Headlamp and Nacelle.

Working my way across the bars my next job was the nacelle. This is composed of 4 parts- a left and right side panel- top panel (inc speedometer and light switch) and a chromed front face (cowl) in which the headlamp is mounted. All panels are designed to click together and to be held by screws. The side panels are held onto the fork legs by 2 machine screws each (1 large cheese-head screw and a smaller cross-head screw), and attached to the top section with cross-head screws. The front cowl and headlamp are held on by 2 machine screws which screw into captive ferrules moulded into the plastic of each side panel and a small machine screw which fastens through the top. 

rhs of nacelle- note the two screws holding the side panel on, light switch and small top screw

Nacelle lhs- again note the 2 fixing screws.

In my case the nacelle was relatively intact but it suffered from several cracks, further as I disassembled it, it became clear that most of the locating "click lugs" were cracked or broken. Sadly none of the pictures I took during the dismantling came out, but pretty much all the screws were rusted in place. The crosshead screws did undo with WD40 but the two large cheese head screws (one on each side) were loosened only with an impact hammer. The small crosshead screw on top of the nacelle and holding the headlight on had to be drilled out because corrosion had  fixed it in place and obliterated the head. Having removed these the headlight cowl was still holding the nacelle together. This is held on by 2 slot head machine screws which screw into metal inserts moulded internally onto each side of the nacelle. In my case both of these screws had siezed and turning them simply rotated the captive ferrules ripping them out of the plastic- I suspect this had happened already because I didn't use much force. The headlight fixed in the rusty cowl and with one of the broken ferrule inserts is shown below.

Ferrules ripped out of the plastic side panels visible on the inside of the headlamp mask

I left these in penetrating oil overnight and the next day was able to remove them fairly simply by holding the insert with pliers and unscrewing from the front. The nacelle was then in a fairly sorry state but I was delighted that the cracks could all be reinforced using a hot-glue gun and I was also able to rebuild the insert sections to retain the ferrules as well although sadly neither hot glue nor Araldite proved strong enough to hold these ferrules in place as the headlight mask was screwed on. I was forced to find another way (see on). 

Having taken the headlight off the side panels remained attached to the top section and to each other (beneath the headlight mask) by click-lugs. I carefully separated these to remove the individual panels. The top section remained on the bike held by the wiring to the light switch and the speedometer cable.

Separating the front click-lugs that hold the two side panels together beneath the headlight mask.

The next step was to remove  the headlight reflector body which is still attached to the chromed mask or front cowl. The reflector is held by 2 slot head screws and the beam adjustment mechanism at the bottom - a long screw, spring and captive nut. The top retaining screw had already been drilled out (see above). The slot head screws presented no problems but the beam adjustment mechanism was hopelessly corroded and I was forced to cut through the adjustment screw with a Dremmel and disc. The adjustment mechanism contains a spring (also rusted through) and a square nut that fits into a moulding on the reflector so I carefully saved the nut. There is also a wire connection here which came away as the screw was removed- and a flat tab which seems to be required for electrical continuity- I will have to investigate the purpose of this strip but a similar piece is evident in the quickly (is this something to do with the rear light?). This wire connection and the cut beam adjustment screw is shown below. Once the screw was cut the headlight came out of the cowl easily and the glass separated. Luckily this is in good condition so was stored carefully for safe keeping. 

Wire connection to beam adjustment screw. I suspect this isn't original but was just used as a handy earth- given the level of corrosion that wasn't a good choice. Note square nut on the adjuster thread.

In order to remove the nacelle top section I had to unscrew the speedometer cable and remove the wiring connections to the lighting switch. This was suprisingly simple and had just 3 connections- two wires to left terminal one to the right. I disconnected the wires, taping the two for the LHS together to avoid confusion...

Wiring connection to light switch

... and as a safeguard(since the grey and green are now quite similar in colour) I added a Sharpie marking to the wire heading for the left hand terminal.

Surprisingly this switch was structurally very similar to that used in the NSU Quickly. It is however intended to be much more complex and multifunctional; straight forward is starting with lights off, to the right (clockwise) is lights on and turn to the left (anticlockwise and hold) is the kill function for stopping the motor. There were simply not enough wires to perform all these functions and I concluded that this is in fact a Quickly lighting switch and the kill function has been displaced to a button on the handlebars. I subsequently found that the original switches for the Quick 50 are obtainable but extremely expansive.

New switches are available €50 plus the rest!

 Even so the switch I have appears not to work- its is obviously dirty and notchy so I'm going to take it apart, clean and repair as much as possible. I'm following the NSU Quickly method; depress the washer to compress the spring and withdraw the split pin.

And lift off the washer...

Lift off the spring and 

then the moving contact arm.

The contact plate then lifts off the switch shaft. It was cracked and this had allowed it to bend a little so that the contact could not make clean connections in all positions thus explaining the lack of electrical function. I cleaned all the contacts on the plate and of course the arm and used silicone lube on the switch shaft.

Before reassembling the switch on top of the nacelle. I added a plastic spacer below the contact plate to support the area where the base plate was cracked and fixed it in place with the glue gun. Hopefully this will prevent the plate from bending as the switch is turned and allow the moving contact to connect with the terminals as originally intended. Using the multi-meter it seemed that 2-way switching function had been restored.

I de-rusted the headlight mask but it was severely pitted and I doubt even re chroming would be successful. I therefore simply painted it in silver Hammerite- the hammered appearance disguises the surface pitting. I could then refit the headlight reflector which required replacement of the beam adjustment mechanism but this was simple using a new screw and spring and incorporating the original square nut.

Reassembly of the nacelle however could unfortunately not be achieved by reversing the process of disassembly. I thought about how to replace the front mask screws which now had no ferrules to screw into. These screws take quite a lot of pressure and simply sticking the ferrules back in place hadn't proved adequate. I needed a stronger solution. I could have simply made a bracket and secured it to the side of the nacelle with screws; but this would have meant drilling holes and destroying the look of originality. In the end I made a rod harness which could be attached to the cheese-head screws at the fork legs. To do this I used a length of M4 studding with an eye bolt fastening at one end and an M4 threaded connector at the front. The eye bolt could slip over the securing screw and the connector provided a threaded opening for the mask screws to screw into. 

Two M4 studs prepared- eye bolts joiners and lockscrews

I originally intended to fit the ties inside the fork struts which meant I needed to replace the two cheese headed screws with longer versions so that there was enough protruding between the support legs to slip the eyes over. I used M6 flanged Allen screws as these fitted the recess in the nacelle side panel perfectly. I used an m6 nut on he inside of the thread to hold the eye bolts on the screw. I also replaced the M4 screws that hold the mask with new ones. Test fitting the rod straps is shown below. 

Test fitting the rod strap to the RHS inside the fork support leg- viewed from the left. Note the new (longer) screw passing through the fork strut and available to accept the eye bolt screwed onto the M4 studding. The front end of this studding has a threaded M4 connector into which the mask retaining screws can be fitted. There is some adjustment in length possible in position by screwing the eye bolt and connector along the M4 threaded rod and lock nuts to secure the ends when length is correct.

Sadly this proved impossibly fiddly to fit- the ties were out of place and would not align with the cowl securing screws. I had to move the ties to the outside of the support legs- where of course they will force the nacelle out sideways. To minimise this effect I welded the weyes in position and then reduced the thickness of both the eyebolts and the studding by grinding away both sides. This still causes some distortion in the nacelle fit but hopefully and acceptable amount. It also had the advantage in that now the ties were effectively clamped between the support leg and nacelle they could be held in position.

Using this setup I was able to refit the original cheese-head screws and mount the nacelle. I'm pleased that at least its back together and sound although I may have to work on some of the gaps-in particular the flex and clutch cable entry on the left prevents the top section from fitting properly onto the left hand side panel and I had a slight gap at the front where the click-locate flange is broken. Note these pictures were taken after Id decided to replace the light switch.