HOT main fuse and subsequently red connector,
Posted: Tue Oct 18, 2016 6:54 pm
Hi all,
I've been helping my neighbor work on his 79 CBX the last few weeks. He's an older gentleman, member of the CBX club from the 80s to early 2000s, but currently in poor health and with limited income. The bike is gorgeous and has been sitting in his shed, covered, but unridden for years. He would like to sell it so I told him I'd help him get it ready. It wouldn't start, but we rebuilt the carbs and it started like a champ....sounded so good. I noticed some smoke from the right side of bike and shut it down. The red/red white wires from the main fuse were melting. Connector melted as well. Due to amount of damage, I think this wire and connector were melted before we started after carb rebuild. I replaced the wires and the fuse assembly and gave it a test.
At this point, it will get hot with ignition on and kill switch on. Alternator and R/RR unplugged. Bike not running. With coils connected and headlight connected, fuse noticeably get hot. If either the coils or the headlight is disconnected, the fuse will get warm, but not hot. Over time, the red wires near red connector will begin to heat up as well. I have yet to let it heat up the point of melting insulation again.
What I've done:
-replaced Main fuse assemply and spliced a good red connector from an old harness he had into the bike harness(he has a great deal of parts, many in new OEM bags and boxes)
-Cleaned all spade and female connectors on harness, plus contact cleaner
-unplugged R/RR and Alternator out of circuit
-verified coils(Dynos) ohm'd out right
-Jumped coils strait from fuse, bypassing wiring trunk
-Checked ground near starter
-reran ground from coils mounting block
-tried old stock coils (actually got hotter, quicker)
-tried an old kill switch
-tried a different R/RR(before I noticed it will heat even if not connected)
-checked voltage drop from fuse to coils(I spent a lot of time looking in that area since it seemed to heat up most when connected)....just a few mV drop
I plan to use my other VM that can do DC current and see if I can see what kind of draws I'm getting from various components.
Anyway, I'm kind at wits end. I know theory and troubleshoot pretty well, but this gremlin is really kicking my tail. At least I've gotten quite good with the CBX schematic.
Any other tips or things I should look at/consider from your CBX experienced types? One post I saw that was nearly identical ended up being a corroded alternator plug. Definitely not the case here.
Appreciate the help,
John
I've been helping my neighbor work on his 79 CBX the last few weeks. He's an older gentleman, member of the CBX club from the 80s to early 2000s, but currently in poor health and with limited income. The bike is gorgeous and has been sitting in his shed, covered, but unridden for years. He would like to sell it so I told him I'd help him get it ready. It wouldn't start, but we rebuilt the carbs and it started like a champ....sounded so good. I noticed some smoke from the right side of bike and shut it down. The red/red white wires from the main fuse were melting. Connector melted as well. Due to amount of damage, I think this wire and connector were melted before we started after carb rebuild. I replaced the wires and the fuse assembly and gave it a test.
At this point, it will get hot with ignition on and kill switch on. Alternator and R/RR unplugged. Bike not running. With coils connected and headlight connected, fuse noticeably get hot. If either the coils or the headlight is disconnected, the fuse will get warm, but not hot. Over time, the red wires near red connector will begin to heat up as well. I have yet to let it heat up the point of melting insulation again.
What I've done:
-replaced Main fuse assemply and spliced a good red connector from an old harness he had into the bike harness(he has a great deal of parts, many in new OEM bags and boxes)
-Cleaned all spade and female connectors on harness, plus contact cleaner
-unplugged R/RR and Alternator out of circuit
-verified coils(Dynos) ohm'd out right
-Jumped coils strait from fuse, bypassing wiring trunk
-Checked ground near starter
-reran ground from coils mounting block
-tried old stock coils (actually got hotter, quicker)
-tried an old kill switch
-tried a different R/RR(before I noticed it will heat even if not connected)
-checked voltage drop from fuse to coils(I spent a lot of time looking in that area since it seemed to heat up most when connected)....just a few mV drop
I plan to use my other VM that can do DC current and see if I can see what kind of draws I'm getting from various components.
Anyway, I'm kind at wits end. I know theory and troubleshoot pretty well, but this gremlin is really kicking my tail. At least I've gotten quite good with the CBX schematic.
Any other tips or things I should look at/consider from your CBX experienced types? One post I saw that was nearly identical ended up being a corroded alternator plug. Definitely not the case here.
Appreciate the help,
John