Britbike forum Forums British Motorcycle specific Brands Triumph bulletin board Fitting a dummy amp meter to a modern T100.

Hi guys as a not to the past I fancy fitting a round type ammeter to my modern-day T100 Bonneville.

Please dont laugh but not wired up just as a dummy.

But with the headlamp bowl being curved or rounded I fear it will not sit flat.

Could somebody tell me how this work on a 60s Bonnie with the Amp Meter fitted to the Headlamp bowl.

Did those early bowls have a flat section pressed into the bowl for the meter to sit flat on?

I have no intention of wiring it up its purely cosmetic.

Have a decal made up and stick to the shell.

They were only a dummy in the old triumphs and beezers anyway, after about 10 miles.
Useless pieces of garbage, all they indicated was how much the bike was vibrating.

The ammeter is small, the headlight is large, and the hole for the ammeter is just a hole: no "flat" area or depression to mount it.

The ammeter is supposed to have a thin rubber O-ring under it as a gasket, and this O-ring compensates for any difference between the shapes of the two.

Yeah but if they vibrate to the right it is charging and to the left for discharge.

All of mine have bounced from the + pin to the - pin at the speed of light.

The headlamp shells are roughly spherical at that point, so a 1.5" hole has a pretty flat surface.

Whether your modern T100 one is similar I wouldn't know.

Why wouldn't you wire it up? If you intend installing one surely a working one is that much better? Even if you wire up a battery monitor gauge instead, it would be useful.

"Why wouldn't you wire it up? If you intend installing one surely a working one is that much better? Even if you wire up a battery monitor gauge instead, it would be useful."

I think a decal or fake won't compromise reliability as a real one will!

Would not wire it up as the bike has a charge warning lamp fitted...

Also the bike has Can Bus electrics....I dont know enough about those systems and would not want to cause any problems.

On my old Classic BSA I fitted an LED charge warning lamp...shows one of 3 colors to show charge and bat volts on the move and when parked up....may consider one of those.

Very discrete.

I did the same on a bobber build. I used a rubber band around the ammeter case inside the headlight shell. Works like a charm

Thanks Scott you must think lie I do.

Did it sit unevenly on the lamp bowl? wonder how neat it looks...or does it let water inside the bowl.

Assuming that you’ll be using the smaller ammeter used in most British headlamps for many years, it requires a hole 1.625” dia (~41.3mm).

The bezel surface that actually sits on the shell is about 2-3mm wide, so OD ~ 45-47mm.

If you can find or make any flat washer, ring or bit of pipe with approximately these dimensions (the ID of ~1.625” is the important measure) then you will be able to place it on the headlamp shell and see how good a fit you get in various parts of its curvature.

Just bear in mind that things inside the shell may interfere with the depth of the ammeter body.
If this happens to be the case, you could fill the ammeter with clear resin (with the needle showing a charge haha?) and then shave the body more shallow.

Just thoughts.

Good idea I will try that.