I have a question for the bright sparks amongst you?

I have a question for the bright sparks amongst you if you’d oblige me.

The headlight on my old CBR1000FT was fab. One of the bulbs (H4) blew so I changed both whilst it was apart (clocks etc off). Halfords have 35w motorcycle bulbs but the ones that came out was 55/60(?). Halfords are were doing an “up to 90% brighter” 55/60w range buy one get one free. I fitted these, the headlight looks more white but less bright (less powerful). The amount of light these new bulbs emits looks noticeably less and the light penetration is far less too.

Is there likely to be a car/bike thing that is causing this (bike generator not powerful enough) or are these bulbs not as bright as those that came out? The dipped beam needs lowering, but allowing for the light not hitting the same point on the view ahead, there is still a huge difference. Anyone got any (sensible) advice before I take them back?



no, take them back.you can get 100/90 h4 bulbs, they would be brighter.:slight_smile:

You might melt your wiring loom though…

…or buy this


The bulbs should both be 55/60W. The 35/35W ones are used in older machines, small scooters, or sometimes in twin headlamp 250s and the like. Standard car bulbs are fine, but you will find the 35/35W in the Halfords bike section as only very ancient cars would use them.

Before fitting 100/90W bulbs I would make sure the bike’s generation system can put out enough watts at the same time as running a spark, brake light and indicators.

as above stick with the standard bulbs, the 100w will melt something along the way most prob the connector ontor the bulb first.

I have a look at the bulb that came out
I for one often run a higher power head light bulb , and I never had any problems but I do remove the rubber connector cover to improve cooling of the connector

I’ve upgraded 55W H4’s to Halfords 100W H4 rally bulbs …

Protected by 10 amp fuse the wiring and the plastic lenses both survived

100 watts divided by 12 volts = 8.3 amps

edit: I think I still have a boxed pair of Halfords 100w H4’s hiding in the garage, I’ll check when I get the Bonne’ out later.

Thanks for the input gang. The 2 x 55/60w bulbs are great. I refitted the one the had not blown plus the one I had bought from the Honda dealer. My query really was with regard the other bulbs being whiter but weaker. I didnt know whether car bulbs need more power.

The wattage is the power being used by the bulb, not the amount of light produced. There is no reason why two 50/55w bulbs of different brands will give the same light (that is why you see things advertised as “30% brighter” and the like). The bulb still uses 55 (or 50 on main beam) watts, but produces more light. A 100/90 watt bulb will use more than 50% more current than a 60/55 watt bulb and will be brighter, but not necessarily more than 50% brighter.

As pointed out above, 100 watt bulb at 12v pulls 8.3 amps. You have two of them, so that would be 16.6 amps. Not sure what the spark will be pulling, but I would guess somewhere between 5 and 8 amps. So you are up to somewhere between 21 and 25 amps. Brake light, indicators and CDI/ECU etc will take another 3 or 4 amps or so. You now have something like 23 to 29 amps being pulled from the system when waiting to turn which is likely the highest drain and lowest generator output. Most bikes have a 30 amp fuse to protect the loom. Fit something like loud horns, heated grips, a speaker system, and something will blow, hopefully the main fuse!

Obviously a bike with single headlamp and a 30amp fuse will have more leeway if a 100w bulb is fitted.

I post this cautionary stuff due to idiots on other forums always posting about why was it that every time they used their new high power multi-horn system the bike went black!

If you can find a copy of "ride"magazine, look in their “best buy” section which should include headlamp bulbs. (Strictly they are lamps not bulbs, you plant those, but who cares.)

From fallible memory, something not too cheap from Philips came out best. Whiter and brighter but with pretty standard wattage. I’ve got a pair of those fitted.

I can endorse these as pretty damned good.

Sharron youre such a girl, forget the bike and visit a hair salon. Were sure it will take yer mind off trivia.