Mystery Starter Motor

[Seadog]

First, let me admit that I am not an electrician or even close to being one. My knowledge is limited and also my familiarity with motor terms. Bear with me, please.

I have 2 starter motors that I had hoped to repair. One is the standard Denso. No mystery. Unfortunately it's pretty far gone, having sat in the dirt for an unknown length of time. The two bearings are rusty.

The second motor is a mystery to me. It's has no markings on the exterior of any kind - no plate or markings on the commutator cover. Also, the armature/rotor is smooth, with no groves. Dismantling the motor was easy - much too easy. It was clear that it had been opened sometime before. Inside, the motor is in very good condition. No rust or furry stuff. Shiny copper. The brushes looked new, as did the springs. Here's the problem:

Before I opened up the motor, the armature was loose in the case. It would shift back and forth inside. When I opened the motor up, there didn't appear to be spacers for the armature at the front, as I've seen in Denso motors. There was one beaten slightly conical spacer at the rear. Consequently, the front of the armature was making contact with the inside planetary gear housing, making score marks on the housing itself and wearing the copper wires of the armature. It seemed to me that there should be spacers at the front to stop that. On closer inspection of the armature shaft, I could see a spacer (it turned out to be 2) low on the shaft. I pulled them out with a dental tool. Both are conical, but I cannot determine how they are supposed to work. They were obviously installed incorrectly.

Does anyone have information on this type of motor, it's parts and how it's assembled? See photos, below.

The mystery armature on the left, Denso armature on right:


Armature windings in contact with gear housing - space needed here:


Subassembly. Conical washers at front and rear:

[G-Man]

Seadog

I have no more experience / knowledge than you but I do have some spare starters. Let me check them out.

Do both of your starters appear to be the same outside dimensions? i.e. would the mistery starter fit a Honda engine?

G

First, let me admit that I am not an electrician or even close to being one. My knowledge is limited and also my familiarity with motor terms. Bear with me, please.

I have 2 starter motors that I had hoped to repair. One is the standard Denso. No mystery. Unfortunately it's pretty far gone, having sat in the dirt for an unknown length of time. The two bearings are rusty.

The second motor is a mystery to me. It's has no markings on the exterior of any kind - no plate or markings on the commutator cover. Also, the armature/rotor is smooth, with no groves. Dismantling the motor was easy - much too easy. It was clear that it had been opened sometime before. Inside, the motor is in very good condition. No rust or furry stuff. Shiny copper. The brushes looked new, as did the springs. Here's the problem:

Before I opened up the motor, the armature was loose in the case. It would shift back and forth inside. When I opened the motor up, there didn't appear to be spacers for the armature at the front, as I've seen in Denso motors. There was one beaten slightly conical spacer at the rear. Consequently, the front of the armature was making contact with the inside planetary gear housing, making score marks on the housing itself and wearing the copper wires of the armature. It seemed to me that there should be spacers at the front to stop that. On closer inspection of the armature shaft, I could see a spacer (it turned out to be 2) low on the shaft. I pulled them out with a dental tool. Both are conical, but I cannot determine how they are supposed to work. They were obviously installed incorrectly.

Does anyone have information on this type of motor, it's parts and how it's assembled? See photos, below.

The mystery armature on the left, Denso armature on right:


Armature windings in contact with gear housing - space needed here:


Subassembly. Conical washers at front and rear:

[Seadog]

Thanks, G. The starter was mounted on my '62 engine, so it fit, but whether it was from another Honda engine is unknown. It would be interesting to see if you have a similar motor in your parts cache.

I'll play with the spacers today to find if there's some combination of positioning that works. Last evening, I tried facing the two conical washers with their wide ends facing each other. It gave the rotor the spacing it needed, but it wasn't stable and I don't know if the spacing was right. Perhaps there needs to be a flat spacer between them. I just don't know. Unfortunately, I do not have a local source for any kind of thin spacers.

I haven't given up just yet, but I will not be surprised if I have to in the end.

Seadog

I have no more experience / knowledge than you but I do have some spare starters. Let me check them out.

Do both of your starters appear to be the same outside dimensions? i.e. would the mistery starter fit a Honda engine?

G

[Seadog]

Well, I’ve played with the shims in every configuration possible and have come to the conclusion that some are missing. Upon reassembly, the armature is still a bit sloppy in the case. Upon the last assembly I tested the motor and it runs. I’m cleaning it up now and will paint it and put it back into service. The only marks I’ve found on it are below. I’m still hoping someone will be able to provide some more information about the shims. I’ll post the question elsewhere as well.

[DJM]

I'm pretty sure that Honda used starters from two different manufacturers on the C/CB series engines.

The common one is the Nippon Denso which carries the oval ID plate on the front, can't remember the other make, could be Kokosun.

Obviously they need to be dimensional identical as either can be used on the engine but I don't think any of the internal parts are interchangeable. Sounds like you have one of the 'other' ones.

[Seadog]

Thanks for the info. There’s also a Denso without the oval plate. The trademark is on the commutator cover.

I did find a few of these mystery starter motors on ebay. Most looked better than mine and there were a couple that were not working for $44. I’m not buying $44 shims, assuming they have them, so mine will stay as it is for as long as it works.