you can wind the miles off with a drill, but you'll have to hold it on there. remove everything from the back of the speedo. this includes totally stripping down the clocks btw. take off the bit that the cable attaches to. this cunningly stops miles coming off when you reverse. you then should see teh cogs that count. by getting a pinion from an old RC car on your drill you should be able to wind them off. just remember to undo the face else the neddle might snap. I havent' actually tried this yet, but I'm pretty sure that's how it's done. I have a broken apart clock so if anyone wants me to I'll try it.
either that or remove the pin and set whatever miles you want on the clock.
