i can only find one image of this headlight on this site in optical part,did it have a domed lense,lucas cat eye?,if anyone knows,thanks.

email (option): any-old-iron@hotmail.co.uk

The MU42 (domed glass) headlight replaced the DU42 (flat glass) headlight. The shell, rim, rim fastener, glass seating and reflector seating all differ from the DU42...I'm not sure if the MU42 saw wartime use..if it did it would have been right at the end.Certainly thier introduction was around that time. They were routinely used postwar as a replacement for the earlier type.
The late switch panels with the switch you describe aren't common but do turn up now and again.
If the question of when the MU42 lamp was introduced can be resolved and you need one, I have enough parts to assemble a perfect one, which is complete apart from the switchplate and switch but has the 'hard to find' rubber seal....Ian

email (option): ian@wright52.plus.com

I just checked out my Lucas equipment info. and the MU42 is listed as introduced in 1945..So the only question is when in 45 it was introduced and whether any made it onto WD bikes before the end of the war.... .The current website page picture shows Vokes filter equipped M20s, so they are from one of the last two wartime contracts. They have blackout masks fitted but the rim clip of the DU42 type headlamp can clearly be seen, so I guess maybe not...Ian.

email (option): ian@wright52.plus.com

hi ian,thanks for reply.
you helped me out with info.the mu42 was introduced in 45,as was the bakelite push button.as shown in the bsa wd m20 electrical equipment/in the light switch category on this website,the reason i ask if they have the domed cat eye lense,is on the image you cannot see,but i own one of these lights,and it has the domed lense.its covered in rust and appears all original,did these lights go on nortons also with this war time modification?,thanks chez

email (option): any-old-iron@hotmail.co.uk

I don't know about the Norton..I should think someone who knows them better than me will answer that.
Do I understand you correctly that you have an MU42 with the late 'push' type switch?....Ian

email (option): ian@wright52.plus.com

hi ian,yes i do,i could send pictures,just trying to identify the light best i can,as there is little info/images to go on,thanks chez

email (option): any-old-iron@hotmail.co.uk

I've never seen that combination of parts..It may have been a postwar replacement part..or some mixed parts put together in the past....Ian

email (option): ian@wright52.plus.com

hi ian,its a bit of an unusual barn find,it does appear all original,all rusty,but could be an early combination,thanks for your help ian...chez

email (option): any-old-iron@hotmail.co.uk

Hey Chez,
Just to add my bit, there are two types of the late panel, type one had the push switch in the normal switch position, as fitted ot M20,16H etc and type two had the push switch in the ammeter position for use on the G3L. This was because of the closely positioned speedo.
Cheers, Mick.

email (option): mick@motorbikemike.org.uk

The information on the use of the modified electrical system is scarce.
The late issue of the M&I manual does refer to both the usual as well as the modified system when describing the headlamp and switches.
It does however only give an electrical wiring scheme of the old system.

Spare parts lists on S5161, the only contract on which it is likely to have been used, does not give the modified system. Not unusual as the Norton spare parts lists are not very informative on the electrical system at all.

There is at least one bike in Australia having this system mounted which has apparently been restored using the parts on it.

I tend to think that the domed glass was introduced after the hostilities.
Before that, bikes were delivered with black out masks and not with glasses.

Cheers,

Rob

email (option): wd16h@telfort.nl

As a slight off-shoot of this, would very late (as in last day of production) blackout masks been the hooded type mask or might they just as easily have been a plain flat plate with a hole cutout set in to the standard rim? From the serial number my machine calculates out as being, most likely, of that date. It came to me with a domed glass but there is no guarantee that it is the original unit. As an aside, my thought is that it must be illegal, as well as a bit dim, to use a bike on the road with a blackout mask fitted? Thoughts?

email (option): cruiserchooser@hotmail.co.uk

No not illegal! Since up till now you could have a bike MOT'd for daylight use only (ie no lights. such as a trials bike). The normal practice would have been to tape over any running lights and get a daylight MOT. But of course now not even an MOT required for a pre 1960 vehicle. Ron

email (option): ronpier@talk21.com

I apologise for the thread drift here.

I understand the point about a 'no lights' bike. But if it has lights fitted then I always thought that under 'Construction and Use' (or whatever it is officially termed these days) all lights had to comply to current, relevant lighting spec and that they all had to work. You are not allowed to be selective and say 'I am keeping this part of the setup working - but not that part'. In the same way that if a bike has any part of an indicator system fitted then they have to work - irrespective of how proficient you are at hand signals. I'm not sure that the vagaries of the (now non) MOT actually have much bearing on the points of law of Cons & Use. But I am always glad to hear of water tight cases for the opposite! I also appreciate that it is probably quite unlikely that one of our esteemed officers of the law are likely to make an issue of a vintage machine and that this is likely to be an 'academic' discussion - until it is in an accident. Even then it is probably more likely that an insurance company will use it as a 'get out' should there be an accident and it could be alleged that the rider was to blame due to the inadequate/blanked out light. But here I am getting even further from the light.

email (option): cruiserchooser@hotmail.co.uk

I'd suspect that this is an area that is not legislated for. Rear lamps such as the MT110 would not meet any current legislation but remain legal for vehicles of a certain age. I've seen the regulations which required the use of black-out masks during wartime (also for civilians)and the reduction of the requirement but never anything to say that black out lighting must not be used. Best bet would be to ask the Police Officer if the war is over. When he replies "Yes", ask who won and when he says "We did", say "That 'll 've upset the Kaiser then !"

Only a B.F. would ride with a headlamp mask in visibility which required lighting, but in daylight I can't see why they'd be any more illegal than pop-up headlights on a car (and Triumph TR7s often had one up / one down !) There is no requirement to leave a headlamp uncovered at times when its use is not required.

If the UK were to introduce daytime headlamp regs then there would be a problem but there may then be a historical exemption, as in France where it does not apply to pre-1965 motorcycles.

hi,just a reply to mick holmes,the light has the push button fitted in the light switch position,like on the m20,thanks chez

email (option): any-old-iron@hotmail.co.uk

Here's the 1945 type blackout mask, looks a bit like the car/truck Butler one, but this one is Lucas:







You can see the big advantage over the earlier model!!

Cheers,

Lex

email (option): welbike@welbike.net

I had my reflector resilvered when I rebuilt the bike but had the mid war blackout fitted...Riding around Devon lanes at night that I am very familiar with was frankly a scary experience, requiring absolute concentration and slow speeds...and I was panicking all the time about badgers, foxes, wild boar and rabbits...none of which I would have been aware of until I hit them probably....It's no wonder there were so many accidents at the time...Ian

email (option): ian@wright52.plus.com