Topic: Starter issue or just bad battery...again..CB550

[denward17]

About 4 weeks ago ordered a new Scorpion battery for the '76 CB550K I am refreshing.  It started with about 12.7v out of the box but would barely turn engine over.  With my cheap multimeter measuring volts while holding the start button, it would drop to about 6v.

Supplier thought the battery was damaged, so sent a new battery.  Got it today and out of the box it read 12.87v.  Hooked it up tried to start bike.  Same thing happened.  It would barely turn engine over then go flat.  Reading while holding the start button was about 7v.

Is this another bad battery or do I have an electrical problem?

Bike will start with kick start and runs good, although I had the headlamp/tail lamp fuses out.  With 2500RPM or so the battery would show about 14+ volts.

Forgive me, I am not an electrical guru, but can follow instructions.

Thanks for any assistance...

[bryanj]

New batteries should be charged before fitting

[BenelliSEI]

Den….. my cheapo AGM come charged and ready to go. That one sounds like it needs a charge. Are you certain something is not jamming in your starter motor or the spur gears? Probably not, as even that should not suck the battery down that fast.

Try just turning the lights on. Does that kill it fast too?

[denward17]

Paperwork with battery indicates it is ready to go.  Right now at 12.7v.

I did put the charger on it, will check later today/tomorrow.

[bryanj]

Voltage measurement is NOT  state of charge

[M 750K6]

Could you have a poor earth to the starter, or poor connections through the circuit to/from the starter button?

[denward17]

Could you have a poor earth to the starter, or poor connections through the circuit to/from the starter button?

I don't know but will pull off the trans cover tomorrow and check the connections.

[bryanj]

Trans cover wont show ground lead, check at rear top engine mount that bolt is tight and no paint either side of bracket

[denward17]

Upper engine mount bolt is torqued to spec, with dielectric grease.  Frame was touched up with paint, but I did sand the mounting points on both sides of clutch bracket, and on the outside of the upper bolt contact point on the left side.

Would that copper washer make a difference on the clutch cable bracket upper bolt?

[denward17]

After charging for 2.5 hours, voltage check was 12.8, turned ignition switch on with all fuses in and battery voltage dropped to 11.9.

Will let it trickle charge overnight.

[grcamna2]

Possibly check this next time you install the battery by:installing the + positive lead to the battery,then hooking a 12vt. test light between the Neg.- battery cable and the Neg.- battery post.
The bike may have a bare + connection touching the frame/starter?

[HondaMan]

Upper engine mount bolt is torqued to spec, with dielectric grease.  Frame was touched up with paint, but I did sand the mounting points on both sides of clutch bracket, and on the outside of the upper bolt contact point on the left side.

Would that copper washer make a difference on the clutch cable bracket upper bolt?

That ground lug goes in between the engine and frame on the long upper cross-bolt in your picture. Where it is now will cause losses between the aluminum engine case and the steel frame where they meet up.

[denward17]

Upper engine mount bolt is torqued to spec, with dielectric grease.  Frame was touched up with paint, but I did sand the mounting points on both sides of clutch bracket, and on the outside of the upper bolt contact point on the left side.

Would that copper washer make a difference on the clutch cable bracket upper bolt?

That ground lug goes in between the engine and frame on the long upper cross-bolt in your picture. Where it is now will cause losses between the aluminum engine case and the steel frame where they meet up.

Just so I am clear, the ground lug goes between the engine and the clutch holder bracket?

Mark, Are you referring to the bolt circled in the picture attached?

[denward17]

Possibly check this next time you install the battery by:installing the + positive lead to the battery,then hooking a 12vt. test light between the Neg.- battery cable and the Neg.- battery post.
The bike may have have a bare + connection touching the frame/starter?

Tried it, no light..

[HondaMan]

Upper engine mount bolt is torqued to spec, with dielectric grease.  Frame was touched up with paint, but I did sand the mounting points on both sides of clutch bracket, and on the outside of the upper bolt contact point on the left side.

Would that copper washer make a difference on the clutch cable bracket upper bolt?

That ground lug goes in between the engine and frame on the long upper cross-bolt in your picture. Where it is now will cause losses between the aluminum engine case and the steel frame where they meet up.

Just so I am clear, the ground lug goes between the engine and the clutch holder bracket?

Mark, Are you referring to the bolt circled in the picture attached?

Yep, that's the one!
The frame bolster is actually spaced outward there by 1mm wider than the engine to accommodate it.

[scottly]

After charging for 2.5 hours, voltage check was 12.8, turned ignition switch on with all fuses in and battery voltage dropped to 11.9.

Will let it trickle charge overnight.

What are you using for a charger? Battery "maintainers" may not put out enough voltage to fully charge a battery, which should be 14V or more. Check the voltage with your meter while the battery is on the charger.

[scottly]

With my cheap multimeter measuring volts while holding the start button, it would drop to about 6v.

Supplier thought the battery was damaged, so sent a new battery.  Got it today and out of the box it read 12.87v.  Hooked it up tried to start bike.  Same thing happened.  It would barely turn engine over then go flat.  Reading while holding the start button was about 7v.

You might have a bad starter, drawing way too much current? That's where I would start looking..

[denward17]

After charging for 2.5 hours, voltage check was 12.8, turned ignition switch on with all fuses in and battery voltage dropped to 11.9.

Will let it trickle charge overnight.

What are you using for a charger? Battery "maintainers" may not put out enough voltage to fully charge a battery, which should be 14V or more. Check the voltage with your meter while the battery is on the charger.

It's a Schumacher 10amp, but in auto mode it only pulses to what appears to be 2 amps.

[scottly]

Monitor the voltage while on the charger!!! Use a separate meter. DO NOT rely on the auto mode, as those stupid "smart chargers" get confused by our small batteries: they are programed for larger car batteries. If the voltage gets up to 14 +, shut the charger off.

[grcamna2]

Upper engine mount bolt is torqued to spec, with dielectric grease.  Frame was touched up with paint, but I did sand the mounting points on both sides of clutch bracket, and on the outside of the upper bolt contact point on the left side.

Would that copper washer make a difference on the clutch cable bracket upper bolt?

That ground lug goes in between the engine and frame on the long upper cross-bolt in your picture. Where it is now will cause losses between the aluminum engine case and the steel frame where they meet up.

Just so I am clear, the ground lug goes between the engine and the clutch holder bracket?

Mark, Are you referring to the bolt circled in the picture attached?

Yep, that's the one!
The frame bolster is actually spaced outward there by 1mm wider than the engine to accommodate it.

I think it will help to clean the back side of the frame(top/rear engine mount long bolt)for a better connection(engine paint?)where that - ring terminal goes between the frame and the engine case.
You want metal to metal contact, w/ a little dielectric grease to keep corrosion from forming later.

[scottly]

Upper engine mount bolt is torqued to spec, with dielectric grease.  Frame was touched up with paint, but I did sand the mounting points on both sides of clutch bracket, and on the outside of the upper bolt contact point on the left side.

Would that copper washer make a difference on the clutch cable bracket upper bolt?

That ground lug goes in between the engine and frame on the long upper cross-bolt in your picture. Where it is now will cause losses between the aluminum engine case and the steel frame where they meet up.

Just so I am clear, the ground lug goes between the engine and the clutch holder bracket?

Mark, Are you referring to the bolt circled in the picture attached?

Yep, that's the one!
The frame bolster is actually spaced outward there by 1mm wider than the engine to accommodate it.

I think it will help to clean the back side of the frame(top/rear engine mount long bolt)for a better connection(engine paint?)where that - ring terminal goes between the frame and the engine case.
You want metal to metal contact, w/ a little dielectric grease to keep corrosion from forming later.

The problem is not with a bad ground, which would decrease the current draw by the starter, instead of sucking the battery down to 7 volts.

[Ozzybud]

Looks like you have the ground lug on the correct bolt and in the correct location.
pic below is my CB550. It was virtually untouched when i purchased it and see no reason someone to move it,also
every other Picture on the internet shows it in that location.
You can check for a bad connection by checking for resistance between that wire and the frame/ engine. should be zero resistance.
I doubt that this is your issue,

[BenelliSEI]

I’m betting your vendor has a supply problem. That battery sounds pooched too.

[Stev-o]

I’m betting your vendor has a supply problem. That battery sounds pooched too.

Ive purchased several Scorpion batteries over the years, never an issue.

Den - you have a 750 battery , right?   I'd try connecting that to your 550 to check starter, etc.  [I know it wont fit in the battery box, just connect the cables and secure it somehow. Or jump it with your car]

[BenelliSEI]

Good idea, Steve.