Number one son is showing some interest in bikes. I managed to find him an 80's RG125 non-runner a while ago for the right sort of money[1]. As I are mostly being absent father following my day in court with his mother, I have to try and help him remotely. I did try to start the bike when we first got it, but without any luck. Seems to be plenty of fuel + sparks, but very little compression. Bloke I got the bike from thought that it may have been fitted with the wrong size piston and/or rings. Son has got the head and barrel off without any drama so far.. Piston is v. shiny and looks like it has never run. There's also a strange looking cover on the barrel, looks like it's for some kind of powervalve, but there's nothing inside. Googling reveals they may never have been fitted, and it -may- be 12bhp?[2] Has anyone got an RG125 manual please (or piston size, bore, ring gap data?). Is there anything else (reed valves[2]) that can cause low compression? IS there an easy way to check, without accurate measuring instruments, the sizes etc? Any other thoughts? [1]Free [2]Which would be a good thing, as he 3as no license yet [3]Reed valves being a mystery to me, being a 4-stroke person TIA
