NSU Quickly: Bing Carburettor Strip Type 1 12 136

This carb strip was carried out because the thing was hopelessly gummed up. As I haven't yet re-assembled the bike,I have yet to run it in any way other than a test firing. Consequently I don't know if this has effected a repair. This approach should be fine for a carb that is simply dirty or blocked- provided that there was no underlying problem. I should also add that tuning carburettors (especially in the light of today's modern fuel and oils) is something of a black art! I'd love to understand it but I don't. Look out for a future post detailing my attempts. However, I should add that Shane Woods (contact via fb group) can offer a carb rebuild and tune service and he has helpfully also penned a few comments relating to this account which I have reproduced after the blog.

The carburettor  is located on the rhs. In this bike the choke button was jammed down and the throttle cable stuck firmly. It's held to the manifold by 2 nuts each fitted with 2 washers and easily removed. However, as I couldn't move the throttle slide I had to remove the carb with the cable attached. Detaching this from the throttle control showed that the cable was frayed internally and jammed in the throttle control. 

Motor from rhs- jammed carburettor

The carb top is held by 2 M4 cheese head screws. Once these are removed the top should be removable, but in my case the throttle slide was jammed internally would not come out. This carb was clearly doing nothing as it was jammed at both ends of the cable! 

Carb top removed but stuck via the throttle slide. Note the fractured gasket that should be fitted below the cap.

The choke slide however could detach from the operating plunger and could be removed.

Choke slide removed

I removed the lower needle jet cover

Which revealed a lot of debris in both the cap and the jet beneath it.

The jet unscrews from the carb body, both cap and jet were dirty.

Once the needle jet was out I could free the throttle slide by using a drift to tap it up from the bottom.

The main jet is accessible from the side as a small brass nut. 

This unscrews to allow the jet to be removed.

The float chamber lid is retained by 2 M4 cheesehead screws

There was some dirt in the cap...

Float cap once removed. Note sealing ring around periphery of the cap.

... and more dirt on the body of the float.

The float did however simply lift out

The throttle slide could only be removed by tapping with a wooden drift from below. There was evidence of white corrosion on the slide which had probably been responsible for obstructing the slide.

Throttle slide removed, view 1

Throttle slide removed, view 2

Base of throttle slide was pitted but hopefully this will have no effect on function.

By compressing the spring the cable could be slipped into the removal hole and unclipped allowing the spring to be removed. Beneath the spring there was a ring washer and beneath this the needle  with its positioning clip. In my case the needle was obviously pitted and will certainly benefit from renewal.

I placed all the components in the sonicating bath to clean and then brushed them clean. I sprayed all parts with carb cleaner ensuring that all jets and passages were free and then loosely reassembled the carb until I can get some new parts.

Carb type 1/12/136

New carb top gaskets are paper, and have been so for some time. The fragmentary remains I removed from the carb when I stripped it were rubber and this suggests it was probably the original. I'd like to have found a rubber one to replace it with, but just couldn't. In the end I cut a new gasket for the carb top from a sheet of nitrile rubber. I'm now informed that these gaskets never were rubber and although I've not had a problem with my home made inseret there are pitfalls (see comments at end of blog). When I stripped the carb I found the float bowl gasket to be a square section 23 26  O ring. I used a round section 1.5 mm thick O ring which worked well. Too thick an O ring here could raise the  float height so again caveats in  comments at end of the blog. The needle jet cover plug had a fibre washer and the  main jet an O ring. Both were easily sourced.

So I've refitted the carb and tried to start the motor- this immediately revealed that I had no spark (see "Magneto"). However having sorted that, the motor did start but as I have no throttle cable at present its hard to be certain how well it runs! More later....

The Acquisition

So this is the newest acquisition. Strangely its the fourth Quickly I've owned but I'm expecting it to be the first one I've really got to grips with mechanically. I found it for £275 at Kempton park bike jumble. Clearly it has problems, all cables are snapped snagged or missing, the gearbox seems to engage at random and although the motor turns it wont start- the carburettor appearing to be jammed. Add to this the missing rubber parts plus two flat and horribly worn tyres, and there is clearly a lot of stuff to get to grip with! For the moment here is the bike: When I got it it had no reg number (which I'm hoping isn't ominous) but most of the bike is there even if in poor condition. The rear light fitting still bears the original supplier's decal so I'm think stabilise and conserve rather than restore.

No reg number, but original decal on rear light fitting

Closer examination shows bike supplied by Granby Cycles of Blackfen. Owned at the the time by Ron H Argent.

The bike was obviously a 2 speed model, and a single seater. This suggests its a S23 model made between 61 and 65 and fairly common. From the NSU quickly spares site, model identification page the details of this model are chrome wheel rims, streamlined cowling with integrated speedo and oval headlamp. The toolbox has moved from the front to the space behind the saddle tube. In fact there were  still a few tools in there! This model also has the larger fuel tank holding 1.5 gallons and the tubular centre stand instead of the earlier wire type stand; a definite improvement. I was expecting a 3 speed transmission by this time, but apparently that was only used on the S2 23. Some 28435 S23 bikes were made so this one isn't particularly uncommon. 

2 speed gear change- not shown here though, there is damage to the grip end.

• 
  

Here are some overviews below- I'll add some more when I get it off the trailer.

LHS view

RHS side... Yes the front tyre is flat

Motor from rhs

Motor from lhs- jammed carburettor

Front wheel- tax disc holder also lacks identifying disc.

Obviously used to have a front Number plate- slightly worried as to why tall identification has been removed from this bike!! Front mudguard badge present but faded and maybe dented.

Rear wheel

The bike had the more modern streamlined nacelle containing the later speedo. Mileage 6345 relatively low if genuine. The nacelle has undergone its usual tatty degeneration. It gets this furry, almost velvety finish which only gets worse on sanding. It tends to be brittle too. It clearly needs some attention but as these are really rare I will try to renovate first. The light switch is original and the headlamp rim needs attention. I doubt the chrome will be salvageable. I'll probably paint this along with the bars.

Nacelle present and has original light switch- bonus! ... but does it work?

The frame plaque shows that this is a 23 inch wheel model; a Quickly 23, (known as an S23) with frame number 1022365 and built in 1963.

Frame plaque on steering head, cable damaged.

The motor has number  16596956.  Its hard to say if this is the original motor because exact frame-to-motor number correspondence isn't known but this number certainly corresponds to  motors manufactured in 1963. The air intake hose connecting to the in-frame filter is missing although the filter appears to be  present...

Motor number on lhs below (missing) air intake rubber elbow.

... as is the rubber cap sealing the other side of the filter element.

Air filter cap present

The fuel tank is of the larger size. Paint clearly worn through in places. One badge faded but present, the other is missing. Fuel tap is present and not siezed. Inside tank appears clean with no rust around the inside of filler cap.


Frame trim piece present, slight chips but not broken.

Toolbox lid surprisingly also there. The box contains a variety of tools, nearly all non NSU, but there are 2 (!) NSU original plug spanners. The remainder of the tools aren't even metric which makes me wonder how well this bike has been maintained!

Tool box opened- lid and fastener still present- contents mixed and mainly non-original.

There was some fibre packing inserted in the rear mudguard just above the frame join trim - I suspect to stop it rattling, so I'm looking at a small weld repair to the mudguard seam here. Hopefully it will be just a spot weld.

Packing in rear mudguard

Clearly a lot of work here, but I'm in no hurry and will take my time. I have other bikes to be getting on with so I'll try to acquire a few needed parts while I get around to starting the project. However, I can see the jammed carburettor as a self contained job and I will need to strip this to see what parts are needed so I'll start with that first.