Author Topic: Plunger seal back of clutch  (Read 1664 times)

Offline bsarider

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Plunger seal back of clutch
« on: 17.05. 2011 12:59 »
Could the forum tell me how to change the seal in the back of the clutch where the mainshaft  for the gearbox pokes through on a 49 plunger. I have the new seal but the old one is revited in due to the clearances to the clutch and rear chain can I drill the old revits out and use a pop revit gun to fix the new seals or would some small m4 nuts and bolts do,has anyone done this? Alan

Offline trevinoz

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Re: Plunger seal back of clutch
« Reply #1 on: 17.05. 2011 23:02 »
Just pop rivet the retaining plates back in place. If you don't have sealed rivets a dab of Silastic or similar will do.
 
     Trev.

Online Brian

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Re: Plunger seal back of clutch
« Reply #2 on: 18.05. 2011 00:30 »
Alan what type of seal do you have. The original was some sort of material thing, use a modern seal. If memory serves me (which it probably doesnt) you need a seal with 35mm OD and 17 ID, check those dimensions though as I could be wrong.

When you put the gearbox back on wrap some plumbers tape around the spline on the gearbox main shaft and put a smear of grease over that. This will stop the seal being damaged as you slide the gearbox back into place. When the gearbox is back on the motor simply remove the tape.

Offline bsarider

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Re: Plunger seal back of clutch
« Reply #3 on: 18.05. 2011 19:21 »
Thanks for your replys, pop revits and tape it is. Alan

Offline Resto-Rob

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Re: Plunger seal back of clutch
« Reply #4 on: 31.08. 2014 19:10 »
I am having the same problem with my seal and was wondering if you could tell me which way the retaining plates for the seal goes? Is the dished plate on the gearbox side or clutch side? And which way does it face? Thanks :)
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1953 BSA A10 Plunger
1927 BSA S27
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Online morris

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Re: Plunger seal back of clutch
« Reply #5 on: 31.08. 2014 21:43 »
Hi Rob, dished plate goes on as on the picture.
I have turned a ring for the backside of 49mm OD, 30 mm ID and 3mm thickness, drilled and tapped with 3 holes 5BA. This saves me from drilling out the rivets when changing the seal in the future.
Best is also to take out the gearbox main shaft when putting the box back on, and slide in the shaft afterwards. The angle's to steep to get it in without damaging the seal
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
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Offline Resto-Rob

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Re: Plunger seal back of clutch
« Reply #6 on: 31.08. 2014 22:33 »
This is great! Thanks.
I think i will need to build a new "dished" retainer as mine has rusted and is very thin.  Any reason why it has to be dished?
Does anyone know where to get new replacement retainers?
When life throws you a curve..... lean into it!!
1953 BSA A10 Plunger
1927 BSA S27
Austria

Online morris

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Re: Plunger seal back of clutch
« Reply #7 on: 31.08. 2014 22:57 »
Not sure, but I think it's for the oil that runs down the backplate not to go via the shaft into the clutch basket. There should also be a sealed cover on the other side of the clutch for that purpose. Mine is missing, and it seems to be a hard to find item...
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
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Offline duTch

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Re: Plunger seal back of clutch
« Reply #8 on: 01.09. 2014 05:28 »

 I carved a hole and grafted in a plate from an A65, so I don't need to pull  the whole power unit out to even just look at the sprocket
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online orabanda

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Re: Plunger seal back of clutch
« Reply #9 on: 01.09. 2014 06:11 »
Dutch,
That's such a great idea!

You should be made an honourary West Australian!

Richard

Offline Resto-Rob

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Re: Plunger seal back of clutch
« Reply #10 on: 01.09. 2014 07:28 »
Thanks for the feedback guys :) Dutch, im not sure what you mean?! Any chance of a photo of your mod??
When life throws you a curve..... lean into it!!
1953 BSA A10 Plunger
1927 BSA S27
Austria

Offline muskrat

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Re: Plunger seal back of clutch
« Reply #11 on: 01.09. 2014 09:25 »
I had thought of that mod too for ease of changing the sprocket and g/box seal.
here's a few pics I got on the net.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

Online morris

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Re: Plunger seal back of clutch
« Reply #12 on: 01.09. 2014 09:40 »
Great idea. I think I know on what I will be spending my spare time the next few weeks... *wink2*
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
Belgium

Offline chaterlea25

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Re: Plunger seal back of clutch
« Reply #13 on: 01.09. 2014 12:41 »
Hi All,
I lik the centre photo where the additional support bearing has been added on the A65 engine  *smile*

I have modified a couple of Tiger cub cases in a similar fashion as on these the crankcases need to be split to change the gearbox sprocket  *eek*

John
1961 Super Rocket
1963 RGS (ongoing)

Offline duTch

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Re: Plunger seal back of clutch
« Reply #14 on: 01.09. 2014 12:57 »

 did a reply, but it must've gotten lost- hate doing it again..!

 Fairly sure I posted a pic or two on here somewhere before, can't find them now...but the result is much like in Muskys first and third pics, also noticed that outrigger bearing
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia