Boxerworks.com

chasbmw wrote:90% of airhead electrical problems are down to poor connections at the starter relay.

Could indeed be. There are two 81-84 RS electrical gremlin threads going. One here and the other on adv.
The adv RS cuts out when the charge light comes on. It's proving a tough one to diagnose.

This thread's RS has spark. Are the sparks blue or orange?

Re-reading posts helps, I see lots of recent electrical upgrades to the bike. That complicates things.

I had a similar experience recently - rough road, bike started miss-firing, running on one cylinder, intermittently on two but hard to tell exactly. One of the plug leads had lost good contact with the cap. The road side fix was cut a half inch off the end of the lead, re-thread into the cap. Good luck.

Hey everyone, thanks so much for your input. After testing all components and getting readings that were in spec, I decided to clean all ground and wiring connections directly associated with ignition issues. I cleaned battery grounds, coil grounds and the jumper wire between, and the wires at the ignition switch. After doing all that the bike has run smoother than ever and I have no more tach issues.

I'd been spoiled by having another 30+ year old bike that had been in a garage most of its life. This one has definitely seen some weather and while it looks good, its internals needed some refreshing.

Thanks for the help. I was able to get her out for some fun riding in the Texas hill country this past weekend. My first airhead, and I'm loving it as much as I thought I would. Especially burning up my buddies on their late-model Bonnies.