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Issue with dead Thruxton

4K views 21 replies 12 participants last post by  Photonboy 
#1 ·
My beloved cafe'd thruxton as died by the side of the road today, went about 200 meters from my home and round a bend... and the engine cut out. It is def an electrical cut out, no noises just dead, kinda like the kill switch had been flicked.
SO, still nothing from her, cant get her going again.

I've torubleshot the following.

Kickstand
checked the plunger all is good no issue even tried shorting the wires for the stand just in case, not the issue.

Kill switch
nope flick flick flick, all is good there no reason for issue.

Fuses
All good no issues

Key Ignition
Had a couple off issues where I had to jiggle the key even in the on position to get the bike started a few weeks ago, but hasn't been a problem since. I tried varios jiggles and poitions to see if there was a loose or bad connection. doesnt seem to be a problem here. I followed the wires into the headlight and double checked all cables and connectors were good there too.

Alarm
check connects all seems good

The bike wont try to start, I get nothing when I hit the starter. It's like the bike is immobilised/ kill switched.

So here is a perhaps related problem. Recently I havent been getting a Nuetral light, in fact the bike it would appear doenst ever seem to think its in N. I had to flick the stand up to start the bike in the last week. For about a year, I could start the bike without having to hold the clutch in, until about a week ago when i gave the bike a good service and re lube. Then I had to hold in the clutch as per normal but the stand had to be up. Clear indicator the bike thinks it's in gear all the time. This wouldn't have lead to the bike dieing going down the road tho.
Another troubleshoot. My alarm isnt giving me the self arming blips it normally does just before arming, it just arms. this has happened only after the bike died.
So I'd like to find a block to take the alarm out the equasion but I don't have one on me and I'm pretty stuck. It's pretty easy to point the finger at the alarm but I'm thinking it's something else. Plus I'd like to get it going asap. The whole no N light issue is the thing thats confusing me tho.

Anyway. Thats about the best description I can give in the hope that the internets can save me.

Thruxton 2003 Carb.

many thanks in advance to anyone with a similar problem solved or a solution!

thanks
 
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#2 ·
If you look on your wiring diagram you should see what needs to be jumpered if the alarm is removed.
That would eliminate the alarm as being faulty.
At least it's that way on my Hinckley triple.
Your neutral light bothers me though.
Might be something going on there.
 
#3 ·
Ya gotta love it. Mommy Gubbamints, who regard us as too stupid to pull the clutch or put up the sidestand, have mandated no fewer than four items designed to make the bike NOT GO! I guess the bike is safest when stationary, in their view.
Kill Switch
Neutral Switch
Sidestand Switch
Clutch Switch
I've nobbled the last two.
The alarm (I don't have it) seems to be a plug-in module, I believe through a connector under the seat. You should be able to remove it from the equation by just unplugging it.
Flicking the kill switch doesn't tell you much, you have to jump it.
I suspect the neutral switch/circuit. Take the wire off the switch and ground it (it's in the ground circuit for the warning light.
Worst case: It's in the Ignition Control Unit (let us pray.)
Redhawk
 
#5 ·
well it's not the battery, because all electrics are good. Headlight indicators, horn and alarm activates and deactivates, all got power.
The alarm does unplug but you must put a jumper block into the loose end to have a workable bike. My jumper is with my 675 which is in storage miles away and I only have one. (note to self, get another!)
I too think the N light and the clutch switch is a problem, but still not one that would have killed the engine while in motion...
I will try to head for my other bike and take the jumper of it and take the alarm out the troubleshooting.

Any similar stories, solutions?
 
#7 ·
Pick up coil?

Have you tried the pick up coil? A couple of years ago I was riding and the bike just died on me. Had power but would not start. Pushed it home then towed it to the dealer. Found out that the pick up coil was bad. Dealer said it was common.
 
#11 ·
Key Ignition
Had a couple off issues where I had to jiggle the key even in the on position to get the bike started a few weeks ago,

This would be where I would look closer, if this was a problem previously it's unlikely to have fixed itself permanently. Inside the lock barrel the wires are soldered to contact points which can break free (ask me how I know). As others have stated there are no shortage of switches that can fail and cause this but that's my 2 bob.
 
#12 ·
hmmm, you might be right, that would be something I'd like to take out of the equasion too. I don't have a wiring diagram to work out how to "hotwire the bike" then I could single the problem out to the ignition key.

Any tips? go into the headlight and unplug the ignition key, then short the right connectors....?
 
#13 ·
actually I just found a wiring diagram and got my multimeter out.

Ignition, Tested, no problems
Kill switch, Tested, no problems
Starter switch, Tested, no problems

...
So i'm going to catch the train to my 675 and take the jumper block off that for the alarm and see if it's my alarm... otherwise what else is in the loop that would'nt allow the starter motor to kick in and that caused my bike to just die by the rod, when all the other elects and battery are fine?
presumably that just leaves
The ignition control unit
The alarm
The rectifier?


....
 
#18 ·
The solenoid would be testing for the presence of of 12 volts at the coil trigger terminal when the start button is pushed.
Ignition coil can really only be tested on the primary side with a DVM because the secondary has a diode that requires a higher voltage to open than a DVM supplies.
All other tests would just be looking for voltage or continuity at different points using the wiring diagram to troubleshoot.
 
#19 ·
well when I shorted the solidoid the starter kicked over but the bike had no ignition to spark. So the engine is ok its clearly an igniton problem. I dont get the oil pressure light when I turn on the ignition. Although I checked the ignition switch, I get the feeling that thats the problem and inside its doing something its not supposed to.
It went on the back of a truck to the dealers and I booked it in for a service at the same time.

I'll post what the outcome was just for the sake of our Knowledge base :)
 
#20 ·
So it turned out that the loom going into the back of the headlight had become unseated to the rubber gromit that encirlces the headlight hole. The metal hole had been slowly cutting into the loom and making the wires short out all over the place. the clutch and headlight and oil light had all blown. The loom has been repaired and the gromit replaced. Since then the bike has been working fine.

I suppose, it's obvious now given the situation was clearly electrical, that it's worth (if possible) to trace any wiring and anywhere it could ground through. So nothing needed replacing, other then some bulbs and a bit of rubber... just the labour costs...

Thruxton is alive again :)
 
#21 ·
That's weird that no fuses blew. Thanks for the info though, yet another place to look. My bike had similar issues but it originated from the O2 sensor being rubbed against the engine from my aftermarket pipes and shorting those wires out. I would constantly blow fuses every time I turned the key. New pipes on the way...
 
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