'83 R 65 electrical problem?

[redzap]

Hi Gang,
This is my first post and I am an 11 year BMWMOA member. My problem is that my 83 R 65 with 16K miles on it quit running while I was riding and won't re-start. I changed the plugs and they are gapped correctly. This bike has an electronic ignition as you know. It is getting fuel and the battery is fully charged and somewhat new. Can you help me troubleshoot? Thanks!

[Bill Burke]

Let's start simple: The engine kill switch is in the ON position yes?

[boxermaf]

Does the starter crank the engine ?
If the starter cranks/engine turns, do you get any "fire" at all ?
If not sure, an easy way to check the ignition is to unscrew
the sparkplugs, connect them to the spark plug wires again, but
leave the plugs resting on the cylinders (to ground them). you might
want to use a large elastic or something to tie/hold the sparkplugs
onto the cylinders so they don't fall off while cranking. In a dim/darkened garage, you *should* see a good bright spark from
each plug as the engine tries to start. If you're not getting it, then
we can dive into all the bits that create the spark. Don't try
to start the engine without the plugs connected and grounded or
you might cause damage to other ignition components.

[lkchris]

If this bike has only one igntion coil, it may have failed.

[redzap]

Yes, Bill, the kill switch is in the "on" position. The starter does crank the engine but I will check the spark as instructed. If it is the coil, how can I be sure before I have to purchase another?

[Bill Burke]

Good job. So your kill switch is not involved, your battery cranks the engine so your ground wire is not disconnected. Now check for spark in the manner described by Boxermaf above (be sure to keep the plug grounded to the jug as you hit the start button - use a bungee to secure the base of the plug to the jug or you can damage the electronic ignition). Report results back here.

If you have spark, we can take it from there.

If no spark, then here's some insight into the direction we're headed (from a 2004 post by John Thompson in the Airhead archives):

Obviously from the areas you've looked at already, the remaining two
suspects would be the ignition control unit under the tank on the frame, and the ignition trigger at the front of the engine under the front cover. If
both plugs fail to fire when it's acting up, the coil would be the only
other suspect and the Dyna's are pretty reliable. Check all the connections
at the coil, control unit, and trigger also. It's fairly easy to swap out
parts for the trigger and control unit one at a time to see which of these
might be bad, and if you have another airhead of the 1981 and later vintage, these parts are the same. The control unit needs the back coated with the heat sink paste to work right, and if you don't have any, go to a radio shack or similar store and buy a small tube which will be a lifetime supply. I've had good service from Rick @ Motorad Electrik to get a rebuilt trigger or a new control unit if you find either of these parts as the culprit.

[redzap]

I checked the plugs for spark and there was no spark. Help! :dunno I will check the connections (again) and I'd be interested in reading the Johnson article; is it in the archives of this site or the Airheads Club? THANKS!

[Bill Burke]

Good. You're making progress. Now read this thread from the R65 forum. All three pages of it.

http://suraklyn.com/yabb/YaBB.pl?num=1178337700

[37071]

That thread that Bill gave us the link to is most helpful. My 86 R80G/S quit in the rain and then worked perfectly again as soon as it dried. It doesn't start as readily now as I rememeber it doing in the past. When I am in West Bend, I will pick a Dyna coil.
My 79 R65 has 2 coils. The bracket on one broke, and the lights quit due to no ground. Once the tank is off the problem was obvious and easily repaired.
:D