TOPIC:

Firstly: Don't call me Shurley !
There's several issues with retro-fitting an over-flow tank to the original location. Obvious, certainly - but none-the-less:
A) The filler cap location, relative to the tank itself.
The back of the tank needs supporting. Accomplished with a "prong (moulded into the OEM tank) that fits into a support grommet,
C) Orientation and location of the inlet to the tank,
D) A cover securing screw on the OEM cover via a moulded tab on the bottom/front of tank, and
E) The physical size.
I've spent many hours "Google" ing" for a substitute. It continues to elude! The closest I can get is this: A soap dispenser from a Pressure Washer. Won't accept the OEM cover and has no securing points. The port is substantially smaller but could be drilled out a another size or two.

What I did with my original when it started falling to pieces was wrap it all (Less the filler-neck) with 2 layers of 6 0z. Fiber-Glass cloth and resin. The cover didn't fit so made another from a piece of fine metal expanded-mesh. Didn't look too bad, either! Ran that for several years without problems until I found a replacement - cheap ! It's now showing signs of age deterioration. There's several "Plastic" moulding manufacturers in my area that could easily produce these over-flow tanks but the problem is the tooling and set-up costs !!!! Same as CNC'ing a Prototype Cleaning Tool or a Spin-on Oil filter/Cooler ! It's "freakin" costly ! Then there's always a "minimum order" which is also a huge expense.

There's one on ebay UK at the moment, about half the price of the Netherlands one, but very yellowed and as per Scoth's comments could be in any condition, but if you're interested it's eBay item number:352105275080 for 42 quid sterling + shipping.

Richard.

I managed to get an old one on EBay for £38 + postage. Spoke to the chap selling (really nice bloke) and it is dirty but totally sound. Being as it is 90% hidden i’m happy.

I looked into 3D printing but it appears to cost loads to produce a CAD file for it and the materials used won’t with stand the heat.

Getting injection moulded copies made are also too expensive unless you approach a company to make larger volumes. May be a business opportunity? Now there’s a thought

Thanks for all help and advice

Just as a reminder, if only a part of it is bad you can always fix it. That part was very brittle.

gunhog wrote: Getting injection moulded copies made are also too expensive unless you approach a company to make larger volumes. May be a business opportunity? Now there’s a thought

As pointed out earlier - the cost is outrageous for a "speculation" and what someone would do with a minimum of 1000 KZ 1300 Over-flow tanks, is beyond me.
That's why the "Cleaning Tool' was a big gamble. 2 years to break-even ! (Oh Ye of Little Faith" ) Everyone wants a "Solution" until they find out what the unit price is. Most fail to realize or appreciate that to get the first one of anything made for Proof of Concept can be (usually is) a large outlay of cash that if not recoverable in a reasonable time-frame, is simply not practical nor realistic.

Scotch:

what someone would do with a minimum of 1000 KZ 1300 Over-flow tanks, is beyond me.

Fill it with helium and use for sky diving! hahaha
I'd make a raft and swim around the world