Charging problem: CB750 K 1977

[v. hayes]

Hello,
  I just got my first bike a couple of months ago, but haven't been able to ride it because the battery won't charge.  I replaced the battery and got new rect. / regulator, but it is still not charging. Looking at the manual, it seems the next thing to check would be the alternator.  I tested the resistance of the field coil, and got 7.2 ohms. The 3 yellow wires from the stator read 0.9 ohms.  The manual says the stator reading should be .2 ohms.  Also, the AC output is .079.  Does it make sense to replace the stator?  If so, can anyone suggest a place to get one online?
  Any advice would be helpful.
Thanks,
Tony

[Re-run]

So you have done all the testing specified in the honda manual? Have you made sure all the contact points are clean? When you replaced the reg/rec, was it an all in one unit or stock honda parts?
If it was stock, the regulator is mechanical and may need to be set to work right.
If all in one, contact the company to find out how to test it to make sure it is not a bad unit.
If all the tests still fail, then try contacting electrosport or rmstator.com and see about a replacement or getting yours rebuilt.

Have you taken a voltage reading at the battery just so you have a reference point? Hook up the meter and rev to 3000 - 4000 and get the reading. Keep it so you know if you have improvements after trying things.

[v. hayes]

Thanks for the advice.  I did the testing in the manual; I haven't cleaned the contact points. Sorry if this is a stupid question, but how do I go about cleaning the contact points?
  I've check the wires leading from the alternator to the rect / reg for continuity, and I've found no breaks. The rect. / reg is not stock it's an all in one; I'll check with the seller to see about testing it. I have checked the battery for voltage, while revving the engine the voltage doesn't exceed 12.50.  

 

[LukeM]

They're is a tool called a points file. It has a mild cross hatch pattern, and is not very abrasive. There was also a tool called a burnisher, that put a square edge and a smooth finish on the points. Check your local auto parts store and see if they have these tools. Don't use emery cloth or sandpaper on points: that elk leave a residue that will eventually kill the points.

Hope this helps.
Luke M

[Re-run]

A points file is good, you can also use small diamond files, I would just run a piece of paper between the points to get any grit off. I used to do that and it seemed to work ok.
Sandpaper can be used but you must clean the points afterwards or you get the bad things luke said. AND it is not as accurate.