Fuel delivery verses ignition failure.

[Airbear]

Good that it all worked out, Steve. The last time I looked in to this thread it was heading towards the HES being the culprit. As it happens, DucatiPete's 1981 R80 G/S broke down on the way to my place on Friday with very similar symptoms to yours - ie, just stopped 3 or so times but would start up again after a while. I trailered him from Wodonga and Jeff came out as well to mull over pissabolities. Spark was the issue and a bit of googling turned this up ...

"1. To test coils and ignition module: Pull a spark plug, insert it back into the plug wire cap, and ground it securely on the cylinder jug. Turn the ignition key to ON. Place the kill switch in the RUN position. Now, watch the plug while flipping the kill switch on and off. You should get a spark as the switch is turned off. If you DO get a spark, this indicates that both your coils and your ignition module are functional and you can focus on the ignition sensor.

2. To test ignition sensor (bean can) under front cover: remove negative cable from battery, remove front cover to access bean can. Remove a spark plug and ground it to engine as in 1 above. Find the electrical wire that leads from the bean can upwards to connect with the main harness. Disconnect that connector by carefully removing a thin wire bail that holds the two halves of the connector together. Pull the plug apart. Using about a three inch length of thin wire, insert an end of the wire into the MIDDLE female hole of the three-hole connector that leads to the bike's harness (not the remaining half of the connector that's made up to the beancan). Connect negative ground to battery. Turn on ignition to bike. Place kill switch in Run position. Now, while the thin wire remains inserted in the middle female connector hole, strike the other end against the metal alternator cover as though you're striking a match. If, when you "strike the match" you also get a spark on the grounded spark plug, your hall effect sensor has failed."


To our thinking this is a very concise troubleshooting guide. Test 2 indicated that the bean can was faulty. We had an ICU, cable and bean can from Jeff's collection to play with. Pete swapped in the bean can and all is good. Just thought I'd put this out there for others similarly afflicted with these damned, new-fangled, pointless airheads.

[Ray from Indiana]

Charlie
Yes that is a good test path but unfortunately it isn't reliable for an intermittent HES fault. For an intermittent fault, if step 1 proves good you just pull out your spare bean can and try it.

[ME 109]

We had it nailed before going to the pub Charlie. It was either/either. and we had both, spare.

[SteveD]

When my HES was kaput and left me by the side of the road a few years back, I rang the local BM shop.
They asked what happens to the tacho needle when the ignition is turned on? I said "nuthin". They said HES! It should move just a tad.

[ME 109]

When my HES was kaput and left me by the side of the road a few years back, I rang the local BM shop.
They asked what happens to the tacho needle when the ignition is turned on? I said "nuthin". They said HES! It should move just a tad.

Very easy!