I recently bought a 72 honda cb750. It seems that when i drive with my headlight on it drains the battery until finally the bike dies. Is this a common problem, or am i looking at getting a battery charger or a new alternator.
No it's not a common problem from my perspective. Some of the cb's would have a problem with oil seals leaking into the alternator cover - that might give you a problem. But this problem sounds more related to a faulty regulator or a bad battery. My manual gives the following reasons for No charging:
- Broken wire or short, loose connection
- Defective coil due to short, grounding, open circuit
- Defective silicon diode
- Broken or shorted lead wire at regulator
- Regulator voltage at no load is too low
If the problem is insufficient charging then there is a whole section about generator problems, regulator and battery type problems. Your best bet is to get a manual (you can find them online at the SOHC web site and go through Chapter 8 on the charging system. In that section are a host of test procedures that should help you figure out the problem.
I just got done reading thru a ignition thread that talked about circuit load using various ignition setups. It seems that some folks try to run halogen lights with Dyna coils and Dyna S setups. Apparently, the honda charging cannot keep up to keep the battery charged up. This could be something in regards to your problem. Go to the General section of this form and read the Dyna S thread. At the very end of the thread - Geeto will have a link to SOHC form by HondaMan. Link to that form and read through it.
The battery in there was dead gone done, i put a new one in there and it was good to go. Its a regular head light (cheapy). I may get a tri light later on. As for my light draining my battery i'm just going to trace my headlight wiring and hope its just a grounding problem
Have you checked your charging system? I mean have you put a voltmeter on the battery with the bike running and a fully charged battery? If not, then you are just wasting time om speculating what kind of problem you have.