Motorcycle Repair: Honda cg125 timing, honda cg125, little hammer

Question
Hi, I am in the process of doing this little bike up. I have cleaned the carbs, replaced plug oil etc. Can you adjust/check timing on this cdi version. When idling its fine but rev the engine makes a noise. Its only done 10K miles and oil was free from metal/debris when changed. I am not sure how quiet these engines are

Answer
Ashley, there's no way to adjust the ignition timing so if it's running the timing is probably okay.  It depends on what type of noise it's making.  If it's a knocking noise like a little hammer is tapping inside the crankcase, that's bad.  Take a long screw driver and hold the handle to your ear and put the blade on various parts of the engine.  It will act just like a stethoscope and you can pinpoint where the noise is coming from.  If the noise is loudest from the cylinders, it's a piston.  If it's in the top of the cylinderhead, it's a tappet or cam bearing.  If it's loudest on the crankcase, it's could be a rod or main bearing. If all you hear are whirring noises, that's normal.

Regards
Rich