sudden failure

[Bill Conquest]

Hi. I was taking a day ride  last week when the bike suddenly quit on me as if the kill switch had been hit.. I was going about 55 & running well when it shut down, It was not a fuel issue and when I checked the spark at the plugs there didn't seem to be any.. checked the points & they looked o.k., took off the tank & checked the main ground which had already been rerouted & it was o.k., it has relatively new coils & wires & caps...after about 40 min. it started & got me home but ran roughly..where should I start looking? It's a '79 r65.

Thanks for any ideas,

Bill

[flybot]

Start with the battery first. Same happened to me and I had a loose positive. Since you checked the grounds, Id go to the switch next.

[montmil]

... the bike suddenly quit on me as if the kill switch had been hit.

That wanky kill switch has stranded many riders. Intermittent operations are not that rare.

Run a circuit check or bypass the switch as a test. I never touch the kill switch on any of my Airheads.

[Bob_Roller]

Did the starter work, but the engine wouldn't fire ??

[Luca]

If the battery or ground was the problem, you would have lost all electrical components when the bike died.  I too would suspect the killswitch, but I also find it odd that it would run rough once you got it going again.

I know you said the coil was relatively new, but what is it?  When my Bosch "crack o' matic" bit the bullet on a rainy day, it wouldn't run unless I kept the revs up.  Supposedly they aren't known for longevity.

I'm also thinking of stories I've heard of  car coils getting hot and then not wanting to work until they cool off

Perhaps somebody could chime in with a test procedure for you coil.

[Bob_Roller]

His '79 R65, should have 2 seperate coils, like the kind that were in auto use for decades .

About the only way to test the coils, would be to heat them up with a hair dryer, or heat gun on low and see if you get the failure with a hot coil .

[Dugald]

I have expereinced the same problem in 2 diferent forms. The kill switch was the culprit in the first instance. Bike died completely and there was no starter or any electrical activity apart from the headlight. I quickly deduced the kill switch and gave it a wiggle and away it went.
Second instance was over a long ride last week.. new coils and spark plugs and leads. This did a lot to cure indifferent starting and rough running, however in my enthusiasm in getting the thing running as well as possible, I started to check all of the connectors under the tank.There was the one 3 wire connetor that was completely crusted internall in white salts. Took quite a bit of levering to get it apart and cleaned up... Putting it back together I had lost spark completely... Lots of fiddling eventually got some action and it went well for another 300 kms and then suddenly died again .. same symptom... starter turned over allright but no ignition eveident. After fiddling witht he rogue connector again, it went. ... So I am about to attack the connector with a points file and some vinegar which apparantly will dissolve all the accumulated salts..Then will try some dielectric grease to seal and protect from further corrosion.
So my advice is check all your connections!

[Bill Conquest]

Thanks for the responses.Yes, Bob..the starter was fine but absolutely no firing from the engine...i fired up the bike today & it ran well for about 1 mile, then the same thing again..battery is fine & the starter fires up well but the engine just shuts down. I fiddled with the kill switch wires but that didn't have any effect..will check all wire connections & think about new coils.. any other ideas?

Thaqnks,  Bill

[Dugald]

Since writing my earlier comments to this thread, Ive pulled apart the connector in question... The 3 wire connector that links the ignition controller witht he coils. It is located under the tank and I was pretty amazed at the condition of the conductors inside the connector. They were completely covered in dense verdigris buildup that must have had a significant impact on the effectiveness of the connector once I had disturbed it. My bike had lived most of its life in a warm marine climate which has left its mark all over the bike with corrosopm and build up of gunk everywhere.  It took a lot of force to get that cionnector apart and until I was able to fully clean the contacts, just reconnecting it was bound to lead to poor contacts and th eloss of ignition.
Good luck!!

[Tony Smith]

...after about 40 min. it started & got me home but ran roughly..where should I start looking? It's a '79 r65.

My wife's 79 r65 did a very similar thing a couple of times in the 90s, I recall that it died without warning, but after a 10 or 15 minute "break" it would start up again, although when it did restart it ran well.
 
Anyway I chased a few blind alleys, including checking earths, kill switch etc and thought I had it beat - then about 6 months later it did it again. On a hunch I replaced the ignition switch, a step that would normally have been rather expensive to do on nothing more than a hunch, but at the time I had a spare R65 I was robbing for parts (it is the one I am rebuilding now) and in any event it has never stopped without apparent cause since so I am counting that one as a win. Wife used to have about 500g of assorted keys, ornaments and other crap on her key ring, (again on a hunch) I suggested she pare that down a tad to no more than 3 or 4 keys, the theory being that having 1/2 kilo of stuff bouncing around on the end of the key was unlikely to be doing good things for the switch.
 
Anyway, I am grateful for you reminding me of that little event as my rebuild is currently sporting what I now remember to be a probably defective ignition switch.

[montmil]

Bill, Your problem is looking more and more like a heat related issue.

Have you checked the heat sink paste on the ICU? If that paste material has hardened and or started flaking away, that could cause intermittent running. Radio Shack for a small tube of their heat sink paste.

Next best guess would be an issue with the coils and a heat related problem with one or both.

[Bob_Roller]

His bike has a points type ignition .

I'm very far removed from a vehicle with points type ignition, could a failed or failing condenser by the points be a possible cause ?

[Barry]

I'm very far removed from a vehicle with points type ignition, could a failed or failing condenser by the points be a possible cause ?  

Could be a faulty condensor although it would have to fail short circuit for there to be no spark at all.

If the condensor failed open circuit there would be excessive arcing at the points and a very weak spark.  

[montmil]

His bike has a points type ignition.

Rats. Foiled again.

[nhmaf]

Certainly could be a shorted condensor, though not a guarantee that this is the culprit.   I'd certainly have it out and test it - or simply replace it - to see if it makes a difference.

I have to tip my hat to our new member Dugald, who lives in what has got to be one of the most interesting-named towns we have represented in our international community!