There are no good replica speedos that I'm aware of.. (other than the Smiths electronic version which isn't really suitable for an M20)..
Unless things have changed, the Indian 'replicas' are a different ratio, have different cable attachment fittings and are conical in shape (that's why they never show the back in the pictures)..
If you are considering the one you have mentioned ask for more pictures and more information before buying to establish that it is actually a replica in a meaningful sense...
You can buy replica ammeters from most British bike shops or probably better, e bay. That way you get to have a look at the face style...
Again as far as I am aware there is no totally accurate repro of the wartime ammeter, but at least in that case there are some reasonably good ones...Ian
I believe I have the CZU27 which I could only find that it was up to 39 and 45 onwards. Never saw info on the DVD docs of what was 39 to 45 but there is so much info I could have missed it. Then again I'm satisfied it's an M20 since I have so many other items that appear to be post war around 45.
Why not buy an original speedo, there's nothing else that will work.
Carefull looking at jumbles etc. will find you one, I found one for 100 pounds last month, even if it has a trip odometer, or the wrong face, the right speedo face can be bought original or repro, for around 20-30 pounds.
Any extra holes in the housing can be welded, and you will have something that makes your bike more valuable.
My 2 cents! (I would never pay 300+ pounds for one on Ebay)
Have enough for my bikes now, so not looking anymore, in the old days you could buy them new in the box, but guess those days are over.
It takes the original cable,
It has a closed box (Bit higher than the original)
It is cheap and it works fine,
And it has an internal illumination you can use.
BUT (!!!)
The ratio is 1:1 instead of 1:2, so you would get the reading in Km/h,
More or less, (And not Ml/h)
The mounting screws are aliened with the cable port,
So it is a bit tricky to install with the original mounting bracket.
I use a very similar type (With a trip meter) and keep the original at home,
Because I do not have a shed, and I do not want to be worried of
Someone picking it up when I'm away..
Brian theres a chap in birmingham that is selling the correct revamped smiths speedo for £250
carnt find his contact details as yet but a mate is coming over this afternoon and he knows him . If your interested let me know and ill sort it this end regards Gary