Author Topic: Excelsior Universal 125cc - Rear Plunger  (Read 20429 times)

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #15 on: April 04, 2019, 04:05:52 AM »
Thank you, John. K and members
From what I can understand are you asking me to compress the plunger as per the larger arrow and then compress the central shaft as per the smaller arrow? pic attached.
regards
Delon

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #16 on: April 04, 2019, 05:49:54 AM »
Yes,there isnt any space there ,but you might be able to get a small bearing separator in under the lower dome nut........and seems you may have to push the rod from the end,but would be better if you could use the shoulder just below the spring........................As to removing the top spring.................it would depend on whether there is a spring inside the unit........remember that upper spring will actually go into the lower side of the springbox..........anyhoo,if the outside springs are extras ,cutting one isnt problematic.......but if they are from inside ,then you will be looking for replacements.

Offline iansoady

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #17 on: April 04, 2019, 10:21:34 AM »
I'm sorry you felt my post (which if you read it was rather more than a pic) was unhelpful. However, if you adopt a similar approach, ie cutting through the central rod (and probably, in your case, the springs) with an angle grinder, you will be able to dismantle it. Having done that, making a new rod will be a simple machining job, and wherever in the world you are springs are easy things to have made.

What you do need to do is to avoid destroying irreplaceable parts like the alloy casting.
Ian
1952 Norton ES2
1986 Honda XBR500
1958-ish Tre-Greeves

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #18 on: April 04, 2019, 11:19:20 PM »
Thank you, John. K and iansoady.
I truly don’t want to start cutting anything if possible. Iansoady any help is good. I may have used the wrong words.
John K I will try doing this on the weekend and let you know how it goes.
I am waiting for the service and parts manual that I have ordered perhaps this will help me?????

Delon

Offline Mark M

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #19 on: April 05, 2019, 02:58:29 PM »
I spoke with an Excelsior enthusiast pal of mine this morning and he demonstrated the finer points (!) of plunger dismantling on an example which happens to be sitting in his kitchen. Once the nuts top and bottom have been removed the central pillar should just knock out, it's that simple. However in reality, the block on which the wheel spindle sits is bronze bushed and is likely to be seized to the column. Due to the construction method you will struggle to get enough heat and lubrication into this area so you may well have to cut the pillar. He says these were originally a surface ground bar which may be hard to find today in an Imperial size but there is a near Metric equivalent which can be used. Since you will have to rebush the block make new bushes to suit.Either way you'll need a friendly engineer to make up the parts if you can't do it yourself!
REgards, Mark

Offline Rex

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #20 on: April 05, 2019, 04:26:17 PM »
Think he'll be lucky to have a bronze-bushed slider on an economy lightweight. Even the mighty BSA used a steel slider direct onto a steel column, but then again steel on steel would be more likely to seize together.
If this was the case, hitting the top (or bottom) of the central column should see the spring compress, but I got the impression that the OP said it was more "solid" than that.

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #21 on: April 06, 2019, 12:08:35 AM »
His whole? problem is the external springs added by a previous bodger........the Excelsior unit should remove easily from the frame,the extra springs are preventing movement ..............there is a truism with british bikes .......smaller the bike,bigger the bodge.........................although the best bodge I have seen is a large torque converter filled with concrete to restore drive in a big tractor........now thats a bodge.

Offline 33d6

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #22 on: April 06, 2019, 03:57:53 AM »
A large part of my so called 'restoration work' is just de-bodging and returning a bike to bog standard.  Then it drives me nuts when people say 'It runs really well now so I think I'll just do so and so and such and such to improve it '. I then watch it all go downhill again. 

Offline Rex

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #23 on: April 06, 2019, 10:08:40 AM »
Almost an impossibility for any bike approaching 80 years old not to have some bodge or other inflicted on it somewhere, even if it's only some ba*tard tapping out a thread to take a metric stud or whatever, or taking a stick welder to the centre stand lugs.
They've spent too long at the "that'll keep it going for another month" value stage for things to be any different.

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #24 on: April 07, 2019, 10:46:47 PM »
Thank you, to all members for your input on this subject.

I have spent several hours attempting to take the plunger out as per your instruction’s members. The only thing I haven’t done is cut the centre rod which passes through the frame. I am sure if I cut this, I will be able to take the plunger out. Tapping the centre rod from the bottom does not help as I believe the rod is seized. I have just managed to get a Pic from a friend of mine Alwyn. Please see attached. The instructions state that remove nut N and tap the centre rod from the bottom. This is not happening to mine plunger. Please advise further?

Best regards Delon, 

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #25 on: April 08, 2019, 12:34:17 AM »
You will have to cut away the upper spring............that is what is preventing you from removing the unit............I would use the oxy,but a 4" angle grinder with a thin cutting disc should demolish the spring without marking the frame........I would not cut the rod,as it likely has a boss in the middle......IE is not a simple rod.......so making one might be a challenge ,or costly if you dont have a lathe.

Offline TGR90B

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #26 on: April 08, 2019, 09:45:35 AM »
I've come in late here, but has anyone suggested pressing the rod out? Hitting a rod or spindle does tend to expand it.
Getting grumpy, but not as grumpy as mini-me.

Offline iansoady

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #27 on: April 08, 2019, 10:05:27 AM »
I'm pretty sure he'll have to do the same as I did. If he uses a thin cutting disc he should be able to cut the central pillar without damaging the spring (too much).
Ian
1952 Norton ES2
1986 Honda XBR500
1958-ish Tre-Greeves

Offline DELONSTAINWALL

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #28 on: April 10, 2019, 04:52:08 AM »
Thank you, to all members for your input
It looks like cutting the top spring or the central shaft is my way out of this?
Any further advise?
Delon

Offline john.k

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Re: Excelsior Universal 125cc - Rear Plunger
« Reply #29 on: April 10, 2019, 10:11:14 AM »
toss a coin.....the spring or the rod?.............Brexit or no brexit...........decisions can all be simplified by a coin toss.