Mitsuba 4 brush starter brush replacement.

[Redman]

Here are some pics of when I took apart the starter to inspect brushes. (and to see if NipponDenso or if Mitsubsa 2 brush or 4 brush).

Can see the brushes are kinda short, down close to the wire connections.

I see the wires from the ring that go into the motor (not pictured), but not seeing how to disconenct/reconect the wiring. At the ring? At the terminal and case ground somewhere? I did pull the ring out a little bit to look around.

Here are some pics showing some other things, and what I did.

SHowing how much brush dust and chunks was inside there. Was also lots of brush dust packed in on the armature (rotor) and on the stator, not much clearance inbetween.
Showing how short the brushes are.


Showing commutator.



Commutator after I touched it up with 100 then 180 grit sandpaper. (Thought I had some emmory paper but couldnt find it right away.)


Ah, getting it back together was right at about the limit of my patients and manual dexterity. This little trick helped quite a lot: Took some little pieces of cable ties and used them to hold back the springs, then could put the brushes in place and they would stay back so could get rotor back in place. Some of the brushes I turned around because they were wore down right close to the wire attatcments and was more remaining bush length on other side of the wire (dont know if this good idea or not).


So I got it back together, and will reinstall tommorow and see if any better.

And I now know the brushes are short and need to be replaced. I know can get a set of brushes, or can get a kit with brushes and ring kit. But not seeing how to disconnect and reconnect the new ones.

Reason I am doing this is that sometimes the bike turns over fairly slow. Most often seems okay. Battery and charging are okay.

.

[J L McCoy]

Redman,
I'm doing a brush kit and Commutator clean up on my GS850. I ordered the brush plate kit SM8 from (http://www.stockers.com/NEWSS5.htm). Do the plate kit unless you can spot weld not solder the brush wires yourself.

Next,
I chucked the armature in a drill press.
Set a fine file and a block of wood on the table, use the wood to support the file at 90deg. to the table and parallel to the commutator.
Adj. the table height so the file leaves 2mm of space from the commutator wire connections.
Run the press at slow speed and file flat, you should be ok.
Smooth the surface with 600 sand paper.
Clean out the groves between the commutator with a piece of fine sand paper folded in half so no metal bridges the contacts.
Ohm test, pm if you don't know how.
Good luck

[Clone]

The commuter on your starter is not flat, that will cause arcing and it will carbon up quickly forcing you to tear it apart again. Once the the brushes are down close to the wires you should really get new brushes as cleaning up a burned commuter is not fun.

[J L McCoy]

Flat as in holding the file steady resting against a block with armature turning, move block and file against the turning commutator. stop when it looks like this.

[Redman]

J L , & Clone,

Thanks for sharing your wisdom and experience.

I have been to Stockers (and other) web site and have seen the replacement brushes and the ring/brush kit. And now thinking the ring/brush kit will be a better option (especailly now that I see I have the 4 brush unit).

I see the two wires leaving the ring, and go into the starter body/housing. WHat I could not determine is how the connection was made to the positive terminal and (I assume) the case ground. Could only pull the ring out a little bit, and when I looked in thru other end of the case could not really see where/how the connections were made.

THis attempt at dissassembly (1st time I ever had a starter out, and 1st time I have ever had a starter apart) was mostly just exploration to see if NipponDenso or Mitsuba 2 or 4 brush. NOw that I know that, I can get a ring/brush kit on order. BUt while I had it apart I just touched up the commutatator. I know the commutatior isnt flat, but neither are my brushes at this time, contour of commutator somewhat matches the brushes at this time, ... and this is just a temperary situation, till I get the ring/brush replacement. Hopefully doesnt damage anything in the mean time. Maybe I should concider getting the ring/brush kit locally so dont have to wait for shipping.

And I did clean out between the commutator bars. And next time I will get finer grit sandpaper, and make it flater to match the new brushes.

So my big question is:
WHen replacing the ring/brush kit: How to disconnect and reconnect the wiring from the ring/brush to the positive terminal and case ground?
?
?

[Grandpa]

The commuter on your starter is not flat, that will cause arcing and it will carbon up quickly forcing you to tear it apart again. Once the the brushes are down close to the wires you should really get new brushes as cleaning up a burned commuter is not fun.

I had a 1982 GS850G, back in the early 90's, that developed a starter problem. I opened up the starter, replaced the four brushes, and had to tear it apart again, as you mentioned. The commutator was not flat.

So I discarded the starter, bought a used starter from a graveyard. This "new" starter was for an earlier 850, with just 2 brushes. It fit the 82 GS850 perfectly, with no mods. It worked perfectly for several years.

It seems as if the 2-brush starter is more durable than the 4-brush.

On the other hand, in my 1984 GK (now TheCafeKid's) with 132,000 miles, I didn't replace the starter at all, and it worked great until I sold it to him.

[Planecrazy]

On the other hand, in my 1984 GK (now TheCafeKid's) with 132,000 miles, I didn't replace the starter at all, and it worked great until I sold it to him.

Now you've done it, Nick! You HAD to go and tempt Murphy, didn't you? You DO realize that within the next few days that starter is going to eat itself, don't you?

Dave,

When you order the brush kit and see the new parts you should be able to figure out how to take apart the old ones. I did exactly the same thiing to my "G" starter two years ago when it suffered the same symptoms as yours, and the "reversed" brushes lasted less than a week afterward. It is only fair to add that I was unaware that I should sand down the communtator so it was flat and that probably contributed to the quick failure of the reversed brushes.

After getting the replacement kit the starter has worked well, but still that's without having flattened the commutator contacts - hopefully they were in better shape than yours - it's been two years and I honestly don't remember. However, I DO remember discovering that there is an inherent flaw in the design of the springs which causes the brushes to lose contact with the commutator and start to disintegrate well before they're worn completely down. When I rebuilt my starter I went out of my way to fix the flawed design (and I even posted about it - I'll try to find that thread) so the new brushes will work more reliably for longer.

Regards,

[Planecrazy]

Dave,

I did a search but could not find the thread I thought I posted on the brush rebuild ... however I DID find a post I made referring to the flawed spring design and how to correct it. If you try this repair be VERY careful because the springs are brittle and will crack/snap easily if you are too aggressive while trying to modify them.

Here is the post I made:

"On my four brush starter I discovered that there is a design flaw in the way the brush springs are shaped (right where they contact the back of the brushes) that causes them to "catch" on the brush guides and the result is that the brushes are no longer being pressed against the armature properly. On my bike it had been that way so long that the brushes had disintegrated... If yours still look good you can try what I did:

take a needle-nose pliers and very carefully twist the spring ends around so that the edge no longer "catches" on the brush guides. On my starter it was so obvious that the guides actually had grooves ground into them -- if this is your problem you'll know exactly what I mean. By "rolling" the ends back you'll notice that the springs can travel much farther into the guides, and provide proper pressure to the brushes.

The reason your starter is spinning so slowly is that one or more brushes is failing to make contact, and the other brushes are are being forced to do more work (thus the heating up of your wires, etc.).

Hope this is helpful!"

Regards,

[Grandpa]

Now you've done it, Nick! You HAD to go and tempt Murphy, didn't you? You DO realize that within the next few days that starter is going to eat itself, don't you?
Regards,

Planecrazy, not to worry. I gave TheCafeKid an extra two-brush starter, off an old 850G I used to have.

The reason I never needed for the GK is simple: I had it!

[Redman]

Nick & PC Steve,

Thanks Guys.


About the connections:
Thanks for the clue Steve.
I also took a clue from the service manaul I have for '86 Honda Shadow 500. It shows a 4 brush starter (Zuki manaul shows 2 brush) and the internals look the same as my starter, only difference is the end cap has different bolt pattern.


I notice a couple things:
- the two wires going in to the motor case are both the + leads for 2 brushes, and then the other two brushes must be grounded to the case.
- And those two wires are connected to the positive terminal thru that clip. So somehow that clip must be insultated from the case. And I gather that the ring/brush kit comes with that clip with brushes attatched.

I did get the starter back in. And it does turn over much better, I would guess just from cleaning out the dust and touching up the commutator. But one time (out of about 6) it did falter a bit before turning like it should, so that hasnt changed. But when it does go, it goes better.

So Yep, I will get a ring/brush kit on order.
AH, I see that spring clip connected to two brushes, and 2 more brushes connected to the ring.


And I will look into the situation with the springs catching on the brush quide (maybe why it sometimes falters). Maybe that is more critical after the brushes get worn way down.

Oh, If any one is interested: Can get starter out of 1100G without taking off carbs, nor removing cam chain tensioner (dispite what Clymer book says), just like Steve Plane Carzy told me.

.

[mixongw]

Some time ago I replaced the brush plate in my starter. The commutator was a little rough so I managed to clean it up with a drill press and a file. It looked good so I put it all back together. It worked great for about 10K miles but started acting up again. I took it apart and found the brushes had turned to dust! They were totally shot. I just got off the phone with stockers.com where I ordered a rebuilt starter for $144.00. That is what I should have done the first time. I was trying to save a buck and get by with just a brush plate for $25.00.

My starter now spins the motor faster than ever!

[Planecrazy]

Some time ago I replaced the brush plate in my starter. The commutator was a little rough so I managed to clean it up with a drill press and a file. It looked good so I put it all back together. It worked great for about 10K miles but started acting up again. I took it apart and found the brushes had turned to dust! They were totally shot. I just got off the phone with stockers.com where I ordered a rebuilt starter for $144.00. That is what I should have done the first time. I was trying to save a buck and get by with just a brush plate for $25.00.

My starter now spins the motor faster than ever!

With all due respect, that means that with the $25 brush set and an hour or so of "tinkering" every ten thousand miles you could get more than 50,000 miles out of your own handiwork for the same money. it's not that I have anything at all against buying a quality rebuilt starter (and that's a decent price for one) ... it's just that I think you'd get better at the rebuild with each "exercise" and probably get more miles with each subsequent job, plus there's the satisfaction of having "done it yourself."

...just saying.

Regards,

[chiphead]

Nick & PC Steve,


Oh, If any one is interested: Can get starter out of 1100G without taking off carbs, nor removing cam chain tensioner (dispite what Clymer book says), just like Steve Plane Carzy told me.

.

Excellent. I was wondering about that. My starter began giving me grief this past weekend. Thanks.

[Planecrazy]

Excellent. I was wondering about that. My starter began giving me grief this past weekend. Thanks.

Yes - no big deal. Once the starter cover is off and the bolts disconnected it's just a matter of a few careful angles and it'll come out without any major problem!

Regards,

[lecroy]

Talk about timing. I just killed another starter motor. Standard 2 brush ND. Really did a number on this one and there is no repair. Stator contacts were turned to balls of copper.

There is a lower limit to how much material you can remove from the stator contacts. I put mine in a lathe and use some 600 on a block. Drill press is a good idea too. I use a dull model knife to clean between the contacts. Finish up with break clean to remove any greese from my fingers. Oil/greese will not conduct and any on the contacts and brushes will end their life early.

Anyway, I'm curious if you break them in or not? After I service them I will run them out in the open for a while with a lower voltage and with no load to get the brushes to seat back into place.