Check your 30A fuse on your 1100

[BudC]

Especially if it's a 91. (BTW, mine has the 40 alternator in it, which turns out to be irrelevant)

Tried to start the bike ( still not riding, but I needed to move it) and... dead.

Symptoms. Turn on key. Nothing. Actually, something: the clock blanks out. Check battery voltage. Looks good- 12.7 with key off and key on. Check at fuses. Voltage at bottom (clock) fuse: 12.7V key off, 1.6 V with key on.

Ok. High resistance somewhere in the circuit before the clock fuse. Maybe the ignition switch. Remove the air cleaner to get at it, pull the connector to the ignition switch. Made up a little bypass (wire with two male blade connectors on each end) and plugged it into the connector, simulating the ignition switch. Same symptom. Not the ignition switch (whew!).

Poke around in wiring, pulled the starter relay connector, fuse looks ok, but I'll pull it to make sure that it hasn't developed high resistance. Hmmm. It doesn't want to come out. Ok, get a big pair of needle nose and pull. 2/3rds of a fuse comes out. Part of blade remains in.

Picture attached. The blade to receptacle on one side of the fuse corroded and started melting both the fuse and the plastic around the female connector. Have a new starter relay assembly on order from David Silver. That should fix it.

After this, I looked around to see if this was a common problem. Evidently not, but I did find a similar thread here: https://www.st-owners.com/forums/threads/steeds-gone-dark.56146/#post-628124

So, after 37 years (I'm pretty sure I've never replaced that fuse - probably never even looked at it), Father Time decided to mess with me.

Check that fuse - pull the starter relay connector to get at it - pull it out, clean it (a little steel wool) and spray contact cleaner in the connector. Smear some dielectric grease on the blades and shove it back in. Save yourself $60.05.

 

[John OoSTerhuis]

Hi Bud. Glad you found it.

BTW, my 91 only turns 28 next month according to the VIN plate.

Regards, John

 

[Upt' North]

Likewise, never had to look at it, but will put it on the list of winter jobs.
Ta very much.
Upt'North.

 

[Oldbikefixr]

This area of wiring should get regular inspection.....no matter what the bike.

 

[Christianncg]

The 4 pin connector has been baking on my bike for quite some time. I have been meaning to bypass it along with the fuse since half of the pin connector is missing (40A alternator) but haven't got around to it. I guess this morning will have to do.

 

[Upt' North]

Hi Bud. Glad you found it.

BTW, my 91 only turns 28 next month according to the VIN plate.

Regards, John

I was thinking mine was getting old it's twenty this Autumn, it's just a baby.
Upt'North.
Now you've got me thinking, not recommended!
The oldest bike I've owned and ridden was a 30 year old CB750f2, but that was well and truly pampered, picture already posted in Photo's below. Didn't check the connections on that either but like I said it was a sunny day bike.

 

[CYYJ]

Hello Bud:

It is possible that the melted fuse you discovered is symptomatic of another, larger problem, which is melting of wires in the connector that fits into that relay. This is a well-known problem amongst ST 1100 motos, and the fix for the problem is known as the Red Wire Bypass.

That exact problem left me stuck at the side of the road in Belgium last month - see my post here: Stuck in Bastogne ST1100 Total Electrical Failure.

So, if you have the side cover off and are looking at that fuse, take a close look at the red connector block on top of the relay for signs of melting. Below is a picture of what my relay looked like when it failed.

Michael

 

[bdalameda]

I would call the Red Wire Bypass a required modification now that these bikes are aging and this is such a common failure mode. A simple modification to make than all ST1100 owners should do.

 

[red one]

It ain't just old bikes. Had to take my ride to the dealer when it was 3 months old. Keep smelling burnt electrical smell. Had to replace the whole fuseable 30 amp harness assembly under warranty.

 

[Christianncg]

I removed the fuse assembly/ connector plug away from the starter relay, and attached some weather proof spade connectors to the starter relay spades this morning. My connector was toasted about an inch away from the plastic, despite not having a 28 amp alternator anymore. Disassembly of the fused spades revealed corrosion inside the plastic cover, not visible from the outside in any way.

I also peeled back the wire up into the splice, about 3 inches of tape to pull back. The splice was kind of cooked too. Solder and some good heat shrink saved the day.

Haven't tested the new connection yet because I drained my battery leaving the key in the ignition after going inside to rest.

 

[CYYJ]

Bud:

See also this discussion, which is about the exact same problem you are having: Red Ignition Wire Bypass Failure . In particular, have a look at the photo in the first post - it is almost exactly the same as the picture you posted above.

Michael

 

[ST Gui]

Bud— did you test that fuse? It's tough to be certain from your pic but it almost looks as though the internal link is still good.

It looks like the connection at the fuse block probably had some corrosion increasing resistance between it and the fuse. The heat damaged the connection and the fuse but doesn't look like it blew the fuse.

So at the very least checking and cleaning connections on some regular basis might prevent that particular problem.

 

[Ron]

Usually the fuse doesn't blow. The red wire bypass is a $10/10 minute fix (depending on your familiarity of the ST).

 

[BudC]

I didn't bother testing the fuse, but I'm sure that the fuse element didn't blow. The failure was quite simple: the fuse to connector contact corroded, the increased resistance heated the connection until the plastic around it deformed enough to put stress on the mechanical connection and it opened up.

Actually, the red connector in front of the fuse, going to the starter relay, is fine, and the connections show no signs of corrosion, which is what causes the melting in the picure. If the blade to female connector surface becomes corroded, the resistance through that connection increases from milliohms to ohms, the temperature goes up from, essentially, resistive heating. The connection becomes equivalent to your heated vest, or seat, or grips. Hot enough, and it melts the plastic holding the actual contacts - the melted red connector. The same mechanism that caused my fuse failure.

I've cleaned those contacts and I will be using dielectric grease on them as well. I figure that Honda did their homework on those connectors, and as long as I don't let them degrade via corrosion, there should be no problem. It's lasted... hmmm... in November, it'll be 28 years, so I'm pretty sure it'll be ok. The only failure mechanism I can think of outside of corrosion, is metal fatigue resulting in insufficient pressure at the contact point. I looked at the female connector, which looks like Beryllium copper to me. In a previous life, I designed telephone relay contacts, and BeCu contacts have operational histories of 50-75 years. I'm not going to worry.

Seriously, if it ain't broke, don't fix it. Regular cleaning and dielectric grease should keep those connection operations for another 30 years. OTOH, it it already shows signs of overheating, then, yes, replace the connector... then keep the new one clean.

 

[ST Gui]

The failure was quite simple

and somewhat common too in some bikes more than others.