Dead Bike - HELP !

[Voyager]

Typical . . .

I do loads of work on the bike in preparation for the Wee-Kend and then it conks-out on me when its too late to get parts

The bike is a 1989 R100 GS - as per my Avatar.

It has been running over the past few days, but I found water in the N/S float chamber, which necessitated a carb clean-out. It was running but tickover was erratic and it would eventually cut out.

I have balanced the carbs with a pair of vacuum gauges - OK.

Tested the ignition timing - nice strong strobe light and timing OK.

Bike was running fine on the road, the problem was just tickover.

The whole wiring loom was replaced with BMW components in 2007.

It is twin-plugged, new top plugs fitted yesterday (lower ones cleaned).

Coils are Dyna-Coils, new two years ago. They show 1.6 ohms each and there is continuity across the series connections.

Battery is a new Odyssey PC680.

I have just replaced the timing chain, which necessitated removing all the electrical gubbins from the front. It all went back together OK and the bike fired up fine when I finished the job.

Last evening I went to give the bike a run and fill the tank - but it wouldn't start. There was plenty of life in the battery, all lights work fine, starter was churning merrily - but not a sign of it firing.

I left it overnight with the battery on charge.

Today its the same - no spark at the plugs but everything else OK.

There is battery voltage at the coils when the ignition is turned on.

I have removed and re-made all 'black box' connections. Still no joy.

I had the 'bean can' apart last year and renewed the auto advance springs. It has been fine since, but I note that the three-pin plug and lead (which I didn't replace) is looking hard and old.

There is no continuity between any combination ot the three pins and none between any of them and ground.

I have sections 4.44 and 4.45 of the 80 GS manual printed off and will work my way through the tests with my multi-meter.

I suspect the Hall Sensor or its cable is knackered - does anyone have a 'Quick Test' procedure that will confirm/deny my prognosis ?

Unless I get a quick (and permanent) fix today, I'll be missing the Wee-Kend, which is a bummer as I was really looking forward to it.

Sods Law triumphs again

All clues gratefully received.

Thanks.

Bob.

 

[freeloader]

Sorry to hear that, Bob. I can't offer any helpful suggestions at all, just sympathy.



(Just hope I don't have any similar mishaps before I head off to Ullapool tomorrow.)

 

[John Armstrong]

Kill switch in the correct position?

 

[BillN]

Not read it the post thru completely yet

"Water in the float bowls" - where did it come from?

Have you taken the Tank off and emptied it to find out if there is any water in the Tank............plus cleaned the pet cocks............probably not this.......I have started putting in line filters in the fuel line as these tanks are now getting old and the original inside coating is breaking away

Presumably if you whip the plugs out after a few turns of the engine - they do smell of petrol - try squirting a bit into the cylinders and trying to start - just as something else to try

Also WD40 test around the carbs when running, (!!!), to make sure no air leaks

As they say it is either fuel or electrics.........try to eliminate fuel completely

Trying to think of things that you have not listed
Earths?
Cables - choke and throttle?
Have you tested the rotor and the other bit, (forgot the name!)
Diode Board - any burnt wires?
New fuel
a bit of Redex thru the system
Big Hammer!

Good luck

 

[BillN]

Typical . . .

I have just replaced the timing chain, which necessitated removing all the electrical gubbins from the front. It all went back together OK and the bike fired up fine when I finished the job.

did the problem start just after you did this or was the Bike OK for a few 100 miles?

Last evening I went to give the bike a run and fill the tank - but it wouldn't start. There was plenty of life in the battery, all lights work fine, starter was churning merrily - but not a sign of it firing.

Today its the same - no spark at the plugs but everything else OK.

Sometimes, especially in day light it can be difficult to see the spark or not - are you sure that there is one or not?

I had the 'bean can' apart last year and renewed the auto advance springs. It has been fine since, but I note that the three-pin plug and lead (which I didn't replace) is looking hard and old.

does the A/R bit still move OK when you take the front off the Bean Can


Bob.

Cheers

 

[Kenny]

Carbs etc clearly ok...so just a matter of ellimination ( he says !! )

Have you tried connecting the lower leads to the top plugs ( still earth the other original top ones out using the old spark plugs as they obviously won't reach the lower plugs. This will definately elliminate the coils as well if they don't start.
You've cleaned and double checked all electrical connections....so we are heading for a replacement bean can...in that case, I'll be eating your curry at the Wee Bash

Seriously...just go over things with an open mind...all mechanics are correct/ carbs are correct/ so something very minor or beancan.

Worth a quick call to St Eptoe

 

[bumpmuncher]

my vote is for the trigger wire breaking up (from the bean can) or a connector has pulled appart. good luck

 

[John Armstrong]

Some searching found this: http://maniac.deathstar.org/~flash/ig_trig.html

 

[MickDB1]

If yerve had front altenator cover off yer might have nicked the wire
I did

HTHY

 

[Rob Farmer]

Bob,

You shouldn't be able to measure anything between the terminals. The drawing below shows the connections for the unit:-

To test it put 12v dc on the 12V terminal. 0v on the ground and your multimeter set to DC volts on the signal wire (the common multimeter lead goes to the ground wire). turning the unit and it should switch between 0v and 0.6V.

The trigger is a transistor circuit and is simply switching across the transistor. If you have an LED and a resistor you can simply connect it between the 12V and the trigger. The LED will then switch on and off as you turn the unit. Great for setting your timing statically.

 

[Rob Farmer]

Just a thought. The under tank ignition unit usually fires everytime you turn the ignition on and off regardless of the state of beancan.

 

[Voyager]

Thanks folks - but the thing's stuffed


I spent the morning going through all the electrical connections (the loom is practically new and I didn't find anything).

I then carried out the tests as specified in the BMW and Haynes manuals . .


1. Test voltage supply at Control Unit, Terminals 2 & 4: 13.1 volts on both Unit and Battery, so OK.

2. Examine Voltage supply of ignition trigger, Control terminals 5 & 3. There must be a minimum of 5v : Volts = 12.2 V, so OK.

3. Withdraw terminal 5 from Control Unit connection. Test Milliamps between detachhed wire & terminal 4 (with Unit plugged in).

If current is between 3 & 20 mA - replace Control Unit.

If current is less than 3 or greater than 20 mA - Replace ignition trigger.

Current was 5.53 mA, and as Control Unit had passed the previous test, all should be well.


I then unplugged the Hall Sensor and connected a lead to the centre pin of the control lead.

With ignition on, I could get sparks at the plugs by earthing the centre pin.


After all that, I managed to get the bike to start.

After lunch it started again and I took it for a run, stopping at my local filling station (4 miles).

There was a bit of a mis-fire on the road and it wouldn't idle properly. When I stopped at the pumps it idled briefly then cut out.

It wouldn't start again, so . . . .

An ignominious ending.


I think there must be an intermittant fault in the electronics, so I'll no doubt end up replacing everything eventually


Next job is to strip the carbs and make sure they are properly clean - they are not totally free of suspicion at the moment.


Hey Ho - and I was looking forward to the Wee-Kend as well

I'll PM Proff and Crapaud with my apologies.


Bob.

 

[Fanum]

Hey Ho - and I was looking forward to the Wee-Kend as well

I'll PM Proff and Crapaud with my apologies.


Bob.

Shame to miss the event- why not just drag the thing down in that trailer?- if the collected airheads down at Sid's can't fix it, I'd be very very surprised.

For an old fart, that Proff bloke seems to know a little about a few things

 

[brassmonkey001]

All is not lost.

If yerve had front altenator cover off yer might have nicked the wire
I did

HTHY

Oh good, I'm not the first then.


Bob - I'm sorry you're having troubles. I wonder if it's a break in a wire somewhere or a connector pin backed out? These can be buggers to track down.


Here's a thought. If you can get it running again, why not ride it as far as you can towards Devon and if it breaks down get the AA to carry it the rest of the way? I'm sure someone will be able to fix it down there and it would make a good learning exercise for those whose knowledge of tracing electrical gremlins is not so good.

Edit: Fanny beat me to it.

 

[BillN]

Trailer it down and put together a "workshop" as part of the weekend

Plenty of Airheads there to swop parts with to find out if any electrical bits are duff

You should then get it fixed for free

 

[Voyager]

Bob - I'm sorry you're having troubles. I wonder if it's a break in a wire somewhere or a connector pin backed out? These can be buggers to track down.

I suspect its a break in the Bean Can wiring as that is well past its best (and has probably been trapped by the alternator cover at some point in the past ).

I'll stick with it as I want to find the cause - not just replace bits until it starts working again.

Its not that difficult to fix, but tracing an intermittant fault is very time consuming.

I take it you're going Have a great time and post lots of pictures


Bob.

 

[Stumpy]

Bob

If you want to stick it in the back of my van and drive that down for the weekend you're more than welcome. May prove a better run down than towing a trailer. I'm off to GOTC so the van will just be sat here

Stumpy

 

[Decster]

You might have to change your sig line to 'R100GS Unstartable'....

 

[Voyager]

You might have to change your sig line to 'R100GS Unstartable'....

Yes . . .

Its not just the brakes that don't work


Bob.

 

[Voyager]

Bob

If you want to stick it in the back of my van and drive that down for the weekend you're more than welcome. May prove a better run down than towing a trailer. I'm off to GOTC so the van will just be sat here

Stumpy

Thanks for the offer, Andy.

I'll work on it at home. I'm not stuck for ideas - just time. But that ceases to be a problem if I call off.

Besides, I'd just be jealous of those with working bikes.


Bob.