Odd Start Up Problem

[Psycheonabike]

Hi everyone,

I have a problem when starting my GL1200 (1985).

When pressing the Start button the lights dim but she won't crank. Battery showing 12.5V. Got up this morning and she started fine (very cold and misty) rode 55 miles and tried to start her after parking up....same again, lights dim but wont turn over.

Any ideas? I have ordered a Starter Solenoid and new battery for now as she will start first time when using jump leads from a small car battery.

All I have done to her is put new spark plugs in.

Thanks

[DenverWinger]

Any ideas? I have ordered a Starter Solenoid and new battery for now as she will start first time when using jump leads from a small car battery.

That's a good place to start (so-to-speak)

You might want to check the starter motor for worn out brushes, too...

[Psycheonabike]

There's also a possibility that the battery might not be up to scratch - although its new the previous owner got the cheapest one they could fine. Would that affect running/performance too?

[DenverWinger]

If it's new, even a cheap battery should be able to start a 1200... Would not affect running or performance, just starting.

Worn out starter brushes can cause the starter to pull much more power from the battery than normal, at the same time delivering less torque to spin the engine....

[Psycheonabike]

Thanks,

Is a starter overhaul a big job?

[DenverWinger]

Not really.. The hardest part is getting it off the bike. Brushes are cheap.

[Psycheonabike]

Thought I'd test to see how much voltage was being pulled from the battery when pressing start button. Turns out there was almost none going from 12.2 to 12.1 (I think battery is on the way out anyway given how much its holding) but oddly the lights all dimmed too. I'd just got back from a 50 mile ride as well.

One more thing, battery had been on charge all day and when put back on the bike she started first time.
Does this sound like its just the battery is the source of the problem?

I've a Yuasa in the post to replace the suspect one.

[DenverWinger]

12.2 is not correct for a "Charged" battery, should be around 12.6-12.7 volts no-load. Check alternator, too. You should see around 13.5-15 volts at the battery at 4000 RPM...

[DaveO430]

Turns out there was almost none going from 12.2 to 12.1 (I think battery is on the way out anyway given how much its holding) but oddly the lights all dimmed too.

The headlight going out has nothing to do with starting, there is a separate contact in the start switch that shuts off the headlight. If everything else goes dim you have a bad battery or a bad connection.

[Psycheonabike]

Okies....

So I seem to recall someone asking someone else on another forum with a similar issue - 'does it start with the clutch pulled in'?

So I tried that and now she starts......? I gather there is a cut off sensor going wrong somewhere?

[WingAdmin]

Okies....

So I seem to recall someone asking someone else on another forum with a similar issue - 'does it start with the clutch pulled in'?

So I tried that and now she starts......? I gather there is a cut off sensor going wrong somewhere?

Well it isn't supposed to start without pulling in the clutch if the bike is in gear.

If the bike is in neutral, and you STILL have to pull the clutch in to get it to crank, then you need to look at the neutral switch, neutral switch wire, and diode.

[Psycheonabike]

Thanks...on it! Another job for the weekend!