Starter motor

modelman · Post by **modelman** » Mon Oct 30, 2017 8:10 am

And the questions just keep coming!!
Before the complete stripdown starts, I want to ensure it all works, it hadn't run for many years, but as it was not seized ( unlike the other one) I fueled her up, fitted a new battery, sorted the spaghetti wiring, & 3 kicks later she was running very nicely.
The starter however is 'lazy', so I removed it, hooked it up to a big battery & she spun like a good-un, then it didn't, then it did!! EH!!
Stripped it down & the brushes & commutator look new, completely smooth, no scratches or marks, a good deep undercuts, brushes also look new, long & clean.
Got the meter out & started to check continuity etc. but can not find any meaning, as some segments have continuity, others do not, also, only 2 carbon brushes & they are at 90 degrees & not 180, so is the construction of these motors arranged different to the norm??
I need an electrical expert to tell me correct way to check these out, physically the motor is as new, I suspect by the way it runs intermittently, that there must be a armature breakdown somewhere, but how to check, do I meter adjacent segments, every other, one to all or what??

Geoff Hastings · Post by **Geoff Hastings** » Mon Oct 30, 2017 9:05 am

I just pulled one of mine apart and did a continuity check. All the segments read 0.1 ohm to each other, ie I put one probe on the first segment and then got the same reading all the way round. I then popped it back together just to check nothing had gone amiss while sitting on the shelf and it still functioned fine. Just to clarify, I touched the first and second segments, got 0.1ohm, then the first and third segment and so on all the way round.I then did random segments with the same result. The point one of an ohm is just what the Meter reads with the two probes touched together so is not an actual value for the windings, might need a new battery in my meter.

modelman · Post by **modelman** » Mon Oct 30, 2017 12:46 pm

Well I tested it all out, I get readings on some, zero on others, put it back together, hooked it up to a car battery & it runs! Not a big 'jolt' & then a good speed run like others I've messed with, just runs!
Whacked it back on the bike, pushed the button & it sort of halfheartedly started to turn, then stopped, just like when you have a flat battery, so now I have to try & find someone who can re-wind a motorcycle starter armature, if thats possible!!
A real shame as if you look at it, its like new inside, & finding a replacement is like finding rocking horse poo.
BTW, I get full voltage at the solenoid & down to the motor, new high capacity AGM battery from the CB & it whizzes that motor no probs.

DJM · Post by **DJM** » Mon Oct 30, 2017 1:48 pm

Are you sure that the problem isn't in the starter solenoid.

The contacts can become burned and pitted leading to intermittent connection and just the symptoms you describe.

Good news is that the solenoid can be dismantled - WITH CARE, to clean up the contacts which should restore normal operation of the starter.

Also worth checking that the main earth cable from the battery to the rear engine mount is clean and tight. Same goes for all the connections / terminals on the battery, solenoid and starter motor.

modelman · Post by **modelman** » Mon Oct 30, 2017 3:04 pm

Yes, thanks for that, I too thought that & will be checking it all out tomorrow.

Geoff Hastings · Post by **Geoff Hastings** » Mon Oct 30, 2017 5:25 pm

Sorry to disagree, but, if the starter motor did not work consistently when off the bike surely the solenoid was not in use. The trouble with using a multimeter to check out the starter circuit is it will register 12volts from battery to starter but the motor needs lots of amps. A multi meter will read a fart in a storm but not how much it stinks! The solenoid can make contact enough for the meter to register 12volts but once a load is applied the burnt contacts won't allow enough oomph to pass to power the motor. You could bypass the solenoid and apply the 12volts directly to the motor.

modelman · Post by **modelman** » Tue Oct 31, 2017 12:48 pm

Today I pulled all the starter wiring & cables, cleaned all connectors, terminals & contacts.
Re-stripped the motor, nothing obvious, re-built, re-fitted, hooked it all up, & the bloody thing works!!
The annoying bit is, I don't really know what the problem was, but I suspect it was dirty wiring connections.
Thanks to everyone who helped.