Starter motor gear shaft problem?

[OldschoolGS]

Hi guys! I have a 1986 Suzuki GS 450 L. The bike sometimes start and sometimes does not. I think it's a starter gear shaft but I'm not sure. Here are some pictures of the starter motor that I have taken down from the bike. What do you think?

 

[rphillips]

I'd think that gear has nothing to do with the problem you explain... Any more info. when it doesn't start what does it do? Click?, grunt?, just spin but not turn eng.? When it does start does everything seem normal?

 

[OldschoolGS]

I hear a click, and the engine doesn't turn over. I thought the problem was the starter relay, so I replaced it. But I still hear the click, and again the engine doesn't turn over. I started it by push-starting, and after that, it started 4-5 times without any issues, right away. Then, the same thing happened again. I hear a click, and it doesn't want to start. When it starts, it runs perfectly fine without any problems.

 

[Rich82GS750TZ]

Get your volt meter out and put it to your battery. Give us these numbers. You could have a (not) charging issue.

1) Key Off - ? VDC
2) Key On - ? VDC
3) idle 1500 RPM - ? VDC
4) at 2500 RPM - ? VDC
5) at 5000 RPM - ? VDC
6) Key off - ? VDC​

 

[rphillips]

Thinking carbon build-up inside starter motor plus possible worn brushes. For kicks, next time it won't start put bike in gear, let out on clutch and rock bike back and forth bumping the eng. enough to change the position of the starter brushes on the armature. Then pull clutch and see if it may start.

 

[OldschoolGS]

I tested the starter motor. I connected the clamps to the battery, grounded the negative terminal to the starter, and connected the positive to the contact. It started to spin. I'll do all the mentioned, but first I need to put the motorcycle back together.

 

[OldschoolGS]

Also, what could be the problem if it starts after rocking it back and forth?

 

[GregT]

Also, what could be the problem if it starts after rocking it back and forth?

Starter motor brushes worn or dirty. When you rock it,you're getting the brushes onto another part of the commutator.

Job one after checking voltages as above is to pull the starter motor, strip and clean and check the brushes.

 

[rphillips]

Carbon build-up or worn brushes. The brushes got to make good connection on the armature shaft. rocking bike, bumping it back and forth, while in gear and clutch engaged will slightly turn eng. and turning eng will turn armature which can position the brushes slightly different and for sure at a different location on the armature. Not say'in that's the problem, just say'in it sure won't take long nor cost very much to try it.

 

[OldschoolGS]

Alright, thank you all guys! I'll try my best to get the job done. I'll keep you informed. Have a great weekend everyone!

 

[KiwiAlfa156]

I've had the same (intermittent) problem. Click, followed by either slow crank or no crank. I disassembled the starter motor, cleaned the commutator with Emery cloth, blasted out the starter motor with electrical cleaner, and replaced the relay with no real improvement. The starter worked perfectly if connected directly to the positive pole of the battery.

The issue turned out to be a bad earth (ground) between the mounting strap of the starter relay and the negative pole of the battery. As the current from the starter button has to pass through the relay to ground and back through the mounting plate, screws, frame tubes, another screw, and a earth (ground) strap back to the battery. Corrosion, paint and or dirt between any of these joins adds resistance to the circuit and can stop enough current passing through the relay for it to work properly and the full current from the battery isn't applied to the starter.

I now modify all my GS with a ground directly from the starter relay mounting strap to the -ve of the battery. Problem solved.

 

[Brendan W]

Another vote for opening the motor. As the brushes wear down it's easier to get jammed in the slots.
Make a careful inventory of the washers on the rotor. There could be a bunch of them at the drive end.
Look for any sign that the armature is touching the magnets and check the magnets are not separating from the casing.
A quick test for a bad earth return path is to stick a voltmeter between the crankcase and the battery negative when cranking.
Anything more than a tenth of a Volt could mean a bad return cable.

 

[KiwiAlfa156]

.
A quick test for a bad earth return path is to stick a voltmeter between the crankcase and the battery negative when cranking.
Anything more than a tenth of a Volt could mean a bad return cable.

True, but the issue with the relay not being well earthed is not a bad earth though the crankcase, which is the earth for the starter motor but not the relay.

​​​​​​If this earth is bad, there is often enough electromagnetic force to 'click' the relay but not enough to make a good contact between the battery and the starter through the relay.

 

[OldschoolGS]

Hi guys, I opened up the starter motor, and it’s going to need a lot of cleaning. I also checked the brushes, which are at the service limit (9 mm). I searched for new ones, but now I've found a used GS 500 starter motor in very good condition for the same price. There's only one thing bothering me: does a GS 500 starter motor fit on a GS 450? It looks exactly the same in the picture.

 

[Grimly]

Look up the part number and do a search.
I see Partzilla have stopped doing their very useful x-match on parts, which used to allow you to see if a part was cross-fitted to many models.

 

[Brendan W]

These guys still do a model compatibility check.
https://www.cmsnl.com/products/moto...01/?recommId=0369c30106a0894760d7396d31bf958e
On first look the part numbers for the 450 and 500 are different.
That does not mean that the parts are.

 

[Grimly]

According to Adept Power Sports (thanks to member dgates1 )
It fits a few other models...
https://www.adeptpowersports.com/oem-parts/suzuki-motor-assy-starting-31100-30b00-h17-part.html