I bought a stolen recovered 2003 America (carb model) and the speedo glass had been smashed so I looked around for a good used speedo but found nothing really any good under £100. I worked out that the glass is domed (convex) and after a little web searching, I found a domed speedometer/tachometer glass from a Triumph sports car (keeping it Triumph of course!) is the perfect fit. The glass is for a 5-inch Smiths/Jaeger speedo/tacho and is actually 116.5mm in diameter with a perfect dome to it (and it is the correct 1.7mm thickness), to fit over the America/Speedmaster needle etc. It cost me £11 delivered from an excellent online seller who sells everything old and automotive at some of the best prices I could find, for relays, electrical, all sorts of stuff. https://www.autoelectricalspares.co....uge-1565-p.asp (I have no connection to the company!) After prying off the stainless steel ring with a small blunt screwdriver: go slowly all the way around, a bit at a time, you may need to go around it a few times. You won't need to bend the lip up by 90 degrees, just enough to slip the ring over the plastic body of the speedo. I trial-fitted the glass inside the rubber ring that fits deep into the stainless steel ring and it seemed a good fit but pretty tight. I rubbed about 0.5mm off the diameter of the glass with some coarse (40 grit) then finer (120grit) sandpaper, getting it down to 116mm. I think it would have gone in OK without rubbing down though. I put some Vaseline on the rubber ring to help it slide into the steel ring (don't use an adhesive or sealant as they give off vapour which clouds the glass and can stain the dial as well) and assembled it all and pressed the lot together using a vice and an old domed camping gas lamp top which pressed on the steel ring but did not touch the domed glass. I clamped it as tight as I dared, against the speedo drive gearbox on the back, distorting the plastic case a bit but not affecting the drive/workings and not cracking the plastic case. After leaving it clamped for a bit, and while still clamped, I used a very light hammer and punch to peen over the steel ring in a few places and then took it out of the vice and turned over the edge of the steel ring all the way round with duckbill pliers, using a strip of aluminium on the front face side of the pliers, to protect the visible finish. After a lot of patient crimping, I got a very even crimp all the way round and I have to say it looks almost factory! As some savage had smashed the glass and chipped some of the off-white paint/print finish on the speedo dial, I mixed some household white paint with a few drops of black but was not able to get exactly the right shade for some little touch-ups but it looks pretty good. The same savage (I presume) had also broken the needle stop peg that sits at 0 mph so I glued a short length of a WD40 straw to the stub of the stop that was left, after opening up the end of the straw with a small scriber tip, and dabbed some blackboard paint on it (as the WD40 straw is red). I'll post up a picture of the finished article when I can. A rather long boring account but I am quite proud of the repair and it could save you £150-300 - the cost of a new speedo... A note: if your glass has been smashed, be sure remove the whole 'guts' of the speedo from the inner white plastic case (two screws on the back) and get all the glass bits out of the mechanism with a fine brush and some gentle compressed air, the bits get everywhere inside and will stop the speedo working if not removed.
Thanks, I forgot to say that I did NOT 'adjust' the mileage either... I remember when working as a car mechanic for a rather disreputable dealer many years ago, I was guilty of adjusting mileages. One car had a slip of paper inside the speedo case that said 'oh no, not again'! It had already been 'clocked'...!
