[onelifematt]

Trying to get a video on this post to verify. Will try desktop in a bit.

I have been messing with this 1971 CB450K4 for a few years, off & on now, and this is my first time playing with the starter motor. I have been able to start it with the kicker, but wore myself out recently while trying to get it to idle decently and tune it. Having issues again.

Battery is fresh, polarity is correct there (not labeled wrong), and while jumping the starter cable to the battery, the SM turns clockwise. I would believe it should spin CCW to turn the motor the correct way? The starter clutch spun free, which led me to investigate further. I’ll probably rebuild the starter clutch also. But shouldn’t the SM turn CCW, same direction as the motor?

I have taken this apart a few times now, while double/triple checking alignment marks and assembly lines. Everything seems to go together “one-way”.. scratching my head here. Do I even have the right Starter motor?? Instead of tinkering more & potentially wasting time, I’m considering to purchase a used, properly working one to rebuild.. (Hopefully spinning CCW).. unless this can be fixed?!

Ahh, any further knowledge/advice is highly appreciated. I’ve searched the forum but haven’t come across any similar troubles. Thank you all


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[onelifematt]

Reference photo of my 1971 CB450


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[Rob Axel]

COUNTER clockwise should be correct..
Not sure why or HOW it is spinning clockwise.. the only thing I can think is maybe it is either wired incorrect or the polarity got reversed(don't ask me how they would happen.. I have NO Idea)..

 

[ancientdad]

I was trying to think of an engine from Honda that had the starter motor facing the opposite side, like a 305 might since the alternator is on the right... but that starter motor looks too new-style to be from a 305... right?

 

[drydreamer]

https://images.cmsnl.com/img/partsl...-e-12-starting-motor_big3IMG01171582_162a.gif

Find the stater motor number and compare, you sure that the correct brush is connected to the correct lead?

 

[Simo]

Does it run in the correct direction if you flip the polarity going into it?

 

[onelifematt]

https://images.cmsnl.com/img/partsl...-e-12-starting-motor_big3IMG01171582_162a.gif

Find the stater motor number and compare, you sure that the correct brush is connected to the correct lead?

Thanks for the reminder to simply check the diagrams.. I’m usually pretty good at that. By the looks of things, if their photo is their actual part, I have markings SM-2 on the outer cap/mount which matches. The internal windings are one piece and fit the post hole in what seems to be one way. The hot brush which is wrapped black, is connected to the hot lead coming through the shell. The brush plate seems to fit and line up directly where the hot lead and wrapped brush align. Could it all be so simple? At least I hope I’m learning something..

 

[onelifematt]

Does it run in the correct direction if you flip the polarity going into it?

Confirmed today: still spins clockwise. Post of starter to positive on battery, ground mount/screw tip to negative.

My buddy mentioned that, and I wanted to take another go to verify, with arrows marking the direction I needed it to go, and visually saw it go opposite.. is it worthy.. or scrap? Thanks for the reply and assistance

 

[Rod Fryatt]

I believe there is a planetary reduction gearbox on the end of the armature. Am I right in saying the output from this goes in the oposite direction to the armature? Could it be that this gearbox is not functioning as it should?

 

[onelifematt]

I believe there is a planetary reduction gearbox on the end of the armature. Am I right in saying the output from this goes in the oposite direction to the armature? Could it be that this gearbox is not functioning as it should?

I like where you’re going.. is there a way to change the direction of the output shaft, internally with the planetary gears?


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[ancientdad]

I wondered about that myself, but have never been sure it could be altered... maybe that's what happened at some point in the past. I've never tried it, but I've been fortunate to have never had to work on a starter motor

 

[WintrSol]

Refer to paragraph 5.5 of the service manual. I don't see how the gears can reverse the direction, but, if the brush plate is mounted in the wrong position, it will. There should be index points that force it into the correct position, but those can be easily gotten around.

 

[Rob Axel]

After thinking about it for a while, I would say "yes". IF the connections on the brushes got swapped backwards (by a PO), I don't see any reason as to it not reversing the polarity an direction. I was "fortunate" as when I disassembled mine.. one of the screws on the plate would not back out so I had to leave it while cleaning.. this made it kinda idiot proof when I re assembled.. If I recall, I don't think gettting them mixed up would be difficult...

 

[drydreamer]

It is possible via an epyclic gear set to reverse and play with output ratio compared to input, in the case of a starter motor probaly a gear reduction, ie, armature turns far faster than the starter output shaft.

The important thing is that the output shaft turns the correct way, ie ccw.

Usually stuff can only be assembled one way, or at least marked and mentioned in the manual.

The starter is basically a dc machine ( an bit more complex but hayho ) .

Recheck the correct brush is going to the correct terminal. Have any of the windings been disconnected and re connected in the past, correctly????

 

[drydreamer]

Has the epicyclic gear end been apart, pretty difficult to re assemble incorrectly but easy to not fit parts like the annulus ring gear stop "pin". If the stop pins was left out I would suspect the gear system would just rotate the annulus in its casing when the starter experiences load like a compression, but i dont know exactly how your starter works, gear wise. The kawasaki i have has 2 possible starter motors, a 4 brush one ( thats on the bike ) and a 2 brush type that looks quite like your starter motor.

The clymer manual ( so hated on here ) for this era of bike shows the internal wiring for the motor but not the gear system.

I doubt the battery has "reversed polarity", if so then the diode pack is probably now toast. Only ever come across this phenomena once, but has heard others say it has happened to them/there battery.

 

[Rod Fryatt]

As we are not dealing with permanent magnet motors I think all speculation about battery polarity can be dismissed at the outset.

Seems I am wrong in thinking the reduction gear reverses the rotation. Cannot imagine how it could malfunction to do so though

 

[WintrSol]

The starter gear train is fairly basic:
View attachment 273616

 

[tbpmusic]

As we are not dealing with permanent magnet motors I think all speculation about battery polarity can be dismissed at the outset.

Seems I am wrong in thinking the reduction gear reverses the rotation. Cannot imagine how it could malfunction to do so though

I don't think so - any DC motor can reverse directions when input polarity is reversed.
The direction of rotation of a DC shunt motor can be reversed by changing the polarity of either the armature coil or the field coil, but not both.

 

[Rod Fryatt]

I don't think so - any DC motor can reverse directions when input polarity is reversed.
The direction of rotation of a DC shunt motor can be reversed by changing the polarity of either the armature coil or the field coil, but not both.

Just what I was trying to say. So reversing the polarity of the bike's supply will not alter the starter motor direction.

 

[WintrSol]

Well, if the battery terminals were reversed (not an easy thing to do) the rectifier would quickly go up in smoke, as noted above. If, however, the brush plate is mis-clocked, the motor would still run backwards. There is only a small notch in the motor case, with a corresponding bump in the plate, meant to set the alignment; these are visible in the last photo. The notch is at about the 9:00 position, and the bump in the plate is almost directly above it. It is easy to miss those details, and the plate will still seat well enough if they are not aligned.