1992 Yamaha SR125 Starting motor brushes

[Emma]

Hi there, 

I got a 92 SR 125 at the start of the year. It's been a project and a half. 

 

I had it on the road for about a month before it wouldn't start. I've narrowed the issue down to the starting motor, I reckon it just needs a good clean and possibly new brushes. 

However, I can't find brushes for my year of bike and don't want to get one's that aren't compatible. I was hoping someone could inform me of other years from the model that would be compatible, or other models that would be compatible.

 

Any help would be greatly appreciated as I just keep seeming to go in circles online without getting any new information.

[Hairsy]

I'd suggest removing the starter motor (if you haven't done already) and then look for part numbers / manufacturer details for the starter motor itself (rather than the bike it's fitted to). You can then search for the brushes for that model of starter.

 

You may also find that with a little bit of every fine emery paper, you can clean up the existing brushes. This, combined with some contact cleaner, might kick the starter back into life.  

 

Another thing to check is the springs that hold the brushes in place - stretching these slightly could help as well. Don't stretch them much though - it will cause the brushes to wear out more quickly.

 

This of course all assumes that brushes do prove to be your problem.

[bud]

According to Yamaha parts catalogue. It's part number 4WP-81801-00.  They only list the SR from 1997. 

Flowers have this.  https://www.fowlersparts.co.uk/parts/4094542/sr125-3mw3-1992-999-a/demarreur-electrique

But it looks like no brushes.

[Yorky]

23 minutes ago, bud said:

Flowers have this.  https://www.fowlersparts.co.uk/parts/4094542/sr125-3mw3-1992-999-a/demarreur-electrique

 

I love a good typo

[bud]

48 minutes ago, Yorky said:

 

I love a good typo

Bloody auto correct on my tablet is a nightmare. Always changing what you write. And usually something nothing like you typed.

[billysugger]

I was writing a post the other day,and wrote I was semi retired. Auto correct changed it to semi retarded

Edited April 25 by billysugger
Spelling

[Emma]

I'm hoping to get the starter motor opened up today to get a proper look, I'm still very new to bikes though, this being my first bike and I've been doing all the work on it myself, with my brothers help. 

 

It was narrowed down to the starter motor and brushes, as the wiring is all good, starter clutch was recently repaired, new battery and the starter relay is working fine. 

I'm now researching opening it up and how to clean it so I don't muck it up today lol

 

From what I've seen while looking for brushes is that they are discontinued, hence trying to find ones compatible. But I'll have a look and see if I can bring some life back into my current ones with Hairsy's advice!

[Simon Davey]

16 minutes ago, Emma said:

I'm hoping to get the starter motor opened up today to get a proper look, I'm still very new to bikes though, this being my first bike and I've been doing all the work on it myself, with my brothers help. 

 

It was narrowed down to the starter motor and brushes, as the wiring is all good, starter clutch was recently repaired, new battery and the starter relay is working fine. 

I'm now researching opening it up and how to clean it so I don't muck it up today lol

 

From what I've seen while looking for brushes is that they are discontinued, hence trying to find ones compatible. But I'll have a look and see if I can bring some life back into my current ones with Hairsy's advice!

 

Sounds like good work so far. I wish I had your patience. 

Most big towns still have Motor-factors that refurbish starter motors and alternators. 

Maybe a local car repair shop could point you in the right direction? 

[Tinkicker]

1 hour ago, Emma said:

I'm hoping to get the starter motor opened up today to get a proper look, I'm still very new to bikes though, this being my first bike and I've been doing all the work on it myself, with my brothers help. 

 

It was narrowed down to the starter motor and brushes, as the wiring is all good, starter clutch was recently repaired, new battery and the starter relay is working fine. 

I'm now researching opening it up and how to clean it so I don't muck it up today lol

 

From what I've seen while looking for brushes is that they are discontinued, hence trying to find ones compatible. But I'll have a look and see if I can bring some life back into my current ones with Hairsy's advice!

 

Repair kit for mitsuba sm7.

https://wagendass.com/en/brush-holder-for-ford-briggs-stratton-mitsuba/12141-repair-kit-for-starter-mitsuba-sm-7-sm-7252-yanmar-73a81812-00.html?srsltid=AfmBOoqc4Sp95zkgc1BGuhu-83OWKs6qO4xKPp2hN-PpcbbLwm0DXEuy

Edited April 25 by Tinkicker

[Hairsy]

13 minutes ago, Tinkicker said:

 

Repair kit for mitsuba sm7.

https://wagendass.com/en/brush-holder-for-ford-briggs-stratton-mitsuba/12141-repair-kit-for-starter-mitsuba-sm-7-sm-7252-yanmar-73a81812-00.html?srsltid=AfmBOoqc4Sp95zkgc1BGuhu-83OWKs6qO4xKPp2hN-PpcbbLwm0DXEuy

 

Golden find!

 

I love this forum - on others you get told to Google it. On this one, people don't care that they've never met you and just give you a bit of their time.

[Emma]

Hi all! I wanted to thank you all so much for all the advice, I truly love the biker community, everyone's so helpful and friendly. I got the part and it's all installed, bike is running again. Taking her out tomorrow for work so we'll see if it all goes well! So happy I can get back on the road! 

[Emma]

On 25/04/2025 at 07:41, Hairsy said:

I'd suggest removing the starter motor (if you haven't done already) and then look for part numbers / manufacturer details for the starter motor itself (rather than the bike it's fitted to). You can then search for the brushes for that model of starter.

 

You may also find that with a little bit of every fine emery paper, you can clean up the existing brushes. This, combined with some contact cleaner, might kick the starter back into life.  

 

Another thing to check is the springs that hold the brushes in place - stretching these slightly could help as well. Don't stretch them much though - it will cause the brushes to wear out more quickly.

 

This of course all assumes that brushes do prove to be your problem.

Everyone's advice was so helpful, aswell as the links but I've marked your reply as the solution because I think it will help so many others with the same issue I had. I hadn't even considered looking at the starter motor part number rather than just searching in correlation to the make of my bike. Aswell as your advice for fixing up the brushes, mine did need replaced but that bit of knowledge will be handy to not only myself in the future but anyone who comes across this thread! Thank you!