Hi.. i have assumed that if you want to use higher rated H4 bulbs in any of the usual 400s from Honda unless it was a uk model that you had to do the bulb mod to prevent it from burning out left switch.

I now have a new friend with a RVF400 who says he has not done this mod and uses H4 bulbs and reckons that the mod is pointless on his bike ( like my CBR) because it does not have a on/off anyway.. i admit it sounded reasonable.. what do you lot think?

The mod is NC30 only, your friend is correct.

Lol.. thanks magg. You know what i done this mod years ago on my R model 29 and because im not electrically minded i went with the thought it was the thing to do.

It was not until i got talking to my mate that i thought... you know what he is talking sense. I ain't going to burn a switch out.. as i aint got one.. so what have i actually done it for?

Live and learn.

If the bike has two relays already, you don't need to add one to use full-power H4 bulbs. The j-spec NC30 only had a hi-beam relay from the factory.

Ciao,

JZH

Yeah.. i suppose i was thinking i needed to protect the switch gear not just the on/ off switch which i have not got. One of those things that never crossed my mind at the time. I done the mod anyway.. good practice

Be careful - higher powered bulbs can damage your headlight lenses.

With regards the mod - I did a headlight wiring mod to my NC35. I ran a wire from the battery (via a fuse) to a relay and thence to the lights. I switched the relay using the original 12V feed for the headlights.

manicguitarist wrote: Fri Dec 14, 2018 9:34 am Be careful - higher powered bulbs can damage your headlight lenses.

With regards the mod - I did a headlight wiring mod to my NC35. I ran a wire from the battery (via a fuse) to a relay and thence to the lights. I switched the relay using the original 12V feed for the headlights.

I have not had any lens fogging so far and the mod i done was similar to yours but again i dont know if it was worth it.. dunno really i wish someone good with electrics could confirm it.

What are you trying to achieve, what wattage bulbs have you fitted. A history as I understand it, NC30 oem was 35/60W bulbs with a relay fitted for the higher wattage highbeam circuit. 35/60W bulbs were H4B, hard to find and expensive. NC30 lowbeam relay mod is so that H4 55/60W bulbs an be fitted without risking damaging the headlight ON/OFF switch. NC35 oem is 55/60W bulbs and no ON/OFF switch, hence no lowbeam relay. You can do the relay mod as described by manicguitarist to improve the effectiveness of the highbeam by reducing the lighting system power losses, but it does not affect the reliability of the oem system. A similar approach can be applied to the lowbeam circuit relay also to reduce power losses.

Higher wattage bulbs can degrade the reflector and the increase in lighting system power losses due to the higher wattage bulbs may also result in less light output than expected. If higher light output is the desire, why not try +100 or +150 55/60W bulbs that are now available. If light output claims are true, more light for the same power and no increase in reflector heating.