Ebay dealer

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Mar 6, 2007
I wanted to convert my Mk 111 to run a quartz halogen type bulb and after fiddling/modifying the bulb holder, managed to get it to hold an old QH type bulb correctly. I'd fitted the Sparx high output alternator so next thing was to slot in a much more powerfull bulb.
I tried Halfords but they wanted around 20 quid for the 100/80w xenon bulbs. So I tried Ebay and found this guy


7.99 for a pair and free delivery, bargain!!!

I paid me money and next day they turned up. I had to "modify" the bulb by chopping off most of the big circular fitting flange so it would fit into the headlamp shell, but a few minutes with a Dremmel cut off disc did it nicely. In it went and only then did I realise that the bulbs were not in fact the 100/80w I had paid for but only 60/55w. Bugga.
I send the seller a message late yesterday afternoon and this morning a new pair of 100/90w xenon bulbs show up. No request for extra payment, nor am I asked to return the incorrect ones. Not that I can, after setting about them wi the Dremmel anyway.
Now I've done around 300 deals on Ebay and to be fair I've had very few complaints, but this is exceptional service and well worth a plug.

Hi Millard
I hope you fitted a relay to power that headlight bulb; if not your switches and associated wiring will soon be nicely toasted!!
On a separate subject is your starter working ok now?
mikeymike552001 said:
Hi Millard
I hope you fitted a relay to power that headlight bulb; if not your switches and associated wiring will soon be nicely toasted!!
On a separate subject is your starter working ok now?

hhmmmmmm!!!!! back to the drawin board then eh? :(
never thought of switches fryin, is that a real possibilty? :?

The starter is back to normal cheers, me right knee is ever so grateful :D
Hi Millard
yes it most certainly is; you're asking the switch and wiring to handle almost double the amps it was designed for!
I had a word with my father(a retired electronics engineer) about a suitable relay and to make a wiring diagram up for you, we found a suitable relay but he pointed out that the high wattage bulb would also generate almost double the heat as well; and that in the confines of the headlight shell it might well get hot enough to melt the insulation of any wiring that comes into contact with the outside of the reflector.
even more toasted wiring!!
Mike, thanks for flagging this up for me.
I'm gonna put a fuse link on the headlamp wiring and keep a close eye on things for a while to see what happens.


I do suggest that you fit relays with heavier gauge wiring, as any fuse you fit would probably need to be at least 10A continuous rating, this I think would actually exceed the amp rating of the wire?
OK guys, thanks, I'm gonna take yer advice.
Do I need to fit heavier wiring just inside the shell due to the heat? or are you suggesting the whole electrical path via the switches. Also, as I don't actully switch them on and off very often ( I tend to leave them on) do I need to fit the relay?

The more its on the more you need the relay, have you considered a cooling fan in the base of the headlamp shell :D . Hope you realise these bulbs are for off road use only :shock:
millard said:
Do I need to fit heavier wiring just inside the shell due to the heat? or are you suggesting the whole electrical path via the switches.

If you don't then the "heat" could be generated by the wires themselves!

The original battery (brown/blue) wire is in my own opinion, only just about adequate for the standard electrical system, so the ideal solution would be to run a (fused) 28/0.30 wire directly from the battery to relay 1 (lights off-on control).

Relay 1 would then be wired so that it was energised by the handlebar lighting control switch (as it is a Mk III), or even directly from the ignition switch, and the standard switch wires are perfectly adequate for that.

Then you have (at least?) two options, either individual relays can be used for each beam circuit (powered by relay 1), each relay would be switched by one of the high/low standard gauge switch wires, or a single 5 pin change-over relay could be used (also powered by relay 1) as that would only need one standard gauge wire from the (preferably) high beam side of the dip switch as: power off = dip beam (relay terminal 87a connection), power on = main beam (rel. T 87 con.).
The good thing about using a change over relay (apart from it being simpler) is that if the power from the main beam switch to the relay should fail at night for some reason then the relay defaults to dip beam immediately.
If the switch power fails with the two relay option then the beam goes out until you flick the dip switch over, and if the failure is in the switch feed wire then that will still leave you in the dark just as if no relays were fitted!

Don't forget to upgrade the headlamp earth wire as well. (All power wires between battery and both bulb connections and earths I think need to be at least 28/0.30 = 17.5 A standard gauge cable, or thinwall 28/0.30 = 25 A) As the electric starter is used then do not fit any additional earth wires to the battery, only connect the heavy starter earth wire to the Pos. battery teminal, do not connect any other earth wires.

Others here could have different opinions about how best to do this?
If so then let's hear them please?
Hi Millard
I have to agree with everything L.A.B. says, I’ve purchased a suitable double pole relay from Maplins this afternoon and during the course of the week I’ll make a test rig up in the garage to make sure the circuit I have in mind works ok.
Bear in mind though that to use this illegal high wattage bulb will involve some quite considerable alterations to the wiring including running a much heavier power supply lead direct from the battery to the relay and as L.A.B. says the relay must be wired “fail safe” so if the field coil supply to the relay fails the headlight will automatically drop onto dip beam and because of this a single pole relay really won’t do the job safely in my humble opinion.
I know it’s hard to understand but if you double the wattage you almost double the heat produced, if you go into Homebase or B&Q and look at the lamp shades you’ll see that most have maximum recommended bulb wattage, and if you exceed that you run the risk of scorching or setting fire to the lamp shade.
My own bike is fitted with the standard H4 quartz halogen bulb which I find more than adequate for night time use, if your bike was originally fitted with a tungsten bulb headlight It might pay you to consider the quad optic headlight unit that Norvil sells; (part no 050100rh) as far as I know it’s a straight swap for your existing light unit and at just over thirty three quid it would be a lot less hassle than having to hack your wiring about.
I fitted some quad optics to a car I restored many years ago and they gave really excellent results.
I hope this help you a bit
Regards Mike
think it would be MUCH easier to just use a 60/55w Xenon.
I can't be arsed friggin about wi the wiring that much for the occasional night time ride.
I did the conversion so I could use QH type bulbs and then saw the 100/80 Xenons on ebay and thought they'd be a good idea without realising the consequences.
The QH conversion still holds good so I'll swap to a lower wattage bulb instead.
Very much appreciate your advice guys.
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