First thing to do is check the wire connectors between your reg/rec (or regulator and rectifier if they are separate and stator and main fuse box and battery... Separate all the connectors, clean and dab with dielectic grease. If that doesn't fix the problem, buy a small hydrometer (looks like an eyedropper) at an autoparts store and check each cell in the battery for sulfation. If you find ANY cell that isn't 100 percent OK, buy a new battery. Check the battery cables as well to ensure they are clean and tight. If these things don't do the trick... move on...
There are different types of 650 stator... not sure I understand the differences but if there are three AC wires coming off your stator, you can check AC voltages when the bike is running. Disconnect the plug that connects the stator to the reg/rec or regulator while the bike is running. With a multimeter, check AC voltage (meter must be in AC scale) in every possible combination of the three wires. You should get a certain amount of AC... if one of the checks yields nothing, the stator is bad (if there are no broken wires). The voltage level at idle should be about 50 VAC I would get any way you check it and quite a bit higher when you rev the engine to 4K rpm. Check a manual to get the true voltage specs. Anyway, if the stator checks OK, then measure DC voltages at your battery. You should get about 12.5 VDC at idle and 14.5 VDC at 4k rpm. If you get significantly different values, the regulator is suspect or reg/rec is suspect (depend on what type set up is on your bike).
Post edited by: wiredgeorge, at: 2007/07/26 09:27
