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Rayp

Hayter 21 axle and clutch assembly

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Having spent some time getting the engine to start easily, I found that I had poor drive to the wheels and suspected the clutch needed adjusting as the 'wheel drive belt' seemed OK.  I  removed the wheel, hub and chainguard and after removing the Hub (photo2) I found what appeared to be two worn grinder disks (photo 1) which are not shown in the Spare Parts Book. I am wondering if these should be there or whether they are the result of a 'cowboy fix' in the past.

I addition the Drive Chain is filthy and I need to remove it and clean it but cannot see a revvable link or how otherwise to remove and refit it.

Any help would be most appreciated. 

P1010334.JPG

P1010335.JPG

P1010333.JPG

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It's a bodge Ray. Have a look through this Thread for pics of what it should look like OSPREY

I've sent you a copy of the Manual which should cover it (via PM)

As for the link in the chain, I think I see it arrowed here -

Chainlink.JPG.ea8f0b91bc19c80f750731bfdfe80f33.JPG

 

Open end is usually on the trailing side of rotation .

You'll probably need to obtain and bond new friction pads onto the Toothed Clutch Plate. 

A link to the people I've used in the past if it helps-    Friction .

 

Bonding them well requires scrupulous cleaning and a good bonding resin like Araldite Original ( NOT the 5 min stuff).

I'm sure Wristpin, Nigel and others will offer more experienced options and advice on that and the machine.

Edit in RED

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Setting up those clutches is a bit of a black art. In the 80s the roving Hayter Service man used to have an Osprey / 21 axle assembly set up on the bench in his high top van and ran an impromptu service course on site.

There should be a thick friction lining bonded to the large sprocket. I believe these are still available from an aftermarket supplier of friction materials.

However, from your image, it appears that there is a lot more to be done. Looking at the relationship between the bush and the axle it appears that one or the other - or both, are badly worn. I think that a complete strip and assessment of the axle is required.

 

https://www.dropbox.com/s/i5ys5rh1mdtrwc4/Hayter 21%2C Ospey Clutch adjustment0001.pdf?dl=0

 

https://www.dropbox.com/s/a2gbo2quuaymiea/Hayter Osprey and 21 0001.pdf?dl=0

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Thank you all once again - I would be lost without your help and advice!  I  had forgotten I do have an axle from an old Osprey and will have a look at it in the faint hope that any of the parts are usable.  I can see the removeable link now that Richard has pointed it out - the Sun must have been in my eyes when I took the photo!

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Hi again Richard,

I tried to message you but the System would not let me add photos so I have put them here.  This is the chain on my Osprey axle.P1010337.JPG.eb1ef6baf4d4d5d9122a2008c1db0971.JPGP1010336.JPG.e5759ba56b609ff5ae6aa6884769dc1c.JPG

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Yep!, Reckon that is another bodge to eliminate chain slack. May have fitted the half link in situ in consideration to the points mentioned in my PM regarding the Axle movement restrictions with Keyway and Circlip.

Other more experienced Members familiar with this model may offer more accurate/beneficial advice than I, but my opinion of the amount of slack in the chain is not of great significance. If you refer to the earlier image of 'Spot the Removable Link'. that amount of slack is not an issue in a correctly installed set up.

This is because there should be a large 'O' ring fitted around the Chain. My interpretation of the fitting of it is-

- to provide a retaining effect which prevents chain slap against the inside of the Cover Plate

- acts as a grease retainer

- maintains pressure to ensure chain engages teeth on the sprockets efficiently.

My bet is these are missing on both of your machines. If you can carefully measure the outer circumference of the chain/sprockets and post it on here please.

 

At this point, I am not sure of the availability of spare parts are for these, so here is a link for you to make enquiries about any parts we are discussing-

PARTS 

Replacing bronze bushings should not be a problem, as most imperial sizes are still available.

Replacing the Clutch friction material as mentioned in PM-

The thickness was about 5-6mm Woven (probably 1/4" when new).

Not sure if you're buying sheet to cut your own, or having Autoandindustrial to precut for you?. I've shifted these images to this thread, rather than put links in to make it easier. If you're cutting your own, a junior hacksaw will work and lining is safe with no asbestos.

The diameter of the linings are slightly larger than the diameter of the plates either side to ensure even plate wear-

post-94-0-03953200-1403681601_thumb.jpg

 

You should be able to assess measurements from this pic for the inner diameter cutout by comparison with your own plates.

Also gives an idea of the important clearance of the friction lining edge and the proximity of the chain. No grease must be allowed near the lining-   

 

post-94-0-48601300-1403681592_thumb.jpg 

 

Hope this helps and keep at it. 

 

    

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That axle looks to be badly worn and even a new bush won't restore the distance between the two sprockets. I cannot overemphasise that to "get a good clutch" everything has to be right - don't kid yourself that near enough is good enough.

At some point in the production of 21s and Ospreys Hayter used to fit a heavy duty O ring around the chain and sprockets to contain the sag in the chain and scraping the inside of the chain case . Part number 4946. 

Essentials for a good clutch.

No end float on the axle so that no clutch movement is absorbed by the axle shifting sideways.

No radial wear on the axle either where it passes through its bearings in the cross tube or where the sprocket or hub rotate on it.

No bush wear in the sprocket allowing it to "flop" left and right and not run at 90 degrees to the axle.

No bush wear in the hub - same as for the sprocket.

Eliminate wear in the handlebar clutch lever lockout so that the full amount of cable pull is maintained when hand grip is released. There's a fairly simple fix for this.

Get it right and you will have a machine that spins its wheels and drags you along, ignore it at your peril.

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Just had another look at the second chain (on the Osprey). Have a look on the inside of the chain for the split retaining Cotter Ray, right next to the Cranked Link (half).

I think I was wrong and it is correct, as there are the right number of Links in that chain in total (53), so it may have been fitted on the inside edge.

Can't be sure, but I think the chain is 1/2" pitch and a new cottered connecting link is available, as well as chain if required.

 

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Thanks Wristpin - I have checked the axle and bush again on the Hayter 21 and there is 36 thou between the exterior radius of the axle and the inside diameter of the bush.  Do you know what the correct difference should be?  The part number for the O ring is very helpful and I am trying to order one. I will try to adhere to your list of essentials and  look forward to being dragged along as I had to physically help the mower along last week for 3 hours to get a job done (before the inevitable prolonged rains appear!). 

I have looked again at the Osprey chain and it looks like you were right Richard.  I could not see a split retaining cotter using a light and mirror so I hacksawed through the half link, but looking closer at the back of there does appear to be provision for one although nothing came off (or I did not see it if it did!) when I removed the chain which is indeed 1/2"". 

There was no O ring on either the 21 or the Osprey so I am trying to order one.

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2 hours ago, Rayp said:

 

There was no O ring on either the 21 or the Osprey so I am trying to order one.

No real loss with that chain then, looked past serviceable to me. I was looking for the circumference measurement of the chain on the 2 fitted Sprockets, because, believe it or not, I may have just the thing to fit. I need to be sure it will fit without excessive stretch. At least you may have a last resort if the 'O' ring is unobtainable.    

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4 hours ago, Rayp said:

Thanks Wristpin - I have checked the axle and bush again on the Hayter 21 and there is 36 thou between the exterior radius of the axle and the inside diameter of the bush.  Do you know what the correct difference should be?  The part number for the O ring is very helpful and I am trying to order one. I will try to adhere to your list of essentials and  look forward to being dragged along as I had to physically help the mower along last week for 3 hours to get a job done (before the inevitable prolonged rains appear!). 

2

Rain - what's that?

36 thou!!! - far too much. Slide the bushed components onto the axle one at a time and grasp them at 9 and 3 o'clock, if there's any "wiggle room" it's too much. 

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