I missed the MAG Hands off EU ride this Sunday because I had to troubleshoot a problem with the bike and I'm very pissed off about it.
Took the week off to rest and do some work around the house and on the bike. The main thing I did was to sort out my valve clearances. All the exhaust valves were too tight, one had no clearance at all. They are all in spec now. Put the bike back together and it ran fine the Saturday night, started it Sunday morning and it was running on 1 cylinder intermittently. The problem seems to be only with the rear cylinder. I've previously had the bike stuttering and running on 1 cylinder for a few seconds at a time, but this is much more permanent and it stutters almost all the time. It certainly makes filtering on the M40 and A404 interesting...
I've previously tested the coils as per the manual and they tested in spec, but I must say I'm not too confident in a simple test like that. I cut the tip off each coil lead and screwed the spark suppressor caps back in to them to make sure the connection is good. I also swapped the front and rear caps around, the problem stays with the rear cylinder. The way I know it stays with the rear is by unplugging the rear spark plug lead when the bike idles on one cylinder, it just keeps running without change. If I unplug the front it dies. The rear lead sparks and I can't see/hear any breaks in this at idle. I've changed the plugs before when I had the stutter previously.
I've also opened the valve covers again and made sure the timing is correct. I did this because I thought I might have accidentally set the rear cylinder to spark on the exhaust stroke rather than the compression stroke, but it was correct. The problem is intermittent and if it works the bike runs well which is another indication that the timing is correct.
I've checked all connections as best as I could, but I didn't test every wire involved. I'm looking for some pointers on what to check. I'm wondering if it's perhaps an injector or an injector wire so I've dug out the testing procedure for that and will do it this weekend (I don't have proper tools to work on it where I stay in the week.)
It completely slipped my mind to swap the coils around, I will do that when I get home tonight. If the problem moves to the front cylinder I will know it's a coil issue. I'm hoping that it's something as simple as that.
Any help/suggestions would be appreciated at this point.