Charging system testing- weak starter? just clicking? Is it the battery?

[Thumper]

Does your bike just "click" when you press the starter button? Or does the starter motor weakly turn the engine over and it fails to fire up?

Maybe you wonder if your charging system is not maintaining the battery? Do you need a voltage regulator? Do you need a new stator??

Here are a few things to test:

If this is a used bike you are trying to get running, check the valve clearance first.
Here are instructions to adjust valves. If you haven't adjusted the valves, then do this first ANYWAY. Covered elsewhere...The process is identical for any of these 4 stroke engines, but clearance on pushrod engines should be 0.003-0.005" exhaust, 0.002-0.003" intake:
https://www.chinariders.net/showpost...4&postcount=21

If the starter turns the engine rapidly, but it just isn't firing up, it could be spark or gas issue, but if it ran OK before and the starter just isn't cranking it strongly, you may have a weak charging system resulting in low battery charge, dead or bad battery, or you just need a charge.

If you don't already have one, BUY A MULTIMETER. You NEED one to test your battery, and to test your charging system.

If you can jump it and it turns rapidly and starts, GREAT. While it is running, USE THE MULTIMETER (set to DC voltage) to test the charging system: Connect the multimeter to the battery terminals-red to red (pos) and black to black (Neg/ground) and you should see MORE than 14 volts pushing onto the battery at ~1500-1700rpm.

If it started with a jump, and the charging system checks out, then charge the battery. A floating battery maintainer/charger costs about $35.

RESTING BATTERY TEST (key turned OFF): AFTER charging, what is the resting battery voltage? It should be at least close to 13V for a healthy battery. If it is less, disconnect the ground and test it again. Did the voltage go up? If so, your bike is constantly draining the battery (short somewhere? bad switch?).

A BAD battery (grounding out inside) can suck the voltage and prevent starting. It won't charge if this is the case, and will overheat your charger (charger should show the ground fault). This is actually pretty rare unless you bought a barn find or the bike hasn't been run, but left out and neglected for a year or two. If the valves are adjusted, and the bike has been running with a good spark plug and the charging system is good, even a WEAK BATTERY can usually start the bike. Batteries do eventually fail of course. If it can't charge to and hold a charge of ~12.5V overnight, replace it.

As mentioned above, if you can jump start the bike and it starts easily, then charge the battery and do the resting battery test above.

If the charging system is not pushing 14V or more into the battery at 1500-1700rpm, then your charging system is not up to snuff. It could be the rectifier/regulator, or it could be a weak stator. If the resting battery voltage test is the same with/without the negative ground connected but the charging system isn't pushing 14+ volts when running, then you will need to troubleshoot the charging system.