The rear tyre on the “spare” DT250 was flat, so I went to pump it up, but nada. I removed the old valve and tried to screw in a new one, but there was an obstruction that wouldn’t allow me to screw it in. Turns out a previous owner had screwed another valve deep into the stem, underneath the other one! I’d never seen that before but my valve remover couldn’t reack it. I made another one using a 5mm screw with the thread ground off and aslot cut into it. I still couldn’t get it out so wound it further into the stem then installed a valve and was able to pump it up. The front tyre was badly cracked so I just put 20 psi into it and called it good. In over 50 years of mucking around with old bikes I’ve never seen 2 valves in one valve stem. Luckily I’m taking it to a swap meet next weekend so won’t have to worry about it.