Ammeter adjustment

Started by Tigerfeet, 04 Mar, 2026, 14:29

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Tigerfeet

My new Lucas 8 amp ammeter needle flops to +3 amps when installed in the C15 nacelle - which isn't flat - and then reads plus or minus from that position.

If I take the ammeter back out of the bike, and hold it at an angle the other way the needle moves back to the proper zero.

The needle rear end seems to rest on a grub screw in the back of the case - but although this seems to be accessible through the back, it seems to have been drilled out (to prevent fiddling?). 

Does anyone know if this is an adjuster for the zero position, and if so what tool is required? Or do I just send it back and hope that the next one is better?

maddogmargetts@yahoo.co.u

Interesting conundrum. My first thought is the ammeter needle is faulty or it's not earthing. If it were me I would expect Lucas, The Prince of Darkness, to take it back and replace it with one that has not been tampered with. I mean why drill out an accessible entrance point? All British bikes are made to adjust and have access points, to tamper with it to stop adjustment is just not British ! There may be exceptions but I know of none, there are certainly some very awkward access points but can be done with the correct tool and bodily contortions.
john

rhyatt

Strange indeed.
So, if you remove it from the headlamp , hold it horizontally , the needle stays at the centre 0 point.
It's only when you lay it over the 10 degrees from horizontal and place in the C15 ammeter hole that the needle wavers away from 0.
The initial temptation is to return it.

limeyrob

Return it.  I can say that from bitter experience that all attempts to adjust are likely to end with a broken instrument that cannot be returned.  At the moment you have a faulty instrument that can be returned, it is however possible to spend 2 frustrating hours turning it into a faulty instrument that cannot be returned.

"Have to tried to adjust it.....?"
"noooooo....."
 :-\

V500

Quote from: maddogmargetts@yahoo.co.u on 04 Mar, 2026, 14:45 Lucas, The Prince of Darkness,

Oh no, not that old cliche again.
If the OP is thinking of returning it then it suggests that it's a modern repro rather than original Lucas, and no matter the colour of the packaging or the name on the box it's Taiwan stuff.
I had two fail and the seller wouldn't refund or replace (thanks Feked, you bunch of shysters) so I just had to accept that modern ammeters just aren't made very well.

Ted_Flash

Find an Indian made ammeter for Royal Enfields - they are generally good quality with damped needles and can be illuminated (quite useful in the dark)

rhyatt

I've gone over to one of these led colour changing things in the ammeter hole.
Use a blanking grommet with a hole for this led unit.

idie

The little screw under the ammeter is the needle pivot screw
 On a good ammeter tightning the screw acts as a damper. As already said if unit is new send it back.

Veloduke

Quote from: V500 on 04 Mar, 2026, 18:04 If the OP is thinking of returning it then it suggests that it's a modern repro rather than original Lucas, and no matter the colour of the packaging or the name on the box it's Taiwan stuff.
I had two fail and the seller wouldn't refund or replace (thanks Feked, you bunch of shysters) so I just had to accept that modern ammeters just aren't made very well.

Agree on both points.

Modern Lucas branded ammeters are of poor quality, I tried 2 that didn't work properly.

I won't buy anything from Feked anymore, they sent me the wrong size fork dust shields (I had ordered the correct ones) and they refused to accept they made a mistake despite photos, and wouldn't refund my money.

They should rename themselves to 'You're Feked'.
Cheers

Max

idie

I won't use them. I have had problems with the quality of things they sell. Their refusal of taking any responsibility for the poor quality.

scifi

Sounds like your Ammeter does not have any balancing of the meter movement.  Most movements have a blob of something ( lead.?) to counterbalance the weight of the needle.

One other possibility is that you have something magnetic in the nacelle...  Does the meter read incorrectly when held at that angle in mid air..?