Pilot lights - bulb options?

[Molly]

Good morning from the Isle of Man. Had a scout around through the FAQs but couldn't see the answer to this question. Apologies if I've overlooked it. 

I need to replace one of the pilot bulbs. eBay shows two options: R284 (2.3w) and R286 (1.2w). I was going to order the 2.3w bulbs but before I did I thought I'd ask if there's a preferred option? LED perhaps? 

Thanks in advance for your advice. 

Off to watch the bikes come through Kirk Michael. :-) 

 

 

Edited June 3 by Molly
typo

[MartyNZ]

The V11 Owner's manual shows pilot lights were originally 1.2W. The lamps in the back of the Speedo/Tacho are 2.2W.

@Kiwi_Roy wrote in some posts about LED substitutes for those incandescent lamps.

https://www.v11lemans.com/forums/topic/20578-problems-with-dash-lights/#findComment-235855

Note that the "low fuel" light must be an incandescent lamp because the function relies on current draw.

Note also that indicator warning lamp must not be an incandescent lamp if you want to fit LED flashers.

https://www.v11lemans.com/forums/topic/30710-signal-indicators/

LED turn signal conversion problem - Page 3 - Technical Topics - Moto Guzzi V11LeMans.com Forum

 

Edited June 7 by MartyNZ

[motortouring]

I like the oil warning lamp to be as high as possible. The lights on the early V11Sports are not bright at all, so in case of a oil warning, you could easily miss it. These lights are only on for a short while so I do not fear the overheating of the fileament. (Except for high beam)

Edit:

So 2,2 watts would not be a problem.

By the way, you can order those light per 10 for a much better price. 

Edited June 8 by motortouring

[Molly]

Thank you chaps. As always, your help is much appreciated. 

[Pressureangle]

I put LED bulbs in my '85 LeMans, tiny little devils- so lovely by day, but at night they're so bright as to be annoying. As I have this 2000 V11 Sport apart- the dash came disassembled too for some reason- I'll probably use LED for the temporary lamps (oil, turn, battery...is the battery warning bulb a ground on this bike?) and incandescent for the 'always on' lamps. 

[audiomick]

On 6/9/2025 at 6:50 PM, Pressureangle said:

...is the battery warning bulb a ground on this bike?

I think it must be. As far as I understand the wiring diagram, one side of the lamp sees 12V together with a couple of other warning lamps, and the other side sees a connector on the regulator. It won't be getting 12V from both sides, so the connector on the regulator must be a switch to ground. 

Edited June 11 by audiomick

[Lucky Phil]

15 hours ago, audiomick said:

I think it must be. As far as I understand the wiring diagramme, one side of the lamp sees 12V together with a couple of other warning lamps, and the other side sees a connector on the regulator. It won't be getting 12V from both sides, so the connector on the regulator must be a switch to ground. 

No it does see voltage from both sides and there are diodes involved. It's about the voltage balance between the battery voltage and the regulator output not just a simple earthing system.

Phil 

Edited June 10 by Lucky Phil

[audiomick]

1 hour ago, Lucky Phil said:

... It's about the voltage balance between the battery voltage and the regulator output not just a simple earthing system.

Ah, ok. Thanks.

Do you happen to know if there is an internal circuit diagram of the regulator somewhere? In the workshop book, or on the 'net somewhere?

[docc]

2 hours ago, audiomick said:

Ah, ok. Thanks.

Do you happen to know if there is an internal circuit diagram of the regulator somewhere? In the workshop book, or on the 'net somewhere?

Kiwi_Roy drew one up.

Find it in @Weegie's dropbox:

https://www.dropbox.com/scl/fo/no8adkie1sl6frnc2qmm8/ALzrUXsngCqMRtfMR1cXedE?rlkey=8x5byzd4ux3107610i22ig5v6&e=1&st=3xbx7rbu&dl=0

[audiomick]

On 6/9/2025 at 7:20 PM, audiomick said:

As far as I understand the wiring diagramme, one side of the lamp sees 12V together with a couple of other warning lamps, and the other side sees a connector on the regulator. It won't be getting 12V from both sides, so the connector on the regulator must be a switch to ground. 

 

On 6/10/2025 at 10:45 AM, Lucky Phil said:

No it does see voltage from both sides and there are diodes involved. It's about the voltage balance between the battery voltage and the regulator output not just a simple earthing system.

 

On 6/10/2025 at 3:15 PM, docc said:

Kiwi_Roy drew (a schematic of the regulator) up.

I had a look at @Kiwi_Roy 's schematic,

https://www.dropbox.com/scl/fo/no8adkie1sl6frnc2qmm8/AILzvXQf32OQOHQBG1LB-E8/Regulator Schematic - Basic.pdf?rlkey=8x5byzd4ux3107610i22ig5v6&e=1&dl=0

scratched my head a bit, and came to the following conclusions:

The alternator warning lamp connector on the regulator is indeed a switch to ground, but not a simple mechanical switch.

The warning lamp does not see 12V from both sides. It sees 12V, together with some other warning lamps, from one side, and the "not a simple mechanical switch" in the regulator on the other side.

As @Lucky Phil wrote, it is about voltage balance, and there are diodes involved.

The switch to ground in the regulator is a mosfet transistor. When the key is turned on, the reference voltage that the regulator sees to control the charging circuit also turns the mosfet on, thereby providing a path to ground through the warning lamp for the 12V the lamp is seeing from the other side, and the lamp comes on.

The alternator produces AC current, i.e. for half of the time it is producing negative voltage. This is exploited to turn the warning lamp off.

When the motor starts, and with it the alternator, some diodes bleed off the +12V that is holding the mosfet open, and the warning lamp on, into the negative part of the alternator cycle. The mosfet goes off, and the lamp goes out.

If the alternator stops working, the +12V that hold the mosfet open can't be bleed off anymore, the mosfet opens and the lamp comes on.

So, to sum it up and repeat myself, the warning lamp does indeed "just switch to earth", but the switch is controlled by a circuit that is controlled by whether the alternator is producing current or not. If the alternator is working, the switch stays off. If the alternator stops working, so long as the battery still has some volts in it, the switch turns on and the lamp comes on.

If the battery is already dead and the alternator stops working, the lamp wont go on. But then again, neither will the motor, so one would probably notice that there is a problem somewhere even without the lamp. 

Edited June 11 by audiomick

[docc]

I have had the battery light come on with a broken yellow alternator wire connection (failed alternator status) and also a loose positive charging connection to the battery (running the battery down).

In simple terms, then, if the battery voltage and the charging voltage are mismatched enough, the imbalance grounds the warning light.

[audiomick]

25 minutes ago, docc said:

In simple terms, then, if the battery voltage and the charging voltage are mismatched enough, the imbalance grounds the warning light.

As far as I understand it, yes, that's about it. 

EDIT: only in one direction: if the charging voltage is lower than the battery voltage.

As I see it, there is something akin to a feedback loop in there. As long as the alternator is producing more than the battery state, the mosfet that turns on the warning lamp will be off. If and when the alternator output is lower than the charge state of the battery, the lamp will go on.

Edited June 11 by audiomick

[docc]

Regarding the "Pilot lights - bulb options? "

The very early V11 Sport had a "flat" lens over the indicator lights which were very dim.

 Later (2002?), jeweled lenses were introduced making the wee bulbs much more visible.

Also, incandescent bulbs will "plate" the interior of the glass over time making the bulb dimmer, looking a darker grey-black. Simply renewing the little bulbs can make a significant difference.

 

[PJPR01]

All of the bulbs with the exception of the blinker (indicator) can be replaced with LED’s making them much brighter.  If you also add the jeweled cover the lights will be infinitely better than stock.