Lucas 700 headlight halogen conversion

Fitted to my Dommie way back. (ie when I still rode it).
Did the job, much brighter than the old sealed beam unit. 
Only issue I had was that for some reason, the lens would creep round. Nothing to do with vibration I'm sure! 
Still available on the Internet, in pairs. 

Why should changing the lens fitment blow the fuse? Not a relevant question.

I agree with Michael above and fitted a Wipac Quadoptics lens to my Dommie many years ago with a Philips Racing Vision H4 bulb.

The beam pattern is superb on dip and on full beam and would highly recommend this setup for anyone who does any night riding.  It totally transformed my rides home after many VMCC evening ride outs I took part in.

I have one in my spares box ,but did not think it would fit. I may now give it a try ! . The LED pilot and rear lamp bulb from Geoffy  absolutely transformed the visibility of the bike ,and i would urge anyone still using the sad  old bulbs to take the plunge . It may save your life.

The extra amps drawn by halogen won't be enough to hazard a fuse.  Old 45(?) Watts = 4 amps.  New 55(?) =4.5 amps.  Fuse is whatever someone fitted...possibly 15amps or more.

If you have a 55W headlamp there will be times when you have both beams on so we now have  almost 10Amps, then there is the 2 A for ignition. you always want a bit of headroom so you don't blow just because you operated (the stop light) so 20 or even 25 I would recommend.

SJ Motorcycle Engineering sell a single Wipac Quadoptic with pilot for £34.99, which is a pretty good price these days. Definitely a lamp unit worth having.

Geoffy is meant to be Paul Goff,  i think - the guy who sells classic electrical accessories OKA Goffy!

http://www.norbsa02.freeuk.com/