 Morini 500
penman
Posts: 325
Joined: 08 Mar 2016 09:20
Location: Milton Keynes, UK
Location: Milton Keynes

Re: Swinging arm question

Post by penman »

harrymuffin wrote:The best material for the swinging arm bushes is made by a firm called Igus and have an office in Northampton. They do a range of advanced plastics and on their advice years and years ago was to use Iglidur M250 which is supplied to farm machinery manufacturers owing to farmers not being mechanically minded and were not at the front of the queue when doling out brains. This material is not hydroscopic like nylon and ptfe and the ideal lubricant after initial running in is water and as their is plenty down by the swinging arm, is all you need especially if you have great sets fitted. I have just rebuilt a Morini that after 20 years still had no play in the swinging arm and was never lubricated as I have rear sets fitted and so no grease nipple. The material on bedding in deposits a thin layer of 'plastic' onto the shaft so that instead of metal to plastic rubbing you have 'plastic' to 'plastic' rubbing together and with the addition of a bit of water when to rains then an almost perfect bearing set up. See their blurb if you want more information. They even do bushes that fit direct into the swinging arm and the spindle if you have a new one will fit without having to arse about reaming as a tight initial fit is desirable.
I still have a spindle and bush kit for the K2 if you want it as I made two spare spindles when I had a K2. This set up is really fit and forget and it is cheaper to skim the existing spindle to remove ovality usually to 17.5mm and then turn up the bushes to suit. I have rebutted the swinging arms on the off road bikes that have 16mm spindles to start with so reducing the spindle to reduce ovality does not compromise structural integrity.
For getting the old bushes out I made up a puller and although some have 'rusted in have never had to resort to using a hacksaw to split the sintered iron ones originally fitted.
I wish I had seen your post earlier! As you'll see from my previous posting, I have already gone down the phosphor bronze route. I will bear this in mind for the future though.

As for the K2, it's OK at the moment, having done a very low mileage, but I might be interested in your spare set to have up my sleeve - PM me with price, etc. Many thanks!

Regards,
Joe.
1984 Moto Guzzi V65
1969 Honda CB450
1975 Triumph T160 Trident
2019 BMW F750GS Sport
1978 Morini 500
harrymuffin
Posts: 292
Joined: 07 Apr 2014 16:06
Location: west midlands

Re: Swinging arm question

Post by harrymuffin »

Shame about that. Phosphor bronze is not very good when bearings are boundary lubricated as anyone who has a Velocette will confirm. The grease squeezes out from where you need it so metal to metal rubbing and as the bronze wears into to fine particles it mixes with the grease and produces a fine grinding paste. Phosphor bronze bearings only really work where hydrodynamic lubrication is in effect - oil. It does not need an oil pump just a head of oil as steam locomotives employ on their wheel and connecting rod bearings. I had the oil pump on a mini pack up but the engine still ran and with the the rotation of the crankshaft producing an oil pressure on the gauge of 20psi, I only found the pump in bits when I stripped the engine with no damage to the main or big end bearings.
You could still use the Igus bearings as they do do the material suggested as a direct fit 24o/d x 18 i/d but you have to use two in each side as they are made in 20,30 and 40 lengths. If you use two 30's then you can reduce the length in the lathe such that they slightly protrude and then fit to the frame and you can do away with the washers. Stainless steel and P.B are not recommended in basic engineering practice as the materials tend to be incompatible just as S.S should not be used for the exhaust nuts into the aluminium heads as the materials fret, the combination is banned in aero engineering.
As I said in my previous post - and apologies for the spelling mistakes and wrong words creeping in, spell checkers are a pain - the bike I have just rebuilt had no wear on the spindle and had to be eased out of the frame, I have only replaced the bushes as the frame was sand blasted prior to repainting and did not want any traces of sand in the bushes for obvious reasons.
I will sort out the K2 spindle kit and let you know.
norbert
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Re: Swinging arm question

Post by norbert »

Dieter Hoffman/germany (Morinicorse1@aol.com) sells a needlebearing axle kit for 120€
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Re: Swinging arm question

Post by EVguru »

norbert wrote:Dieter Hoffman/germany (Morinicorse1@aol.com) sells a needlebearing axle kit for 120€
Not really a good idea.

The housings are not well enough aligned due to welding distortion.

Needle roller bearings are not well suited to low angle reciprocating loads.

If you are going to use needle rollers, they need to be the cageless or 'crowded' version.

I bought a frame that was fitted with one of these kits. Only one bearing on each side was taking the load (distortion) and just five rollers were loaded. You could see the Brinelling on the spindle.

Having said that, this solution, or even the OEM cast Iron bushes are likely to see the owner dead and buried before they wear out given the demographic.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
penman
Posts: 325
Joined: 08 Mar 2016 09:20
Location: Milton Keynes, UK
Location: Milton Keynes

Re: Swinging arm question

Post by penman »

Many thanks to all for the numerous replies here, there is a wealth of information and experience showing through! As usual for me, I dived in a bit too soon and I'll have to live with the phosphor bronze / stainless steel solution. Realistically it should be fine and if I keep it lubricated it'll probably see me out!
1984 Moto Guzzi V65
1969 Honda CB450
1975 Triumph T160 Trident
2019 BMW F750GS Sport
1978 Morini 500
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