Ian(https://miles-by-motorcycle.com/ian) , so I've had this intermittent ignition problem for years on end where one of my coils would drop out, the bike would only fire on two cylinders and the tach would drop to 0. Historically, this has happened at a frequency of about once every two years or so. Recently, it's happened more often. On the Blue Ridge trip with AGrip(https://miles-by-motorcycle.com/252) it happened daily. I have suspected that it might be the "output stage" otherwise known as the "ignition control module" for some time because reseating the connector, or even just pressing on it, makes the symptoms appear to vanish. So on Saturday as an experiment, I replaced the ignition control module with a spare I bought some years ago, lost and then refound recently. Strangely, the bike immediately felt completely different. It started up with more authority, idled much more smoothly and overall felt completely different. This was encouraging. I took it on a 200+ mile ride on Sunday and the problem I had been experiencing daily did not recur. However, the bike started running hot. Additionally, my fuel economy went through the roof. (I haven't measured the whole tank but I bet I'm getting close to 60mpg.) Also, the other riders reported that they did not see any of the characteristic black smoke out of the exhaust and did not smell any of the rich exhaust fumes my bike is known for. Based on all on all of this, and some discussions with the others, we suspect the old ignition control module has been intermittently faulty for some years and this replacement is now causing cylinders 1 & 2 to fire correctly causing the mixture to be leaned out. (My bike has no oxygen sensor so can't adjust itself.) So I'm going to take it into Bob's tomorrow to have the mixture checked/adjusted to see if my hypothesis is correct ...