'97 Bird. Intermittent cutouts. Help!

[JonoMcB]

Hey guys, I?d like to pick your brains over my poorly Blackbird and I?d appreciate your input.

Cutting out notes:

?97 model

Having infrequent total losses of power.

Quite clear cutouts ? not just losing power, but no power at all and hard into engine braking

First time 2nd /3rd gear, moderate acceleration.

Cut out, clutch in, engine stopped, clutch back out engine braking but didn?t bump start.

Pulled over. Hitting the starter turned engine over easily, but cylinders didn?t fire at all.

Tried this a few times then waited a few minutes, wondered if it was the side-stand so wiggled it and tried again.

It worked immediately. Rode 10 miles to work, 13 miles back with no further problem.

That night I cleaned up the sidestand switch and connectors, WD40?d it in case it was water-ingress and all seemed well.

Next day after 10 miles/15 min it stalled as I pulled away, then restarted for a second or two, then cut out again for a few seconds, had a backfire or two then started and was ok for the rest of the journey to and from work.

Tonight I ran the engine in 1st gear on the centre-stand and tried to provoke a problem by wiggling connectors around battery/fuses/diode but couldn?t cause a cutout.

I also confirmed that if it was the side-stand switch that was the problem then it bike wouldn?t have turned over at all, same applies if it was the killswitch.


So now I?m left unsure what the problem is and I don?t trust my bike not to cut out at the least convenient and/or most dangerous time.

I?m moderately techie at best and the intermittent nature of the problem makes me worry I can spend evenings chasing it down and never get anywhere.

Any ideas chaps?

 

[CBRDEAN0]

Someone has just had this sort of issue - I'm sure it was caused by one of the wires under the ignition switch being broken.

 

[silverfox.xx]

Ignition switch wire, underneath it, they can cause pribs.

 

[silverfox.xx]

Great minds eh.
Carb will back fire if electric lost, then come back.

 

[JonoMcB]

OK, thanks for that, before I take the front of the bike apart...

Can I just confirm - it's an intermittent problem, wouldn't a broken wire be more of a complete problem?

How come the starter, lights etc. still work? does the broken wire on the ignition barrel just control power to the spark or something?

 

[silverfox.xx]

The ignition switch has 3 wires, and the starter circuit is seperate.

 

[Me!]

The broken wire may not be broken but hanging on by a few strands....

 

[silverfox.xx]

Or the soldered joint on the bottom of switch has detached itself, and the tension on the other wires are holding it against its 'contact's point... Occasionally.

Start bike, wiggle wires to bottom of switch, my guess is bike'll stop.
It's happened on 6 or more bikes.

YES lights are on a separate wire.

 

[Murt]

Sounds just like the problem I had. (97 bike).

It was a loose wire under the ignition switch.
Water had got in over the years, one wire was just on by a thread after corrosion.

Have a search for it, photo's and everything!

Cleaned with ACF50, re soldered and as good as new.

Unfortunately, you can only get at it after taking the bars off!

Murt

 

[CBRDEAN0]

Have a look here - http://www.bikersoracle.com/blackbird/forum/showpost.php?p=685182&postcount=2

 

[JonoMcB]

Cheers guys.

Work has come to a halt when I discovered that somehow I have managed to live my life so far without a 12mm Hex bit on a 1/2" square socket...

Trip to Halfrauds on my lunchbreak beckons...

 

[Murt]

Don't forget they are 'security' hex. They have a little lump in the middle to stop tampering. A little dremmil to grind the lump down works.
Or a centre punch.

Good luck with it.

Murt

 

[JonoMcB]

So...

I have removed the top yoke and ignition barrel.

The wires inside look absolutely fine, strong and thick with little or no evidence or corrosion or fraying.

Nothing at all like Scatman Dave's photos of his.

Any suggestions of what to do next? or anything I can fiddle with with a multimeter to try to provoke the fault and spot it?

Any chance of the problem being INSIDE the barrel, rather than the wiring beneath?

 

[Me!]

Hmmm

Basics checked?
Battery tight?
Ignition key worn?
Cdi in holder and plugged in properly etc?

 

[andyBeaker]

I can't profess to have any specific ideas on this but you might eliminate some possibities by;

• undo and retighten any earth points you can find - including the main one from the battery to the frame. Earths are funny buggers - a continuity test can say it is OK but I have had one on a Fazer where the multimeter said it was fine but a quick spin on all the earths magically fixed an intermittent problem
• while others can probably be more specific, any cut out switch can be bypassed with a bit of snipping and soldering

keep posting, someone wiill have the answer............. eventually;-0))

 

[Me!]

Also worth opening the kill switch. Two screws underneath and spray some contact cleaner in there.

 

[JonoMcB]

Hmmm

Basics checked?
Battery tight?
Ignition key worn?
Cdi in holder and plugged in properly etc?

Battery connections checked, yes.
Earth points no - will check haynes manual unless someone can point me to them easily.

Ignition key worn? yes, probably, doesn't always turn easily/smoothly. How could this be the cause though? if it still rotates the switch under the barrel?

Cdi??? Its pre-immobiliser and HISS.

I really want to positively identify the problem, rather then just reassemble it all and then everything seem fine until I'm in the middle of an overtake...

Frustrating and scary.

 

[JonoMcB]

Also worth opening the kill switch. Two screws underneath and spray some contact cleaner in there.

? unlikely as the starter turned over and kill-switch stops the starter circuit, unless I've misunderstood something.

 

[Me!]

? unlikely as the starter turned over and kill-switch stops the starter circuit, unless I've misunderstood something.

True but it's also designed to 'kill' the engine so if there's a fault in it surely its a possibility for it to be cutting power....

 

[andyBeaker]

The main earth is from the earth on the battery to the frame - from memory it is a strap that has a bolt going through it on the right side of the battery as you sirt on the bike. Others wil be more specific - there will be others scattered around.

Has the bike got an aftermarket alarm/immobiliser??