Ignition problems? Stranded in France! Help!

[Vincent]

Hi,
Finally took my R65GS to France. It was running beautifully, but 50kms from Dieppe big exhaust Bang! complete power cut, the engine stopped. I turned it on again, power was back instantly but the engine wouldn't start. I let it cool down and it started again but sounded like it was running on one cylinder. Took it to BMW mechanic in Rouen. They checked cleaned adjusted the carburetors, spark plugs, checked valve clearances and compression. All good. They tried it again, never ran so well but after a while same problem, Bang! Power cut. They checked spark plugs and no spark, then, when cool, very feeble spark on both side (my HT leads are new). They told me that it could be the contact breaker...BMW hourly rate has seriously shortened my holydays already and I couldn't possibly leave it to them to sort out. I'm stranted. Has anybody out there had the same problem? Could somebody talk me through what to do to identify the causes of the prob? It must be something wrong with the ignition, isn't it?... What about ignition timing?
I've got plenty of time, the Haynes, the tools, a motorcycle breaker yard not too far but just don't know where to start.
The newby needs some more of that UKGSERs'wisdom.
Many thanks
Vincent

 

[bumpmuncher]

bad luck got one of the newer ones cant realy tell you much about your system, but i used to have an old vw camper and had a similar problem. every thing seemed spot on. i eventualy found that it was the wire on the points (contact breaker), it had broken inside the insulation and when it got hot the insulation softended and allowed the wire to part just enough to stop it working. hope you get it sorted and it dont shorten your trip any more good luck. Bm

 

[Sylvester]

I had a similar problem with a R100 gs and it turned out to be a cracked ignition coil. One minute it was running fine and then pop followed by nowt. Checked everything else and all was good. Changed the coil and service returned to normal. Have a look round for cracks etc on the coil.

 

[Vincent]

That will get me started...THANKS!
I''ll have a look at the coil and contact breaker tomorrow.
Any risks of electric shock??
Well, I'll let you know...
Cheers
Vince

 

[Deleted member CB]

A good start will be to try & get hold of a NEW set of points & codenser, not second hand bits from the breakers, cheap parts new & the only way to know for sure that they are right.
Good luck.

 

[Steptoe]

What year is the bike ?

After 1981 they had electronic ignition.

Also depending on the year, some have twin coils and later have a single coil.

The early type of single coil is notorious for failing. It's grey bodied twin output.

 

[Kenny]

If you have a high mudguard fitted..I don't suppose you've played around with this ? Main wiringharness runs between this and the lower headstock...wire could be broken at this point

 

[Phil Thomas]

I too, would certainly suspect the coil if it is the grey double ended type. Mine also started to fail in France, but luckily managed to get me home, where it failed completely.

Best of luck,

Phil Thomas

 

[Rob Farmer]

Take the front cover off and make sure the bean can wiring isn't trapped under the case. I had this on one of mine. It took ages to trace, the bike cut out when it got hot but was ok when it cooled.

Check the plug in connector on the ignition unit. It sits under the fuel tank next to the voltage regulator, The connector is held in place with a thin wire clip. Check for corrosion and to make sure the connector is seating probably. I had similar problems on an 80GS I bought from a dodgy London geezer

If theres a car scrap yard about you can use the ignition module from any of the cars in this list http://www.mobiletron.com.tw/detail_main.asp?ID=835. Any coill from a japanese bike with twin outputs could be used to get you away. If the wirings all ok then the only other possibility is the bean can unit under the front engine case.

This is the Haynes manual wiring diagram for the 80G/s - essentially the same as yours.

If you have a multimeter or some means of checking for voltage. Make sure the green/blue wire that goes to the ignition module and coil has 12V on it when you turn the ignition and put the kill switch on - this is also the same green/blue that goes to the ignition coil. Check for 12v there with everything turned on.

Let us know how you get on.

 

[Vincent]

I've checked the coil, and it seems to be in good condition. No cracks. The bike is from 1991 and it's a black sealed one in a metal case. I've had a good look at all wires and connection under the tank and in the front engine case and everything seems to be OK. I'll try to put my hand on a multimeter today to check the voltage.
As Kenny mentioned earlier on, I had that problem with the wires going on top of the front mudguard into the head light case. It took me a while to notice but I had a micro power cut when turning the handle bars. It was the cable going from the key switch to the positive of the battery that was damaged. I replaced it before I left but it might have damaged something in the ignition...

Something else I've noticed and forgot to tell you about is that when the bike is warm and the bang!/power cut is about to happen, the engine keeps on reeving when I stop and takes a long time to come down to idle...Might be a clue what's wrong?
Thanks for your help, I won't give up.
I keep you posted
Cheers
Vince

 

[Deleted account 111026]

Hello Vince, I'm about 90 - 100 km north of you, near Hesdin, region Pas de Calais, can I be of any help?

 

[Graham W]

This revving could be caused by the mechanical advance/retard unit in the bean can sticking, and the weights not returning correctly at low revs. It won't cause your 'bang!/power cut' on its own but it could be a clue that the bean can isn't 100% - and the other components in there certainly can fail and cause your lack of sparks in the way you describe.

Something else I've noticed and forgot to tell you about is that when the bike is warm and the bang!/power cut is about to happen, the engine keeps on reeving when I stop and takes a long time to come down to idle...Might be a clue what's wrong?
Thanks for your help, I won't give up.
I keep you posted
Cheers
Vince

 

[shafted]

Check out the 3 pin socket that goes to the 'Hall Effect Sensor'. The live feed usually goes AWOL and the start of it doing so is intermitent ignition. This will cause a build up of petrol in the cylinder's, so that when you do have ignition you will get a BANG cause there's too much petrol in there (not good for valve life!).
Safe riding Karl.