Wouldn't start - Help

[fazersharp]

Out for a ride and after 35 miles I stopped for 5min and it started back up ok after 2 little presses - which is a bit unusual as normally it fires up just by looking at the start button  .
Then another 10 miles and stopped for petrol but it would not re start. Turns over perfectly fine for about 1 second and at the point it usually fires up everything stopped and three was a Brrrr sound from under the seat.Tried it about 8 times and the same thing each time.It started no problem straight away bump staring it to get home.At home I re started it 4 times without any issues at all. The Brrrr noise was like if you had a small piece of playing card between an elastic band and twisted it loads of times then let it go onto a matchbox. It sounds somewhere near the battery, I had the seat off and listened and pressing the rear mudguard plastic near the batter I could also feel the Brrrr noise.
The battery is 26 years old original to the bike and is kept on a trickle charge.  Any ideas ?Thanks     

[fazersharp]

As extra background info I didn't ride much November to Feb and had 10-12 weeks between rides during that time and it has been reluctant to start, I put it down to the bike telling me off for not riding   
So much so that after a few attempts the battery sounded like it was getting sluggish so I put it back on the trickle charge for 30 mins - try again and it starts almost straight away.  But I have noticed when I stop for fuel it has been taking a few go's to get it started, although it seems strong enough turn over from a battery point of view.
Maybe I need some new spark plugs as the last time I changed them was Jan 2012 but average 1,000 miles per year =12,00 miles to now but will need to check MOT for exact mileage.
This was the last time I had staring issues in 2012 https://foc-u.co.uk/index.php?topic=26060.msg312220#msg312220

     

[Grahamm]

It sounds somewhere near the battery, [...]
The battery is 26 years old original to the bike and is kept on a trickle charge. 

I'd suggest putting a Drop Tester on the battery, because after all that time, it's probably dropped a cell and you're not getting enough Cold Cranking Amps.

The buzzing is most likely your starter relay: When you press the button, the relay latches so current can pass through to the starter motor, but that pulls too much power, so the relay unlatches, meaning there's now enough current to latch the relay again, but...

[BBROWN1664]

Sounds like the battery has finally decided it needs to retire. Using Jump leads or a jump pack will prove this.

[fazersharp]

It sounds somewhere near the battery, [...]
The battery is 26 years old original to the bike and is kept on a trickle charge. 

I'd suggest putting a Drop Tester on the battery, because after all that time, it's probably dropped a cell and you're not getting enough Cold Cranking Amps.

The buzzing is most likely your starter relay: When you press the button, the relay latches so current can pass through to the starter motor, but that pulls too much power, so the relay unlatches, meaning there's now enough current to latch the relay again, but...

thanks Its more of a super fast clicking than a buz.
What is a drop tester.   

[fazersharp]

Sounds like the battery has finally decided it needs to retire. Using Jump leads or a jump pack will prove this.

Seems like it. I know batteries do strange things when on there way out but it has recently been starting fine as I have ridden a little more and I couldn't make it do it again when I got home about 14 miles later. 

[Grahamm]

What is a drop tester.   

It's a device that you connect to the positive and negative terminals of a battery, then throw a switch to put a load on it.

It measures what are known as "Cold Cranking Amps" which is the amount of power the battery puts out and can tell you if a battery is good or not.

Find a friendly local garage and ask them to check yours, or you can buy them online for not much money, although given most batteries (even with a Optimate or similar tender) tend to last no more than 5-6 years, I would strongly suspect yours is well on its way out!

[fazersharp]

What is a drop tester.   

It's a device that you connect to the positive and negative terminals of a battery, then throw a switch to put a load on it.

It measures what are known as "Cold Cranking Amps" which is the amount of power the battery puts out and can tell you if a battery is good or not.

Find a friendly local garage and ask them to check yours, or you can buy them online for not much money, although given most batteries (even with a Optimate or similar tender) tend to last no more than 5-6 years, I would strongly suspect yours is well on its way out!

But its only 26 years old  (thanks)

[fazersharp]

The buzzing is most likely your starter relay: When you press the button, the relay latches so current can pass through to the starter motor, but that pulls too much power, so the relay unlatches, meaning there's now enough current to latch the relay again, but...

Ok been doing some more reading on here and found this explanation that describes what you have said, might be useful to others that come along reading. 

You probably know this already but a relay is just a magnetic switch that uses a low current circuit to control a high current circuit ( ie the small starter button on the handle bar is the low current circuit used to control the high current starter motor). They're used in the starting circuit so you don't have big thick wires running down the bike and a huge starter button They have two pins on the low current side (the starter switch side) which simplifying it a bit goes from the starter switch on the handle bar to the first pin of the relay, then the second pin on the low current side of the relay goes to ground. This powers a little electromagnetic coil in the relay. The electromagnet closes a switch on the high current side of the relay to complete the high current side of the circuit. There's two pins on the high current which go from the battery on the third pin, then the fourth pin goes to the starter and the starter grounds against the frame. The clicking sound you're hearing is the switch on the high current side opening and closing rapidly because the battery doesn't have the enough power energise that side of the circuit and spin the starter so it just clicks rapaidly. So a clicking relay is a good indicator that your relay is working but your battery power is low and needs to be charged or replaced if it doesn't hold a charge. Hopefully that makes sense. You can jump it off a car as long as the car is turned off or you can put it in second gear and push start it.

Just to expalin energise high current starter bit in more details:

When you push the starter the starter realy magnetic switch switches on. It needs certain amount of voltage and juice (ampers) in order to switch on and to stay switched on.

What is occurring in your case is that the starter relay engages.  This connects via high current switch in the realy the battery to the starter motor.  The starter motor loads the battery causing the voltage to drop but not enough juice to turn the starter. That starter motor load causes the battery voltage to drop, the reduced voltage is insufficient to hold the relay and it opens, disconnecting the battery from the starter motor.  The battery voltage recovers, because there is no started load present thus allowing the solenoid relay to re-engage and starting the switch on relay cycle all over again. Hence the rapid clicking.

[Grahamm]

Ok been doing some more reading on here and found this explanation that describes what you have said

Yep, that's the long version

[fazersharp]

In jan/ feb after not riding for long periods (it always takes longer to start the longer I leave it. )  it wouldn't start and after a few attempts I thought I had better stop as I could hear the battery getting sluggish so popped in back on charger for 30mins and started fine.
  What I dont get is that the battery was clearly low after a few attempts of starting so why did it not kick into the relay "spazam" as described at that point.
As far as I knew if you kept trying to start a non starter the battery would just get lower and lower until all you got was 1 click- but never the spazam thing

[BBROWN1664]

the 1 click is when it has enough power to try to turn over the engine but not quite enough to actually do it.
The spasm is when its even lower and just the act of throwing the relay dips the voltage to far that it releases it - voltage increases marginally and it tries again and again and again

[fazersharp]

I see - thanks.