Time to test/repair/replace the starter?

[cowboyup3371]

So here it is out of the bike:



It's interesting that I didn't need to hammer it out because it came out extremely easy. And you guys are right, the maintainer wouldn't provide the charge as it didn't see anything.

So I connected the bike battery and it spun. I don't know if there are degrees of "spunness" but I will still take it apart and see how things are inside.

[GateKeeper]

OK, so you say it spun, was this by just attaching leads from the battery to the starter, or did you hook it up as it is in the bike and you hit the starter button ?

It should come out easy, it's really only held by the 2 back bolts, the seal in the front is only there to stop the oil from spurting out.

.

[Redman]

......
..............but I will still take it apart and see how things are inside.

CB,

I think you are going to find like this:




Brushes worn down to where no tension left in the springs. And commutator covered with brush materail burnt in.

And without taking it a apart you can see if it is a Mitsuba or a Denso. Need to know that to get proper brush kit.

.

[Redman]

Brush Holder - DensoType:NewReplacesensoStockers #:ND-LRetail Price: $37.45Your Price: $24.95





Brush Holder - MitsubaType:NewReplaces:MitsubaStockers #:SM-8Retail Price: $37.45Your Price: $24.95

[cowboyup3371]

Thanks folks. I came inside to post that picture, fixed dinner, and got comfortable on here so I haven't torn it apart yet. I can say it's a Nippon Denso though.

Even if I don't have to replace anything inside, is there any basic things that MUST be replaced just because I'm opening it up? I thought I saw an o-ring on the end of the rod; should I replace that anyway?

[cowboyup3371]

So I ran back outside to take this thing apart and much easier than I thought. I'm not sure if I need to remove additional items for checking things but can (circlip pliers are busted so I can't pull that off).

Here are some pictures as well as a short video of what I saw.

End Cap



















And the video



I'm assuming I need new brushes; anything else obvious to anyone?

[GateKeeper]

clean this up with some emery cloth



clean up the rest, and put it back together

brushes seem to be still useable, in my opinion, unless that one that is half of the other is because it's further in, but it seems to be all in good order

.

[TooManyToys]

I'd pull the starter apart before I would be ordering parts. Sometimes it can be something as simple as oily brushes and a dirty commutator. The next step could be brushes, maybe bushings, but the big issue you need to look for is if the magnets have some loose. Those can be fixed too, just look for the thread on here.

Looks like oily brushes and dirty commutator. Years of oil vapor taking it's toll. Use electrical cleaner on all the parts, lightly polish the commutator, and the lack of deep grooving is telling me the brushes may not be worn. Re-clean the commutator after polishing it with 360-400 grit. If you have access to the service manual it should give a limit to the brushes length so you can check them.

[cowboyup3371]

Looks like oily brushes and dirty commutator. Years of oil vapor taking it's toll. Use electrical cleaner on all the parts, lightly polish the commutator, and the lack of deep grooving is telling me the brushes may not be worn. Re-clean the commutator after polishing it with 360-400 grit. If you have access to the service manual it should give a limit to the brushes length so you can check them.

It says the brush length should be a limit of 6mm and the commutator undercut is 0.2mm. I think I understand the brush length is the total length of the piece that's sticking out there. But what does the commutator undercut mean?

[rustybronco]

Commutator undercut is the depth of the cut between two commutator (copper) bars. If you were to turn down the commutator until the insulator and the copper bars were of the same height, you would then need to 'under cut' the mica until it's again below the height of the copper segments.

Under cutting can be done at home by taking a hack saw blade and grinding away the sides of the teeth until the blade will fit between two commutator bars, cutting only the insulator.

[TheCafeKid]

eh...Not to sound like the harbinger of death or anything, but could you bumpstart the bike? Or did you try to turn the motor over by hand?

Im not an electrical whiz by ANY stretch of the imagination, but if it works (spins) outside of the engine, why didnt it spin INSIDE of the engine. My limited understanding of electrical motors (and PLEASE feel free to enlighten me if im completely wrong, which is likely the case) is that they provide nearly instant torque, meaning they dont have to "spin up" to get the most out of em. My point is, if that is true, why would it spin outside, and not inside the motor? If its getting the power it needs outside, would it not be getting it inside as well??? Or am I way way way needing a lesson (and please do teach me...)

[cowboyup3371]

Josh,
I did not bump start it but I successfully turned the motor last night by hand after seeing the starter turned on its own. I am probably going to remove the stator cover tonight to see if something there is busted. There's just a little voice that is telling me something is wrong someplace still.

[tom203]

Josh,
I did not bump start it but I successfully turned the motor last night by hand after seeing the starter turned on its own. I am probably going to remove the stator cover tonight to see if something there is busted. There's just a little voice that is telling me something is wrong someplace still.

Yeah. your starter motor looked OK to me and if it spun up quick out of bike, I think there's something else happenning.

[Steve]

My limited understanding of electrical motors (and PLEASE feel free to enlighten me if im completely wrong, which is likely the case) is that they provide nearly instant torque, meaning they dont have to "spin up" to get the most out of em. ... Or am I way way way needing a lesson (and please do teach me...)

You are (mostly) correct, sir.

Most electric motors do provide maximum torque at zero rpm.
However, in the case of a "slightly less-than-perfect" motor, that maximum torque will be considerably less than it should be.
That would allow it to spin with no load on it, but, when asked to turrn the crank, it falls flat on its proverbial face.

.

[Nessism]

That starter motor looks good inside, particularly the commutator - hardly any wear. One of the brushes doesn't stick out as far as the other. What's up with that? Could it be binding and stuck in the holder or just worn? If the brushes are not overly worn I'd throw that bad boy back together, after cleaning with contact cleaner that is. Anyone know if the bushing needs to be lubed, and if so with what? Common grease?