Sticking starter motor

[kwallace21]

Hi folks,
Advice needed. Battery seems good but when starting I push the button, nothing turns for about a second and the display disappears briefly before the starter fires up and starts the engine. Motor spins fast when it's starting but I think it's jamming initially.
Am I correct ?

 

[Santa-2512]

Check all the leads for good earths

Remove clean and refit connections from battery & starter.

And earth block on the top of the engine,

If you feel brave, pull the starter motor, and have a look at the brushes & bendix

If you do a search, there are plenty of threads on here on how to do it

Mart

 

[Woland]

Test the battery.

 

[Bendy toy]

Use jump leads to test connections. Negative direct from battery to bare metal bolt head on engine proves the earth side.
Positive can be touched direct to the the stud on motor end.
If one spins the motor properly you know where to look. If neither make any difference it's the motor probably brushes.
Jump leads from another good battery will prove if the bike battery is failing.
If you use the car don't start it's engine.

 

[kwallace21]

Check all the leads for good earths

Remove clean and refit connections from battery & starter.

And earth block on the top of the engine,

If you feel brave, pull the starter motor, and have a look at the brushes & bendix

If you do a search, there are plenty of threads on here on how to do it

Mart

Mmm, where exactly are these connections. Imagine I know shit all about bikes.
Ta

 

[Bendy toy]

Do the tests I suggested with jump leads and go from there. The main negative (earth) connection is on the top of the engine just behind the alternator. It's common for corrosion to affect the electrical contact. Petrol tank has to be removed to access.

 

[kwallace21]

Mmm, plugged in the battery charger and it reads a maximum of 12.7 volts when charging. Remembered I had a brand new unused battery in the garage and it reads over 14 volts when charging. U know it's not under load but it might be the Motobatt that's on its way out. I'll swap them and see.

 

[AustinW]

A slow starter motor is a common problem on these bikes. Some seem to go on forever like that, others like mine go slow then fail almost completely after a while. I tried the cheap solutions first - putting extra +ve and -ve leads direct from battery to starter motor, which improved things a bit, then a new battery, again a bit better. A replacement starter motor though had everything whizzing around like I had never heard since I bought the bike, and I have never heard another GS1200 spin over as speedily as mine does now. I got an "Arrowhead" starter via a local car electrical workshop. I think the same Arrowhead model of starter fits for either the Valeo or the Bosch starters that are fitted to GS1200s (Valeo on older bikes, which are physically an inch or so longer than Bosch).

Replacing a starter is very easy: disconnect battery. Find your starter. Undo the nut holding the big thick +ve cable. Undo the smaller wire to the solenoid. Move both wires out the way. Undo the two mounting bolts - one is a bit awkward as its under and behind but with a bit perseverance and a "wobble" socket extension its easy enough. Wiggle the starter out. Replacement is the same in reverse.

There's a good thread on here somewhere about stripping and repairing a starter motor.

Good luck.

 

[Bendy toy]

Austin is probably right about it being a weak starter.

Here's an easy enough test.

Clip voltmeter to battery. Start engine, volts should not go below 11 volts while engine is cranking. ideally more like 11.5V.
Jump lead the earth lead between battery and engine case.
If volts go down when cranking you have a dirty earth connection.
If volts stay the same your starter is weak so not drawing much power from battery.

 

[kwallace21]

It doesn't turn slowly. It just doesn't do anything for a second and the display go out.
When it does spin it's fairly quickly. I think it's a week battery.

 

[AustinW]

It doesn't turn slowly. It just doesn't do anything for a second and the display go out.
When it does spin it's fairly quickly. I think it's a week battery.

Thats the sort of thing mine did. I also wanted it to be the battery that needed replacing. A new battery might improve it, but not as much as a new starter.

 

[Bendy toy]

Either way, jump leads will prove if it is the battery.

 

[duckspeed]

Look up how to perform proper volt drop tests there's every chance it has a bad earth somewhere

 

[kwallace21]

Popped a new battery in and it fires up instantly hot or cold with no effect on the display. Motobatt was around 4 years old but was left all winter with no use or charging so not surprised it was on its way out.

 

[Woland]

Goes to prove my thesis that whenever you get any kind of strange/odd behaviour that is even slightly electrical in nature its usually caused by a bad/weak battery

 

[Bendy toy]

Popped a new battery in and it fires up instantly hot or cold with no effect on the display. Motobatt was around 4 years old but was left all winter with no use or charging so not surprised it was on its way out.

This is why I bang on about LiFePo batteries. They cost more than lead acid but are not damaged by standing unused.