Hitchcocks Forum

Hi all,

I have a 1955 Bullet 500cc with an approx 1990 Indian engine. Sometime in its past it has been rewired and doesn't resemble any of the wiring diagrammes I can find. Obviously I don't have quite a few parts which are on more modern Bullets (no indicators, no full/dip lights on the speedo etc. etc). Since I've had it the ammeter has never worked. I replaced the ammeter wondering if this was the problem, but still nothing - well hardly anything - it does show a slight negative movement when I have all the lights on. It doesn't show the dip to the left as the engine is turned over before starting for example....

I've been trying to trace the wiring. There are only 2 connections on the ammeter. On one side I have 2 Br/Bl wires. One seems to go to one terminal of the horn and the other disappears into a loom and I can't trace where it goes at the moment. On the other side are 2 Br/Wh wires. One seems to go to the light switch and the other to the ignition switch....

So, does anyone have any idea what the wires should be connected to, and whether this seems to make any sense? I thought it may just be a bad earth, but everything SEEMS to be fine, everywhere I've checked.

Thanks in advance for any advice.

Sab: You said: "Sometime in its past, it has been rewired and doesn't resemble any of the wiring diagrams I can find" ....so for a remote hands off diagnosis it is going to very difficult without going through a lengthy 20 questions routine to find out what goes where. What I would suggest is that you remove all the wires from the ammeter then run a a new wire from the battery terminal via a 5 amp fuse from the battery LIVE terminal to any one side of the ammeter. Then only replace the disconnected wires one at a time on the other terminal. Make sure the needle swings to discharge when say the lights or ignition are operated. Keep the new battery wire all on its own on the ammeter. As you add back the remaining wires to the other terminal, you might well get a short and the fuse is most likely to blow. This wire will almost certainly be a wire that goes back to the battery and is likely to the main supply. This wire is the one that should now take the place of the new wire you have run, so disconnect the temporary wire and have the "shorting" wire take its place on its terminal. The remaining wires should all be on the other terminal to this one. You could of course hunt around with an ammeter to trace the original live wire with a voltmeter set to 12V or more (multimeter) but I don't if you have one. By the way if the live wire is twinned up with another wire don't worry as this is likely to the horn or maybe the stop light feed wire....no need to separate them, but don't expect them to show a reading when operated... Hopefully this will bring back the ammeter into circuit and should sort out the jumble.

"Make sure the needle swings to discharge when say the lights or ignition are operated".......EXTRA: IF AMMETER deflects to "CHARGE" change new wire onto other ammeter terminal so needle moves to DISCHARGE and then carry on with the instructions.

Hi Sab. Don't bother with that (lengthy instruction)....I have made a mistake...( TUT TUT must do better and put the beer down) )....I'm having dinner now so will ammend the instruction a bit later.

Ahhhhhh. Corrected my brain now. Now carry on just the same but whereas when, I said you would get a short, there will be one wire that you add that will casue the discharge deflection to become LESS when there is a load operating through the ammeter, this wire will be the wire be the the most likely to go back direct to the battery and so should be substituted for the temporary wire. IF by any chance you do have a multimeter or voltmeter, after you have removed the ammeter wires, you can search around for the live feed back to the battery and when you find it this has to be terminated on one side and the other "Load" wires on the other side of the ammeter. This in retrospect seems alot easier but as said before, I don't know if you have a meter to hand.....where's my dessert?

Do you really need an ammeter? A voltmeter will fit, and tell you more about the health of the electrical system and only needs a switched live and earth. I know some will say an ammeter is needed to tell you when the points open, but its just as easy to feel the end of the compression phase to find the same point. If you really want to keep the amps then you may need to rewire the bike to a known system, and that could be lots of work.

Thanks for all the advice. Yes I do have a multimeter, and will work my way through your suggestions as soon as I get another hour to spare. And Midge, perhaps in retrospect a voltmeter would have been more helpful, but I have an ammeter now and it seems silly to have it only for decorative purposes!

Quick update. I just pulled all 4 wires off the ammeter. Both sides are paired up on one connecter each. Putting my voltmeter (set to 20V) from the -ve battery terminal to the connector gives no reading on either pair of wires. However, when I switch the ignition on I get 12V on both sides! SO, next question... Should the 12V feed to the ammeter go through the ignition switch, or as you suggested Les, be direct from the battery with a 5A fuse? I'm wondering if this feed wire is missing and whether all 4 of the existing wires should be on the other side of the meter. Does that sound right?

Hi Sab. I am assuming from what you say your bike has negative earth? So with all the wires “floating” you get no voltage with the ignition off but then all wires show 12v with ignition on? So now next test would be to operate each system…lights/ignition/horn/stop light separately and see if they work without being connected to the ammeter. It seems somewhere on the wiring there is a cross connection between the live positive side and the wiring that should only/normally be energised through the ammeter. The 5 amp fuse was simply to ensure that no damage was done if you shorted out anything with the new extra temporary wire. I don’t think that a wire is missing as you do have voltage available at the ammeter….what is wrong is that you have battery voltage available at two positions and cancelling any current through the ammeter, in effect bypassing it. You only require just one wire (fused) from the live side of the battery so if you have two or more remove them. Usually you would have the ignition and lights power up through the ignition switch and have the horn separate (common set up). So now you need to find one wire that comes directly from the live battery terminal and have this on one side of the ammeter. On this same side you can have the horn wire. On the other ammeter terminal, you must have a wire that goes off to the ignition switch. Then on the other side of the ignition switch you will need a wire that goes to the lighting switch. Do not bring this back to the ammeter….it is connected only to the lighting switch. Then on the same side of the ammeter that goes to ignition switch you will also need a wire that is coming from the rectifier or control unit that is supplied from the alternator (I am assuming it does have an alternator) So you will also have to trace this wire out from the rect/regulator. After you have it connected in this manner the ammeter will register charging and discharging…AS LONG as there are no other cross-connections of the circuit somewhere else. The auxiliary wire I made mention of at first might be required to bypass some wiring but I’m afraid the only way is to prove each wire from one end to the other by disconnecting much of the wiring and testing continuity and make your own diagram Then reconnect it up in stages to achieve the connections as described earlier. It’s harder to describe than do really. Have a go at identification first and make a diagram, this will help no end. Then try to configure the wiring as described. See how you get on.

I meant to say your bike has positive earth...makes no difference of course.