i am at the point of looking at speedo/tach for my 72 commando project...ones i see with green ball on face are $500-600 a pair price to rebuild old ones around $250 each...hmmmmmm. so..i have been using repos (you know by who..the Big "E") on my bsa and triumph for several thousand miles trouble free and accurate...so......why not use same brand on project?...I see Big E makes speedo drive and speedo in 1.25/1 and tach in 4:1 ratios same as Smiths green ball originals...I would not be able to use odo reset knob on repo speedo but dremel will shave that off......what say ye? purists roll eyes if'n you want to but send $ to pay for $600 if you care to...oh I dig commando has 19" rear wheel but it is my understanding overall diameter of 100/90x19 avon roadrider is same as 4.00x18 k70-ish rear so wont affect speedo readout
take a look here. i have run them for several years and so have a few bike i help with. great luck rain or shine. they are accurate, well lit at night and the JUNK speedo drive is gone. the only issue is with the speedo being GPS it can loose signal in tunnels and VERY heavy shaded north side of mountains.
there is NO way i would go back to a cable drive set of gauges unless it was a concours resto. if you are having to start from nothing the ones i linked to IMHO is the way to go for a rider. like i stated the POS speedo drive is gone, the leak prone tach drive is gone and the cables are gone also.