Starter Rebuild

So my starter quit working. It went from giving half a try to just chattering and not trying at all. I’ve been needing to rebuild it anyways so here goes.

Starter and rebuild kit
Starter and rebuild kit

I found the rebuild kit on Amazon, it’s really as easy as googling CB700 starter rebuild kit and clicking on the first link to come up.

Brushes, before
Well there’s your problem lady.

No wonder it was failing. It’s not supposed to be that grimy, but nothing a little electric degreaser and a toothbrush can’t fix.

 

Remove brushes
Remove brushes

First step is to remove the brush holder, to do this you have to remove the brushes. To remove the brushes you have to slide the brush holder up above the commutator so they can pop out of their holders. It’s hard to see with all of this grime but two of the brushes are connected underneath the brush holder and you don’t have a whole lot of slack to play with. Just be gentle and don’t break anything.

 

Brush holder removed
Brush holder removed

Brush holder removed. You can see the two brushes that were connected underneath the brush holder. The armature should slide out now.

 

Armature removed from case
Armature removed from case

The armature removed from the case, neither look all that bad. The service manual warns against using sandpaper or emery to clean anything. I found all I needed was some electric degreaser, a toothbrush, and a clean rag.

 

Test continuity between commutator pairs
Test continuity between commutator pairs

Test continuity between the commutator pairs. There should be 0 resistance.

 

Test continuity between commutator and armature shaft
Test continuity between commutator and armature shaft

Also test continuity between the commutator and armature shaft. There should be infinite resistance, or a 1 on my meter. Go ahead and test all of the bars. If any have continuity the armature may need to be replaced.

 

Clean the starter case
Clean the starter case

Cleaning the starter case, a toothpick will help get into all of the corners.

 

Test continuity between terminal and brush
Test continuity between terminal and brush

Drop the armature back into the case and test continuity between the terminal and the brushes.

 

New brushes, new brush holder
New brushes, new brush holder

Next install the new brush holder. There are channels for the bottom brushes, and tabs to help you align the brush holder with the case. The problem is the whole thing is magnetic, the brushes are spring loaded, and all four need to be held back in order to slide the holder down over the armature. I wish I could tell you I found some trick that makes this easy to do, but basically you need 10 fingers, 8 tentacles, several 4 letter words, and it helps if you hold your tongue just right. 5 to 35 minutes later you should have all the brushes in place and the brush holder installed.
(A trick has been found! See UPDATE at the end of this post.)

 

Rear bracket
Rear bracket

If you look closely, on the brush holder you will notice a tab sticking up. On the rear cap you will notice a slot, and you guessed it, the tab goes into the slot.

 

Rear Cap - index marks
Rear Cap – index marks

There is an index mark on the case and on the rear cap. Once everything comes together those should line up. If they don’t, then you either missed the tab and the slot, or the brush holder isn’t oriented properly in the case.

 

Planetary gears
Planetary gears

Now flip the starter over, being careful not to let the rear cap fall off, and drop the shims, shield, and planetary gear set back in. A little dab of bearing grease is good here.

 

Starter motor installed
Starter motor installed

The front cover will have two tabs that go into the planetary gears and a key to line it up with the case. Pretty self explanatory. After that just, slide all of the gears back on, install the new O-ring, and slap it back into the engine.


UPDATE::
Solution to the brush holder install. Thanks to E.H. Cavignac (NghthawkLvr) you no longer require 10 fingers, 8 tentacles, several 4 letter words, and holding your tongue just right to install the brush holders! Check out his solution in the photo below:

10 fingers, 8 tentacles, several 4 letter words, and holding your tongue just right no longer required!
10 fingers, 8 tentacles, several 4 letter words, and holding your tongue just right no longer required!

Suggestions and solutions are why it pays off to join an online group supporting your hobby.
Nighthawk Lovers – Google Group

One thought on “Starter Rebuild”

  1. Hi mate,

    I have just finished the same starter rebuild with a kit I bought on ebay, there is something very satisfying breathing life into this knackered starter, I did find that if I tightened it to much it wouldn’t turn but a little adjustment and it works perfectly, This is my 2nd cb700sc, I love them best bike I ever had and its the same colour as yours, the nicest in my opinion. Keep up the site its wonderful to see someone as passionate about this bike as I am.

    all the best

    Marc , Dublin, Ireland

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