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Mk3 Swinging arm, The next problem.....

Submitted by alan_hesslewood on Wed, 02/09/2020
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Commando

So the swinging arm is finally on the cradle with the pin installed and the cotters fitted and tightened up, next the welch plugs. After fitting the pre-soaked felts, it has become apparent that the welch plugs will not seat properly in their recess as the swinging arm pin seems to be too long. Whacking it to facilitate its fitting only results in a felt disc with a hole punched in it. So i`m guessing I need to remove the swinging arm pin again to grind some off the ends (pain in the @r$*) or fit them with some silicone sealer as I`ve heard of previously (not so easy with all that oil about). Anyone else had the same thing recently?

Regards, Al.

Felt disc

 

S/A pin

 

 

 

 

 

 

 

 

 

Submitted by andrew_mackenzie on Wed, 02/09/2020

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Al,

There are two spindle lengths - 6.35” and 7.0”. The Mk3 has the shorter spindle.  There are bush lengths to suit.

i elected to dispense with the felt plugs and washers, fit the longer bushes that were shortened to align with the welch washer abutments, and fit the earlier end caps, o-rings and long securing bolt. This set-up provides a greater 140 oil reservoir at either end and permits simple topping up.

Andy

Hi Andy & John, thanks for your advice.

It seems odd that the spindle is too long as it has the recesses for the cotter pins that only the Mk3s have so is surely intended for fitting to a Mk3? I have just tried the earlier end caps with the long thin through bolt as I found one on the shelf but there is nothing for the O rings or end caps to sit in to locate them on the Mk3 swinging arm unless their outer diameters can be reduced. Did you have to do that Andy? Its the same on the other Mk3 i`m working on at the moment so on that one I have just sliced a bit off each end of the spindle with the angle grinder and will try that once I`ve got the ends squared up.

Regards, Al.

Submitted by john_holmes on Wed, 02/09/2020

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On my MK3 swingarm I have the old end caps too, put bike on side stand, remove grease nipple and use oil can to fill using nipple hole with regular stops to allow bubbles to appear.

Submitted by ashley_cutler on Thu, 03/09/2020

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The spindle could be for the intermediate cradle, that has cotters like the MK3 but allows the fitting of the pre-MK3 swingarm, and the gearbox adjuster. 

Submitted by john_holmes on Thu, 03/09/2020

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Yes most spindles have the slots for the cotter pins now, and new pre MK3 cradles now can have the cotter pin tubes.

I checked back through my receipts and found that the spindles came from our own NOC shop. Looking again on the website they have 3 different spindles, all with the cotter slots but all 3 too long to fit straight into a Mk3. So I guess the answer is, if you need a Mk3 swinging arm spindle and don`t mind a bit of grinder action then the NOC shop ones are the cheap option but if you want something ready to fit straight from the box, an AN etc part is required & I really should make sure I`ve got my glasses on when ordering parts!

Thanks again for your help everyone, Al.

Submitted by andrew_mackenzie on Sat, 05/09/2020

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Al,

Looking again at your first photo, are your felt plugs impregnated with grease or oil - it looks bit like LM grease?  If it is grease, you should really use 140 grade oil to avoid clogging the oilite bushes.  The Castrol straight 140 oil I bought is a much more golden brown colour than your felt appears top be.

Andy

Hi Andy,

I have used SAE140 oil from Whitham oil & paint, my local supplier at Lincoln.

I still don`t understand why new swinging arm spindles are being made with the cotter pin slots for Mk3 models when they are too long to fit Mk3s, seems crazy to go to the extra time trouble & expense machining the slots when they can`t be used unless you grind a quarter of an inch or so off each end of the spindle which is what i`ve had to do with mine. what a pointless faff!

Until the next problem......Best wishes, Al.

Submitted by stan_thomas on Sun, 06/09/2020

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Last spindle I bought had both cotter pin slots and 1/4 UNF centre bolt hole. Seems they just set the machine to make a universal fitting - the joy of CNC.

I gave up using those Welch plugs 'cos I could never get them in even with the right spindle and bushes. Not keen on hitting my bike with a hammer either. Gone back to the earlier end caps with filler hole and long thin bolt. So longer pin with Mk3 cotter slots is exaclty what I want.

Oh, and EP90 oil is preferred, especially if you can top it up.

Hi Stan,

If your bike is a Mk3, did you presumably have to reduce the outside diameter of the "bolt through" end caps to get them to locate in the outsides of the smaller Mk3 swinging arm recesses? If so, just wondering how you got them to seal as the longer swinging arm pin stops the end caps from entering the recesses deeply enough to compress the O rings. 

Regards, Al.

Submitted by andrew_mackenzie on Sun, 06/09/2020

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Hi Al,

In my case, yes, I had to reduce the diameter of the end caps. I used a grinding wheel and the trickiest part was making sure I only took enough material off to get a close sliding fit, while keeping the caps round.

I got a pair of the longer bushes and reduced their length so that they aligned with the Welch washer abutment and found an o-ring size (from an Aldi assortment!) that fitted nice and tight in the bore and would be compressed by the end caps against the abutment and ends of the bushes.  

On the R/H side, the end cap is thicker For the nipple thread and sits pretty much flush with the end of the swinging arm. On the L/H side, the thinner end cap sit inside by about 2-3 mm, so my intention is to apply a thinbead of silicon sealant around the edge of the cap purely to hold it in place if I remove the R/H cap for any reason; e.g. when topping up. The sealant will also stop corrosion on the swinging arm and ground cap edge.

This is my solution anyway and it worked fine on a previous Mk3 years ago.

Andy

Submitted by alan_hesslewood on Sun, 06/09/2020

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Hi Andy,

Thanks for the detailed explanation of work required to fit the earlier end caps, it kind of makes the correct length pin from AN start to sound better value for money than first thought! I guess it all comes down to time verses money. My rebuild has ground to a halt again already as I`ve chipped the paint on the swinging arm again and now I`m thinking about stripping the whole chassis and repainting it in something tougher if I can find something better that is. Think I`ll start a new thread on chassis paint, Oh the hours of fun.......

Thanks again for your input, Regards,Al.

 

Submitted by ashley_cutler on Mon, 07/09/2020

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An oilite bush when filled with oil is lifed item, it does not need topping up. However, it causes no harm to keep the whole spindle wet as it will aid removal.

For sealing in the end caps, remember there are two types of sealant, adhesive and non-adhesive, make sure you use the adhesive type. 

 



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