CB400SF Version R headlight bulb - help !!!!!!!

[BristolBoy]

I'm having problems finding a replacement headlight bulb for my 1997 CB400 Super Four Version R, and Fowlups here in Bristol can't even seem to find the bike model, let alone a bulb for it. I think the problem is due to it being the Version R with the rectangular headlight. The failed bulb is a 80/70 watt twin-filament which looks like a regular H4 bulb - except H4's don't come in 80/70 watt and the 3 mounting lugs (which hold the bulb into the bulb holder) are in slightly different positions. As I ride the bike daily, this is keeping me off the road (dark nights on the way home) - who'd have thought a simple thing like a bulb could cause so much hassle?

I've emailed David Silver and Wemoto, and am waiting for their replies. But if anyone knows what type of bulb I need (and a source) I'd be really grateful.

If all else fails, I'm gonna buy a standard 60/55 watt H4 and try to cut off 2 of the 3 mounting lugs (and pray the spring clip keeps it in place ).

[Cammo]

Yes you can just cut off 2 tabs from an H4, that's what I do on my nc30.

[amorti]

I'm having problems finding a replacement headlight bulb for my 1997 CB400 Super Four Version R, and Fowlups here in Bristol can't even seem to find the bike model, let alone a bulb for it. I think the problem is due to it being the Version R with the rectangular headlight. The failed bulb is a 80/70 watt twin-filament which looks like a regular H4 bulb - except H4's don't come in 80/70 watt and the 3 mounting lugs (which hold the bulb into the bulb holder) are in slightly different positions. As I ride the bike daily, this is keeping me off the road (dark nights on the way home) - who'd have thought a simple thing like a bulb could cause so much hassle?

I've emailed David Silver and Wemoto, and am waiting for their replies. But if anyone knows what type of bulb I need (and a source) I'd be really grateful.

If all else fails, I'm gonna buy a standard 60/55 watt H4 and try to cut off 2 of the 3 mounting lugs (and pray the spring clip keeps it in place ).

80/70 is a duff fitment. If you flash the headlight that's 150w, which at 12v is 12.5A, and your headlight fuse (unless the version R is different) is only 10A. So that means if you flash your headlight with engine running and making about 14.5v, then you are barely over the 10A, but if you flash it when idling, you'll pop the fuse.

Even if you don't pop the fuse, eventually you will melt the switch gear or some part of the headlight loom, often the H4 connector block.

Get one of these 90% brighter bulbs, it'll give you as much light as a cheapo 80w bulb.

[BristolBoy]

I tried fitting a Phillips Extreme Power (80% brighter) H4 65/55 watt car bulb (with lugs cut off). It worked fine on main and dip beam whilst stationary with engine running (and revved). Went for a run, got home, dipped beam filament had blown.

I fitted the other one of the pair of Phillips bulbs - exactly the same happened.

Digital meter on the battery showed correct voltages (13 and a bit with ignition off, 12 and a bit with ignition and lights on, 14 and a bit with engine running). As the original fitment was a 80/70 watt, I wonder if the bike is putting a slightly higher than average current through the bulb - which a 80/70 can take, but a 65/55 can't deal with? But surely they run off the battery, so current would be the same?

I'm going to fit a bog standard H4 65/55 at the weekend and try again - they may be a bit more robust than the high output Phillips bulbs. If that fails I'm fooked, because a genuine 80/70 from David Silver will take 6 weeks to arrive - and costs £55 plus postage

[amorti]

I tried fitting a Phillips Extreme Power (80% brighter) H4 65/55 watt car bulb (with lugs cut off). It worked fine on main and dip beam whilst stationary with engine running (and revved). Went for a run, got home, dipped beam filament had blown.

I fitted the other one of the pair of Phillips bulbs - exactly the same happened.

Digital meter on the battery showed correct voltages (13 and a bit with ignition off, 12 and a bit with ignition and lights on, 14 and a bit with engine running). As the original fitment was a 80/70 watt, I wonder if the bike is putting a slightly higher than average current through the bulb - which a 80/70 can take, but a 65/55 can't deal with? But surely they run off the battery, so current would be the same?

I'm going to fit a bog standard H4 65/55 at the weekend and try again - they may be a bit more robust than the high output Phillips bulbs. If that fails I'm fooked, because a genuine 80/70 from David Silver will take 6 weeks to arrive - and costs £55 plus postage

Sorry mate but that's nonsense - COMPLETELY impossible. 12v is 12v, current is drawn from the component not pushed from the bike, unless there is a fault. What has much more likely happened is that the higher wattage bulb has melted some part of the system and you are getting a short when you hit a bump.

[BristolBoy]

As far as I know, the 80/70 watt bulb is the original (it certainly came with the bike 8 years ago when I bought the bike), so if it was going to fry any wiring surely it would have done it by now?

Anyway, I put a bog standard 60/55 watt H4 in at the weekend and took the bike for a couple of long-ish runs. No problems - main and dip both work, and neither filament blew. So, I'm not sure what that proves. Perhaps the failure of the 2 Phillips high-power bulbs was just a coincidence (a faulty batch of bulbs, maybe). If the bog standard bulb is still working after another couple of weeks running, I might risk buying another high-power bulb and see if that survives.

God, I hate electrics !!!!!!