OK the first thing that would really help is to know exactly what it is.Is it possible to take a picture and upload it? If not does it have any marking stickers on it to help.From what you saying it obversely has a decompresser value on it so it must be at least from the 1970's onwards.Does it have a metal carby or a plastic one? Picture would be fantastic if that is possible.I'm sure that we can work it out.
