lights flicker/dim

Ish · 7 Jan 2012 at 16:28

Hi

On a Honda CBR125R when reving the engine the headlights and green neutral light flicker/dim.

The battery is pretty new and charges up fine.

Whart else could cause this?

bluDawg · 7 Jan 2012 at 16:51

it could be the battery as that is what used to happen on my old 50cc

arctine · 7 Jan 2012 at 17:25

How extreme is it?

I ask because this always happens to some extent on most bikes though usually when you rev the engine, they get slightly brighter.

dave_beast · 7 Jan 2012 at 17:32

Stick a single HID kit in there, it won't dim on idle anymore.

Ish · 7 Jan 2012 at 18:41

bluDawg said:
it could be the battery as that is what used to happen on my old 50cc

It's a new battery

arctine said:
How extreme is it?

I ask because this always happens to some extent on most bikes though usually when you rev the engine, they get slightly brighter.

It's not just a flicker the headlights will go off for an instant

dave_beast said:
Stick a single HID kit in there, it won't dim on idle anymore.

It doesn't dim on idle, only when you rev it about 3k.

arctine · 7 Jan 2012 at 18:48

My guess would be the voltage regulator. Get a Haynes manual and ivestigate.

dave_beast · 7 Jan 2012 at 18:54

Ish said:
It doesn't dim on idle, only when you rev it about 3k.

With a HID it won't dim at all!

Draeger · 7 Jan 2012 at 19:10

arctine said:
My guess would be the voltage regulator. Get a Haynes manual and ivestigate.

This^^. It'll be your regulator / rectifier guaranteed. Classic symptoms of one on the way out. Do you have access to a Voltmeter?.

bloodiedathame · 7 Jan 2012 at 21:05

I just got me on of these from the States. Genuine Triumph ones are cack and twice the price.

http://www.amazon.com/Compu-Fire-Regulator-3-Phase-Charging-Systems/dp/B0035U7LRM

(You won't need one of these babys but do some research on aftermarket reg/rec kits).

Ish · 7 Jan 2012 at 23:31

I'm selling the bike as soon as I pass my DAS so I have ordered one from Ebay.

Thanks for the help.

wazza300 · 8 Jan 2012 at 00:39

did you check the wiring coming from alternator to regulator? sometimes they melt at the plastic connectors,esp if you try to start your bike by holding thumb on starter for long periods could be poor connection ,should be three wires yellow going to black either under seat or under tank

thumperslaw · 9 Jan 2012 at 12:34

Sounds like reg rec going. Honda have this on every bike across the range

Dogbreath · 9 Jan 2012 at 12:35

dave_beast said:
With a HID it won't dim at all!

It will probably completely cut out instead, like the one on my brothers CBR600. As well as completely blinding anyone in front.

Ish · 14 Jan 2012 at 19:12

I changed the rectifier and it made no difference.

I had some spare headlight bulbs so I swapped them over and the problem went away.

It's strange how the lights worked fine up to 5k rpm. Maybe it was a loose filament on one of the bulbs.

Anyway it's fixed now and while I was at it I replaced the dead fuel gauge bulb as well.

It was a good learning experience taking the front of the bike apart and bikes are much easier to work on than cars!