Excelsior Universal 125cc - Rear Plunger

[iansoady]

In my experience, cutting the spring alone won't release the unit. Go for the central pillar. If you use a thin cutting disc in an angle grinder you should be able to do it with minimal damage to the spring by going in at an angle between 2 coils. However, you'll still have spring pressure so you may end up cutting the spring as well.

[DELONSTAINWALL]

Thank you, John. K and members,
Looks like my work is cut out for this project. Will let you all know how I go with  Brexit or no Brexit.

Delon

[DELONSTAINWALL]

Hi Members,

Cutting the top large spring did not help I still couldn’t take it out as the vertical tube feels stuck to the centre rod. Any further advise? Should I cut the rod next?

Delon

[john.k]

Isnt there a pinch bolt retaining the rod at the top mount?...isnt the bracket slotted to the hole ,so the rod can be released by opening out the slot with a chisel or tapered drift?...............IMHO,you need to free up the top mount,slide the rod upward enough to clear at the lower end,twist sideways ,and pull the rod down..............cutting the rod works for the immediate situation,but then you have one more part to find,or make..............

[Rex]

Hi Members,

Cutting the top large spring did not help I still couldn’t take it out as the vertical tube feels stuck to the centre rod.

I can't visualise the design of this set up. On the ones I've worked on the "vertical tube" is the "centre rod", and the axle carrier casting slides up and down on the centre rod. Does this centre rod move in the top and bottom lugs at all?

[iansoady]

Hi Members,

Cutting the top large spring did not help I still couldn’t take it out as the vertical tube feels stuck to the centre rod. Any further advise? Should I cut the rod next?

Delon

That's exactly what I've been telling you.

You'll almost certainly find that the central rod is seized in the slider which is why you can't remove it in the conventional way.

BTW is it a problem on both sides or just one? On my Norton, one side came apart relatively easily so it was a simple matter to see what was going on.

[john.k]

Rex is quite correct........the whole unit .rod and all should slide upwards through the top mount ,when the bottom bolt and top pinch bolt are out............you should be able to remove the whole plunger unit and rod in one piece,then when out,unscrew the end caps of the plunger unit to free the springs........................unless someone has welded the top mount and rod together...........then you must pray for a poor weld ,which can be broken after a bit of grinding............ian ,this unit is quite different to a Norton plunger,inside out ,as it were.

[iansoady]

I may be missing something (often the case) but:

1. There is no upper pinch bolt evident on the photos.
2. Even if it were "inside out", it's obvious the slider is seized onto the central spindle: "the vertical tube feels stuck to the centre rod"
3. I can see no way of removing it other than cutting the central spindle.
4. The only part small enough to slide through the top mounting is the spindle. So I can't see how "the whole unit .rod and all should slide upwards through the top mount ,when the bottom bolt and top pinch bolt are out."

I will of course look forward with interest to see how the saga develops. And of course am happy to own up to any errors in my recommendations. Having said that, suggestions on this forum to me to "cover the whole thing with a sheet and lever it out" when I was struggling with the Norton would have probably resulted in damage to one or more of my hands, the bike or surrounding items.

I appreciate this is not a Norton although plunger systems in general tend to follow a very similar pattern. I do bow to anyone here who has direct experience of the Excelsior layout. Part of the problem is possibly the terms being used.

[Grunt]

I’ve been reading this thread on and off as it has progressed, I have had absolutely no experience of plunger type suspension. What is confusing me is that unless I’ve missed it no one has mentioned spring compressors. Ive no idea what the cost but they are fairly easy to make from lumps of ally  and stud iron.

[Rex]

suggestions on this forum to me to "cover the whole thing with a sheet and lever it out" when I was struggling with the Norton would have probably resulted in damage to one or more of my hands, the bike or surrounding items.

Must be rather different to my A7 then. I did cover the assembly with old carpet and pushed it out when I was disassembling it, and rather than bits of metal flying around the workshop there was nothing but a muffled sound of springs hitting metal (frame lugs) as the tension was released. On instructions from the A7-10 forum I read that it's possible to replace said springs by hand, and indeed it is. A bit of a heavy push, but entirely possible.
The springs aren't under tremendous tension when in place as they only need compressing an inch or so to replace them.
It's not like they're a foot long and compressed down to three inches, which really would be potentially dangerous!

[DELONSTAINWALL]

Thank you to all for your input on this.
There is no pinch bolt on this plunger as I have taken them out top and bottom. I have tried left- and right-hand plungers and they have the same symptom. I believe the rod is seized into the sleeve. If I cut the rod, I will need to find a replacement which is going to be hard for me. iansoady Yes "the vertical tube feels stuck to the centre rod". Any further advise?
Delon

[john.k]

The only pics I can find online are a 1954 Universal in pieces,and its clear the rods have a central spring boss added,probably threaded on..........so cutting the rod isnt a total problem,as its just a rod .........but from the pic I can see that nothing had to be cut to remove the units.........unfortunately the pics are not all that clear,but clear enough to see that my & Rex s description is substantially correct...............my suggestion now is to take the frame etc to someone who has mechanical experience and preferably old bike experience,and person will immediately see whats wrong,which I am beginning to suspect is weldmetal done by a bodger............the Pics are on Sheldons.

[iansoady]

Must be rather different to my A7 then.

It must be. The springs needed compressing by between 2 & 3 inches to get the assembly into place. Even putting my (substantial) weight on the main spring only compressed it about 1/2" or so - there's absolutely no way "hand pressure" would have managed it.

I think Norton designed it to be relatively uncompliant - although I have found the system to be quite effective on the road.

John - do you have a link to the picture which may help the OP? With mine, I decided that it was better to sacrifice the rod, which is a simple part, rather than risking damage to the slider which is not. Cutting the rod on the Excelsior will allow the whole lot to be removed from the frame. My new one cost me only £20 to have made (in fact I later discovered that RGM actually supply them for £30). I cannot see that the Excelsior one would be hugely more than this.

There are only a few ways a plunger system can work and as far as I can see all must involve a central shaft ("bearer rod") with a sliding member carrying the wheel spindle. There must then be springs constraining its movement, either internal as the Excelsior seems to be, or external as on the Norton. I would imagine that the Excelsior springs are held by the hexagons apparent on the pictures and that these probably unscrew to release the tension on them. But of course the external springs have been fitted (the internals maybe vanished years ago), complicating the whole matter.

I'm also not clear whether both sides are seized or only one.

Regardless, this is an interesting saga and I look forward to a resolution and all being revealed.

[DELONSTAINWALL]

Hi Ian and members,

Both sides are seized.
Ian, can I please have details of where I can buy the centre rod please?
If I can get the rods x 2. I will cut the ones I have to take the plungers out.
John K, I believe this bike has been modified to take 1 passengers hence the outer springs on the plungers top and bottom and passenger leg rest on the frame.   

Thank you.
Delon

[R]

Ian was talking about the centre rods for Nortons.

You likely will have to get excelsior ones made up, although they are nothing particularly fancy. ?