[mrunderhill1975a]

Riding home last night, ammeter pegged in negative zone,, then hit a bump, then ammeter pegged in positive zone, lights went out, got about 1/4 mile and engine died.  I thought it was regulator/rectifier, but I replaced reg/rec still dead.  The battery dropped to about 12 volts. Charged it up to 13 this morning but now no power to anything.  Anyone have this problem? I assume there is a dead short somewhere. I looked for melted wires, haven't found any yet.  Has anyone had a ammeter fail by itself?

[Arizoni]

I suppose you might have burned out the ammeter but I think the first thing I would look for is a blown fuse.

If you want to test your ammeter, disconnect one or both of the wires that power it (not the light bulb) and check the resistance between the terminals.

It should be almost zero ohms of resistance.  If you don't get any reading at all, it's dead.

[mrunderhill1975a]

Thanks for the comment.  I started working on the problem last evening until the sun went down. I did check for blown fuse, the fuse was still intact although it had some discoloration as if it was under stress and near melting.

I traced the positive wire from the battery to the ignition switch.  I had power to switch, but no power out of the switch. The two red wire connections on the switch looked a bit burned. I am suspect of a dead short in the switch itself.  So, I have a new switch on order.  I will test ammeter per you suggestion tonight.

I removed the switch from the bike easily, however, there is a chrome switch plate that surrounds the switch and I would like to remove that plate.  Do you know if the switch plate screws into the nacelle or is it a press fit?  Any suggestions on how to free up that plate without cracking the nacelle?

[Adrian II]

It has a serrated edge and is a press fit into the ally casquette (it's in the hole where the old-style main light switch used to fit). You can knock it out from inside the casquette, use a hot-air gun to warm up and expand the ally if necessary.

A.

[mrunderhill1975a]

Thanks for the info, I will try to heat it up, then tap it out.

After searching through the files for a long time today, I found this thread with more info:

https://forum.classicmotorworks.com/index.php/topic,24837.msg285898.html#msg285898

[mrunderhill1975a]

Update:

I checked the resistance in the ammeter last night per your instructions, and the ammeter is fine.
However, the melted ignition switch seems to be a symptom of the problem rather than the cause.  Today I bypassed the ignition switch with a jumper wire, and the jumper wire immediately melted.  I will now follow the red wire from the switch to the ammeter and see if I can find a short somewhere.

A side note, I found one wire from the alternator has melted and become detached.

[mrunderhill1975a]

I worked on the bike last night for an hour or so.  I found the grey wires (to the trafficators/turn signal) were partially melted.  Also found the orange wire from the alternator had at least two places where the solder joints melted and detached the connection. I think these are just symptoms, I will continue unwrap the wire bundle and see if I can find the main short.

[mrunderhill1975a]

Update:
I worked about 8 hrs this weekend and finally found the problem.  In the Nacelle, the grey/black trace wire was melted where it connected to red/white trace wire.  The grey/black trace wire connects to the grey wire that runs the length of the bike back to the taillight.  I had to remove the tank and slit open the main harness following the melted grey wire. At various points in the harness the grey wire had melted with the purple and amber alternator wire to the rectifier and headlight.  I finally got into the taillight housing and one of the blade connectors must have worn through the insulation and made a dead short.  The melting wires then caused connection with alternator wires (probably explains the wild ammeter fluctuations).  Why did the fuse not blow when this short was melting wires you ask?

After looking closely at the fuse, I observed that someone had replaced the 15 amp fuse with a 30 amp fuse.  Who could have done that?  Since I am the only person that has worked on this bike, I can't blame Pete Snidal.  I'm guessing that I must have purchased a box of assorted fuses rather than the box with only 15 amp version and mistakenly put in a 30 amp.

The lesson for me is put the proper fuse in to save yourself the trouble of running new wire to replace the melted one.

[Arizoni]

Happy to hear you found the problem.
Unhappy to hear the gray wire caused so much damage to the rest of the wires in the harness. 

[Dhastings1954]

So your post made me think and I looked at my fuse. It is also a 30 amp fuse! That is what was on the bike when I bought it. It is supposed to be a 15 amp fuse?
Mine is a 1998 Bullet 500.

[mrunderhill1975a]

The wireing diagram for my June 1999 kick start Bullet 500 shows a 15 amp fuse.

I would suspect newer models or electric start would have a higher rated fuse. See if you can find the wiring diagram or owner manual for your bike to see what yours should use.

For my bike, at least, the wire will melt before the fuse with a 30 amp fuse.

I have attached two wire diagrams for the Bullets I own, one for USA 1999 Bullet and one for the USA 2004 electric start Bullet. The 2004 wiring diagram calls for a 20 amp fuse.

[Arizoni]

I have several Royal Enfield wiring diagrams I've downloaded over the years.

Several show a 20 amp main fuse and one of them shows a 15 amp main fuse.

No 30 amp fuses anywhere in sight.