Starting Problem

[Suzuki_Don]

GS550 with 650 top end. Bike starts fine on kick starter. Bit hard to get it going when it's cold in the morning though (5am).

With fully charged battery (gel type) 12.8v when starter depressed the engine turned very slowly - volts dropped to 8v. Finger off starter button, ign still on volts returned to 9.2v. Tried button again and just a humm from deep in the bowels of the engine somewhere (probably starter motor).

Changed to another good battery, fully charged as well. This time voltage dropped to 8v again but engine did not turn at all and again humm coming from down in the engine somewhere. Volts returned to 9.2v again.

Bike starts on kick starter ok and runs and rides ok and charges ok. Good lights when riding at night.

Any ideas where to look first. Starter motor or starter clutch? Solenoid not clicking -- could it be a possibility.

Thanks

[uk gs nut]

The brushes in the starter motor could be worn, or it could just need a good clean and re lube. Look for starter motor rebuild theads with the search opption.
Dennis.

[Steve]

With fully charged battery (gel type) 12.8v when starter depressed the engine turned very slowly - volts dropped to 8v. Finger off starter button, ign still on volts returned to 9.2v.

Sure sounds like it's time for a new battery.

.

[Suzuki_Don]

Sure sounds like it's time for a new battery.

.

Steve I tried two different fully charged batteries -- 12.6 - 12.8v.

[Guest]

Hey Don, sounds like maybe where I was at a while back...

To rule out the starter solenoid, get a big screwdriver and short across the two terminals. If it cranks over nice, you know it's your solenoid, otherwise it could be the starter.

In my case, it started better when cold but very rarely started easily when hot, which for me ruled the battery out straight away. I was still getting my carbs right so she'd idle nicely in peak hour which meant occasional stalling in traffic... no fun having to bump start in that!

I took the starter out and two of the four stationary magnets were no longer stationary and had jammed up against one of the others out of position.

I gave the commutator a light sand to clean it up and the bushes weren't great but were still serviceable, so I left them be.

On a suggestion from one of the guys over on Katana Australia, I used JB Weld to stick the magnets back in place, put it all back together, and she's still starting well a few months later...

[Suzuki_Don]

Hey Don, sounds like maybe where I was at a while back...

To rule out the starter solenoid, get a big screwdriver and short across the two terminals. If it cranks over nice, you know it's your solenoid, otherwise it could be the starter.

In my case, it started better when cold but very rarely started easily when hot, which for me ruled the battery out straight away. I was still getting my carbs right so she'd idle nicely in peak hour which meant occasional stalling in traffic... no fun having to bump start in that!

I took the starter out and two of the four stationary magnets were no longer stationary and had jammed up against one of the others out of position.

I gave the commutator a light sand to clean it up and the bushes weren't great but were still serviceable, so I left them be.

On a suggestion from one of the guys over on Katana Australia, I used JB Weld to stick the magnets back in place, put it all back together, and she's still starting well a few months later...

Thanks Pete, some good suggestions there. I will look into them.

[Guest]

Hope it's of some help Don... forgot to say I do have some pic's here too if they're of any help:

http://s594.photobucket.com/user/starpoint73/library/GS450/Starter?sort=3&page=1

[koolaid_kid]

The solenoid is just a switch (when taken down to its most basic form). It will not pull down the battery as you describe.
Since you have tried two batteries, the starter is most assuredly the culprit. Just be prepared for some carnage when you pull it apart.
Best of luck.

[Steve]

Steve I tried two different fully charged batteries -- 12.6 - 12.8v.

Even a poor battery can be "fully charged", but still fail miserably.

Just for 'fun and games', use jumper cables to your car (car not running, of course) and repeat your starting efforts and voltage measurement.
If the voltage stays up, I would still go with the battery.

.

[posplayr]

Even a poor battery can be "fully charged", but still fail miserably.

Just for 'fun and games', use jumper cables to your car (car not running, of course) and repeat your starting efforts and voltage measurement.
If the voltage stays up, I would still go with the battery.

.

As we all know it is best to check your battery before doing any electrical tests. As Steve is eluding you can detect battery health from battery voltage but it best done by applying a load and insuring the battery can support the current without dropping too much. I have never like using a starter test as a battery load test for several reasons and one of them is what I think is the present case that the starter is dragging and pulling more current.
Having switched out two different batteries leads us to believe that the battery is not the issue but by paying Attention to the first step in the Quick Test you could have determined the battery state just using the gs standard loads.

If you have a bad battery and want to start what is an otherwise operation bike there is probably no harm in starting with a car battery. However in this case where the starter is suspect, I don't see the upside of trying to force even more current through the poor dragging starter. If As Pete found one of the magnets has jammed and creating great friction, the current in the starter is probably approaching stall but the drop in voltage from the battery is tending to limit the current. Putting a larger battery in its place would only surge to get cl?ser to true stall current and this will only stress the starter and wiring well beyond it's normal operating currents.

[Suzuki_Don]

Thanks Jim, it looks like I will need to pull the starter which I guess is nigh impossible on a 550 while the carbs are in place. I did give the starter the once over when I restored the bike about 5k ago -- disassembled it, cleaned it out, the brushes were fine with plenty of length available, cleaned the commutator, etc. But that's not to say something in there has not come adrift in the meantime.

It's like a short almost is being put across the battery when I try to start it via the starter motor. It starts ok on the kick starter. The volts drop from 12,8v to 8v and then back up to 9v with starter released and ign ON.

Thanks for ALL contributions from the different sources.

[Suzuki_Don]

Hope it's of some help Don... forgot to say I do have some pic's here too if they're of any help:

http://s594.photobucket.com/user/sta...?sort=3&page=1

Pete -- thanks for the pics

[posplayr]

Thanks Jim, it looks like I will need to pull the starter which I guess is nigh impossible on a 550 while the carbs are in place. I did give the starter the once over when I restored the bike about 5k ago -- disassembled it, cleaned it out, the brushes were fine with plenty of length available, cleaned the commutator, etc. But that's not to say something in there has not come adrift in the meantime.

It's like a short almost is being put across the battery when I try to start it via the starter motor. It starts ok on the kick starter. The volts drop from 12,8v to 8v and then back up to 9v with starter released and ign ON.

Thanks for ALL contributions from the different sources.

The way a DC motor works on startup is the current is only limited by the internal resistance. As the motor speeds up, the starts to act like a generator and develops back emf. As the back emf comes up the current drops off. The faster the motor goes the lower the current for a given voltage. That is why when you stall a motor and. Don't allow it to spin the current really climbs. Fortunately the moto batteries are relatively small so the internal battery resistance is relatively high which tends to limit the current even if stalled. The car battery has more capacity and lower internal resistance and could easily add 50% more current to a stalled motor.

[Suzuki_Don]

The way a DC motor works on startup is the current is only limited by the internal resistance. As the motor speeds up, the starts to act like a generator and develops back emf. As the back emf comes up the current drops off. The faster the motor goes the lower the current for a given voltage. That is why when you stall a motor and. Don't allow it to spin the current really climbs. Fortunately the moto batteries are relatively small so the internal battery resistance is relatively high which tends to limit the current even if stalled. The car battery has more capacity and lower internal resistance and could easily add 50% more current to a stalled motor.

Thanks Jim

[Suzuki_Don]

Well it loooks like both of the batteries I was using were on the way out. I used an "old" car battery I had in the shed and hooked it up to the existing battery and the starter cranked the engine without any problems. I am getting a new MotoBatt MB10U battery tomorrow, it will only cost me $120 and has a two year warranty on it. I will see how that cranks and if it solves my issues.