NSU Quickly S23 Restoration and Repair.: Nacelle and headlight removal and renovation, wiring

This bike has the usual, poorly preserved nacelle used on the S23/F23 bikes. Its not clear what this is made of but its some form of polymer that seems to degrade giving a loose velvety appearance. It also doesn't keep its colour well.

This view shows the sort of wear and damage to these old nacelles, the plastic surface suffers from uv degradation. Typically it becomes soft and develops abraded wear holes.

worn top surface to nacelle

Dirty/opaque glass.

damaged and discoloured sides

I wanted to try and restore the nacelle and since the headlight rim is rusty and the glass discoloured and dirty, I want to sort out the headlight as well.

The nacelle is held on by 3 screws- this one at the front below the key escutcheon.

Front mounting screw below escutcheon- this one likely to be very rusty

... and one each side at the top.

Side mounting screw

Headlight renovation

I found it impossible to remove the central nacelle screw because it was rusted in- this screw probably gets the worst of the weather and should be fitted with some corrosion block grease- sadly not in my case! I'll have to drill that screw out later, but for the time being I decided to remove the headlight and work on that. The headlight is held on by a screw above and below the light (see pic above). The small screw at the bottom of the lens is the beam adjusting light. I removed both the larger screws and the light pulled out to be held by its wiring connectors- more complex than expected for such a simple bike. I took several photographs to identify the wiring connections.

Note these connections from left to right: Green single; 2 cream double; red cream double and single red

There are two red wire connections- one is connected as a double wire whilst the other is connected singly. I marked the single wire with a blue pen.

... and twisted both double connections together for identification. Note the brown wire from the loom to the side rivet

... and a second from the block to the other side rivet

The beam adjuster screw (smaller screw to the rear in this photograph) was badly rusted and its spring fell apart when I removed it. The larger screw is a mounting screw which I had reinserted for safe keeping.

Front view of these two screws.

The glass pushes backwards and revealed the silvered surface was badly corroded and the glass needs cleaning.

I removed all screws from the headlamp surround

The surround was corroded and pitted

I set this aside for rust treatment and cleaning.

The rear part of the light had separated from the the frame as a corroded silvered reflector/bulb holder and a metal mounting frame. The reflector was held in the frame by a bifurcated rivet each side (4mm diameter and 6mm shaft length). these were also used as connection points for brown (Earth?) wires as below.

Squeeze the rivet ends and remove them to release the reflector.

Bifurcated rivet removed. I ordered some new ones but it might have been easier to replace them with BA nuts and screws.

second rivet removed- carries brown wire connection.

Removing the rivets separated the frame whichwas in fair condition but the sealing strip will need replacing. Note rubber washers on reflector mounting points.

The reflector was rusty on both sides, the adjusting spring is visible here but it was so badly rusted it fell apart when removed.

Beam adjuster spring

broken!

There are two springs on this reflector- one was clearly part of the beam adjuster mechanism above, but the second (picture below) seems to do nothing as it connects two fixed parts. I will replace this but its function is mysterious.

I treated both the reflector unit and chrome surround to wire wheel brushing, sanding with wet and dry 180 grit, followed by Jenolite. I could then spray both parts inside and out with etch primer. I also sprayed the surround with high build primer to cover the chrome pitting and then sprayed both with Halfords own brand silver engine paint. This cures at room temperature but is also heat stable and so should survive the sort of temperatures reached in the headlamp unit itself. This isn't as good as a proper chrome reflector but it must be better than the rusty surface I had found in the light.

Chrome surround resprayed and ready for reassembly.

Reflector re sprayed silver and smoothed out

Nacelle

I was eventually forced to drill out the lower nacelle screw, and although this successfully released the nacelle, it did mean that I was faced with disconnecting the speedo cable and wiring. The speedo was straightforward, it simply unscrewed. The speedo itself is held by a wire spring clip and just unclipped.

Sadly the wiring was more problematic- it was pretty chaotic and I think non-standard with several replacement wires providing new power and earthing points installed over the years. I took a number of pictures to try and sort it out but frankly, as I think its been over-modded over the years, I think addressing it from first principles will be a better approach- perhaps installing some modern multi-plug connectors. The situation was worsened since the lighting switch disintegrated when I tried to unscrew the wire terminal screws! The whole thing had become very brittle. As a result I was left with a lot of loose wires a requirement for a new switch and a conundrum!

The Nacelle was pretty nasty and appeared to have absorbed some of the oil used to try and free the rusted screw. The unit still had the old ligth switch knob, key escutheon and NSU shield attached.

Removing the badge was simply a matter of straightening the clips and pulling it thoroughh. The key escutheon was held on by a 3mm diameter rivet which had to be drilled out.

Badge removed Note oriinal glossy finish beneath.

Key escutcheon, swing plate and washer plus rivet- which will need replacing.

Removing the headlight knob was awkward- it looked like it should just pull off but attempts to do so were clearly trying to pull the iuside through the plastic.

Remnants of the headlight swiutch- the contact plate had cracked off leaving only the swinging contacts inside, and operating knob on the outside

In the end I removed the split pin and separated the spring washer and swinging contact from the switch stem. The switch part then just pulled out. I don't know how you would remove the switch if it was intact but I'm assuming that the contacts plate would also separate once the split pin was withdrawn.

Remaining components of the switch- no base plate!

Once the switch was off the scuffing damage to the top of the nacelle caused by its operation was obvious. The deteriorating plastic had become very soft and crumbly and was now deeply scratched/scuffed in several places.

... and when cleaned up the original finish was clear too. Sadly this doesn't last as the plastic weathers poorly.

It seemed to me that the crumbly and friable surface of the nacelle needed stabilisation before it can be resurfaced. However, despite washing and de-greasing as much as possible, the surface of the plastic was still hydrophobic and so my original intention of stabilising with water-based PVA adhesive wasn't likely to work. The alternative of covering in glass resin was also likely to adhere poorly. I decided that the best approach was to use a spray paint formulated for plastic to prime the surface and follow this with some filling using primer-surfacer. This was a bad idea- the spray filler primer was incompatible with the plastic paint and I was forced to strip it all off, rubbing down as best I could and then re-prime with acrylic grey primer.

I could then skim with P1000 fine surface filler to fill the numerous scuffs and let this set before rubbing down again.

Addendum: Plastic repair

So far I had been really pleased with the renovation of the nacelle. Unfortunately whilst finally fitting it to the handlebars I dropped the thing, and as a result the rear top edge (the part that conforms to the handlebars) cracked away. I couldn't even find one of the pieces! I was faced therefore with either replacing the entire nacelle (originals unavailable but GRP reproductions can be had at a cost of some £140) or finding some way of repairing the damage. I could stick some of the broken pieces back in position using Gorilla Glue, however once attached they had no rigidity at all. I therefore sought some sort of reinforcing material. I came across a form of heat moldable plastic card (FormCard). I ordered some via eBay and it arrived as 3 credit card sized pieces of heat moldable plastic.

Form card via eBay, the black sheet has been removed and cut in half with scissors.

These are easily trimmed with a pair of scissors or a knife and I cut one in half lengthwise. I was then able to heat this using the hot air gun and mold it into position underneath the nacelle and overlapping the rear edge below the reattached pieces. The plastic adopted the shape of the nacelle well and also stuck quite firmly to the nacelle plastic. When cold I had a hard repair.

First attempt, the plastic has stuck but its not quite up agaiunst the nacelle material. I need more plastic on the left to fille out that space and ideally I need to reduce the thickness to prevent the nacelle from standing too proud over the bars.

The only problem was that it did not conform well to the dimensions of the handlebars and it was also quite thick. Material in this position will obviously push the nacelle upwards so I needed the repair to be as thin as it could be and still give support. Luckily one of the advantages of this card is that it can be re-molded several times. I therefore wrapped the handlebars in cling film to prevent sticking, and reheated the plastic. I could then push the nacelle into position over the bars and so press the plastic tightly up against the nacelle material.

Bars covered in plastic, pressing the nacelle down

This meant that the plastic would now fit over the handlebars snugly, but it also pushed the plastic upwards to fill the gaps left by the missing pieces of nacelle.

After pressing- plastic has bulged upwards to fill the missing sections.

I had intended to use the white plastic card for this repair and started with the black only as a dry run. However, its been so successful I'm unwilling to remove it and repeat with the white! Thus, although it is going to be difficult to paint, I'm going to persevere with trimming, filling and repainting this repair.

So after many setbacks... Don't ever try to apply hi build primer filler over new paint (the acetone content will strip underlying paint) I eventually arrived more or less where I had been a week ago!

I refitted the badge and lock escutcheon

I could then test fit the repaired nacelle before trying to assemble the electrical connections. To my surprise it did fit rather well and the extra thickness of plastic around the handlebars wasn't really noticeable.

Electrical

The old light switch was defunct and the wiring looked tired. I decided to fit a new switch with new wires (8 amp) for better conductivity. As I am fed up with short wires I decided to make the loom longer and fit some quick release multi plugs as its ridiculous to have to disconnect everything in order to remove the headlight say to change the bulb. I hope it will all fit!

4 pin spade type multi connectors Crimp the spades to to the wires and insert from the back of the multi plug until it clicks into place.

Assembled connector

I ran short fly leads from the headlight to the connectors using the original colour codes with the exception that I used brown instead if grey. I will insert the wires into PVC sheathing but this will need to be a little wider than the original as my wires are thicker. I ordered 1m of 0.8mm id sleeving to run to the dip switch and 2m of 0.4mm id sheath to run to the magneto and on to the rear light. I'm running a black lead to earth through the multi plug too.

Headlight as connected to the multiplugs. The leads from the plugs on have been sized to give a generous allowance for their destinations.

If bought a Euro spec light switch by accident. This isn't suitable for twin filament bulbs and wasn't a direct fit in the nacelle either. It required modification.

EU light switch; the most obvious difference is the long copper contact not present in the UK version. Note the small wings also on the side of the base plate. These obstruct fit in the nacelle.

Light components disassembled,

I eased up the rivets to remove the copper contact. You have to be careful but it can be done with a tin blade. If you do break a contact then it can be replaced with a 2mm eyelet. Once the copper is removed the switch behaves as a simple on-off and can be wired through to the dip switch on the handlebars.

Copper blade contact removed, wings yet to be filed.

All that I needed to do then was to file the edge wings flat and test fit in the nacelle.

Insert the knob...

add the paper from the inside

followed by the switch and spring. Spring base-plate now fits into nacelle recess. Compress the spring and fit the square profiled washer, retain it with a split pin. The two red wires here were a temporary fix so I could check switch function in position.

Wiring up the switches presented a small problem as I'm not sure how much wire is too much, but in the end I got it all connected. I present the wiring diagram I used as below. As my wires were thicker that the originals I had to make splice joints where two wires needed to enter a common terminal. The only other change was to use brown wire instead of grey and to run a separate black lead to earth the headlamp via the multi-plug.

Not looking too shabby now it's refitted

Wiring the dip switch/horn

I removed them switch as it needed to be fitted to the new bars. Its held by a single clamping screw underneath. The clamp consists if three removable metal straps joined by a screw. All were rusty and as this forms the earth return for the switch, all needed cleaning.