Author Topic: Excelsior Universal 125cc - Rear Plunger  (Read 3395 times)

Offline DELONSTAINWALL

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Excelsior Universal 125cc - Rear Plunger
« on: April 03, 2019, 01:10:15 AM »
Hi members,

I am about to work on an Excelsior Universal 125cc. That is for respray and bring it back to life again. Can someone advise me on how I could take out the rear plunger. There is one large spring on the top and on the bottom a smaller spring held onto the bike frame by two small bolts top and bottom. Any advise on how to take this out will be great.

Thank you, Delon




Offline R

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #1 on: April 03, 2019, 03:34:27 AM »
The way these usually work is that you remove the bolt top and bottom, and knock the central shaft upwards,until the sliders and springs can come out, sideways
WARNING - they can potentially come out at lightning speed, and do some serious damage. !!

Wrapping them in a (strong) towel or blanket so they can't escape is a good idea.
As also is lashing them with ropes, so they can't escape far.

Inserting them back in is an interesting exercise also, they usually have to be compressed with a threaded rod and nuts and washers,
wangled into place and the nuts eased off so they slot into position.
WARNING If they escape they can do some real damage.
The aforementioned towels blankets and ropes are some insurance against this.
Never stand in the line of fire, as it were...

Offline R

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #2 on: April 03, 2019, 03:36:57 AM »
P.S. There would have been some covers over that top spring ?

Rubber bellows type, perhaps ?
Possibly also over the lower one ?

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #3 on: April 03, 2019, 03:44:58 AM »
HI there

Really appreciate your reply.

Unfortunately, I had tried to do exactly you have described and the central shaft does not want to move upwards. (please see attach picture)

Thank you
Delon




Offline R

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #4 on: April 03, 2019, 06:58:23 AM »
Mmmm, maybe Excelsior don't quite use the usual system of the central rod in these.

What happened when you tried your rubber or hide mallet to tap this upwards ?
That looks like a rather slim nut at the inside base there, could this be undone with a very slim spanner and used to pull the rod upwards ?

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #5 on: April 03, 2019, 09:40:20 AM »
I seem to remember that the Excelsior system was back to front compared to the common BSA plunger system.............in fact they used the same system as Indian,where the axle mount is connected to the outer cover,not to an internal slider..............as to removal,it certainly looks as though the whole unit with rod is slid up through the top mount,until it clears the lower mount.

Offline iansoady

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #6 on: April 03, 2019, 10:19:39 AM »
Hi Delon.

I had a similar problem with my Norton ES2. The saga is here: http://classicmotorcycleforum.com/index.php?topic=5700.0 - it may be helpful to you.

Be very careful as those springs can pack quite a punch......
Ian
1952 Norton ES2
1982 Moto Guzzi V50

Offline Rex

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #7 on: April 03, 2019, 03:50:14 PM »
I seem to remember that the Excelsior system was back to front compared to the common BSA plunger system.............in fact they used the same system as Indian,where the axle mount is connected to the outer cover,not to an internal slider..............as to removal,it certainly looks as though the whole unit with rod is slid up through the top mount,until it clears the lower mount.

I have an Indian and the axle is connected to an internal slider. The covers are just chromed MS. The Indian plunger assy needed the threaded rod tool to compress the springs enough to start the threaded bottom cup, but my BSA A7 just needed a hefty push down to get the springs etc back into place. Hard push down, but it can be done easily enough.
On the BSA the threaded column was punched down through the slider after all the three bolts (top middle and bottom) were removed. I covered it in a piece of carpet after hearing horror stories of springs sticking into ceilings, but it was nothing like that ferocious.

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #8 on: April 03, 2019, 10:30:31 PM »
Thank you, Members,
R, When I got this, it had no rubbers on the plunger springs top or bottom. R, the only nuts on the plunger is the two large chrome nuts and the two holding the plunger top and bottom. Iansoady thank you for the pic, didnít help.
The plunger moves up and down the shaft. The centre rod does not move and I have tried hitting it out from the top (large spring end) and from the bottom (small spring end) but it feels like I am hitting solid metal. I donít want to damage the rod by hitting it harder than what I have. Other pic of this motel does not have springs on them just the plunger only. When I compress the large spring the centre rod does not move.   
Please advise what I can do next Members.
 

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #9 on: April 03, 2019, 11:52:03 PM »
The outside springs are not original,been added to modify the unit....................the original setup is the centre part with springs enclosed in the unit by the two threaded end nuts,and the rod fixed in the frame................with a bodge ,its always possible the centre rod has been welded or brazed into the frame..................but first I would clean up and wire brush(sandblast better) the frame to rod mount area.,so you can see whats going on..............the rod may be threaded at the bottom,and just needs to be turned out to release the unit...........................my thought for the day.......a thoroughly bodged british bike is a formidable adversary.

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #10 on: April 04, 2019, 12:20:32 AM »
Had a think about that .........its going to very difficult to disassemble.................firstly,the rod has a boss in the middle ,inside the springbox,so it cant be driven thru.........secondly,the added springs make the unit near impossible to dissassemble in the intended way,which is for the spring unit to be pushed upward until the rod clears at the lower mount,twisted sideways enough to clear the lower frame ,and the whole unit pulled out downwards...............note that the correct springs(inside the box)play no part until you unscrew the end caps...................BUT......the very solid exra top spring makes that method very difficult...........the whole unit is going to have to be compressed upward,and hopefully ,doesnt become coilbound before the lower end clears the frame.................SO.....dont hit the rod,it cant be driven anywhere ,and will end up mushroomed..............

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #11 on: April 04, 2019, 12:51:19 AM »
Thank you, John.K and members,
I have compressed the large spring (top end) with the plunger upward but I cannot get the clearance to get the centre rod out of the lower frame. See photo attached. Please advise next step. Thank you Delon

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #12 on: April 04, 2019, 01:28:46 AM »
I think the movement inside the spring box is the problem................I would compress the springbox/plunger upward by using a bearing puller under the lower springbox nut,and two long threaded rods to the top mount.............I dont know what tools you have,but with minimal gear,i think you might have a two leg puller you could use to force the rod up enough to clear the lower mount.............as I said ,hammering is no good,as the spring just pushes back.............I have tons of OTC puller stuff for industrial use,which you could use ,except you are 3,000 miles away...................I hesitate to advise cutting the upper spring,because it may be the spring out of the box,but if that upper spring is cut away ,the whole unit will easily slide thru..........I dont know how easy parts are to find.,but dont wreck anything that cant be replaced.

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #13 on: April 04, 2019, 02:30:00 AM »
Thank you, John. K
The top (large) spring and plunger moves up about 2cm when I compress the spring. I still need for the central shaft to move up witch it doesnít. It seems like the sleeve and the central shaft on top and bottom side is one peace. When I compress the spring, the central shaft does not move. only the plunger moves up when compressed up.
Please advise.
Delon

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #14 on: April 04, 2019, 03:05:00 AM »
All I can see needs to be done is to force the springbox assy upward as far as possible,using a bearing puller under the lower nut,then you need to force the rod upward as well......................however ,if you have a bearing puller ,you can also try closing it onto the shoulder in the rod we can see in the latest pic..........I realize this may mean you need two bearing pullers ,so as to leave one under load ,while positioning the other on the rod..................another point...does the rod have a threaded hole in the top ......it may be possible to insert a bolt and spacers to maintain position while you change pullers over................as I said ,a last resort will be cutting the spring away.