Since moving house I've been forced to keep my FJ1100 outside under shading. Thus a lot of moisture & dust has become a problem. Was fine one day the next it fired on pistons 1 & 4 only. Inspecting and cleaning the loom connectors (those exposed to the weather) I eventually found which surely was the culprit (see attached). Since cleaning up and "tightening" the slide connector the bike has behaved. Strange problem I'm still having is that sporadically it'll start misfiring at idle and low revs. If I'm not quick enough to catch it the motor dies and then it's a mission getting it going again (similar to the engine flooding). Cleaned the plug leads and replaced the fairly new sparkplugs as well. I have since gone through all the connectors again but can't find anything as far as bad connectors are concerned. Any pointers please?
If it's misfiring on 1 & 4, I'd focus on the ignition coil for the those two cylinders and all of it's connectors, as a starting point and pop the tank off and check everything around the coil and the steering head.
It's unlikely to be the plugs or caps on only those two cylinders and I doubt it's coincidental that they both run off the same ignition coil.
Yep, as Dean mentioned, #1 & #4 share the same coil. Your system voltage is low at low revs, so that's when a misfire can occur, due to bad connections.
Also check the 2 coil pickups under the left side crank cover.
Good that you found and corrected the infamous "red plug"
https://fjowners.com/index.php?topic=19557.0
Gamut,
Good advice above. Check your coil grounds for corroded connections. In addition, you can feed the full battery Voltage to the coils with a relay. The ignition switch turns ON the relay, instead of the coils, and the relay sends the full battery voltage to the coils. Look for the Coil (Ignition) Relay Mod postings, here, for more info. Many riders do this mod with the stock bike. You should like the extra performance. Just a thought . . .
Quote from: Millietant on December 15, 2024, 06:20:57 AMIf it's misfiring on 1 & 4, I'd focus on the ignition coil for the those two cylinders and all of it's connectors, as a starting point and pop the tank off and check everything around the coil and the steering head.
It's unlikely to be the plugs or caps on only those two cylinders and I doubt it's coincidental that they both run off the same ignition coil.
1 and 4 are the only ones firing with 2 & 3 on AWOL. I have not gone as far as removing and cleaning around the coils as yet. Thanks for that one.
Quote from: Pat Conlon on December 15, 2024, 10:09:25 AMYep, as Dean mentioned, #1 & #4 share the same coil. Your system voltage is low at low revs, so that's when a misfire can occur, due to bad connections.
Also check the 2 coil pickups under the left side crank cover.
Good that you found and corrected the infamous "red plug"
https://fjowners.com/index.php?topic=19557.0
Thanks Pat. Wasn't aware of the pickups and will definitely check those out as well.
Quote from: red on December 15, 2024, 04:53:30 PMGamut,
Good advice above. Check your coil grounds for corroded connections. In addition, you can feed the full battery Voltage to the coils with a relay. The ignition switch turns ON the relay, instead of the coils, and the relay sends the full battery voltage to the coils. Look for the Coil (Ignition) Relay Mod postings, here, for more info. Many riders do this mod with the stock bike. You should like the extra performance. Just a thought . . .
Thanks Red - from your "you should like the extra performance" it sounds like something I'll have to look into. :good2:
Quick feedback on this issue - removed and checked both coils with connectors. First start-up and short ride it seems that issue is gone (for now). Just another question, are the HT leads removable from the coils? Thanks for all the input.