Siezed cylinder and piston; removing fuel tank covers and chain.

I didn't want to start restoring  this bike in a serious way, but I was hoping to free up the piston and maybe see if I can get it to run before deciding whether to restore it myself or sell it on. There is insufficient room below the tank to address the barrel so I will need to remove the tank and possibly the motor so I decided to remove the left hand cover (RHS missing anyway) and kick-start plus gear-change levers in preparation. 

Photos taken of LHS cover and gear change and kick start levers in preparation:

Gear change lever, held with a clamp bolt on a splined shaft. Gear change seems to work well.

Gear change easily removed I refitted the bolt in the lever for safekeeping

Kick start lever held on splines by a clamp bolt. Lever obviously not operating because the cylinder is seized.

Kick start lever easily removed, I refitted the bolt in the lever for safekeeping.

LHS cover badly rusted, held on with 2 countersunk slotted  screws. Front screw shown here.

Removed the two countersunk screws and the cover lifted off.

Under lhs cover, note gear-change coil spring, screws refitted in the case for safekeeping.

In order to remove the motor I will need to disconnect the final drive chain, this is fitted like a bicycle chain with a split link.

Final drive chain, split link on sprocket

I removed the tank, its held on at the front and rear, separate bolt on each side so 4 bolts in all

Rear tank mounting

Lift seat for better access to rear mounting. Store bolts in their original holes.

Rear tank mounting bolts

Front Tank Mounting

I removed the front tank bolts

Tank front mounting bolts removed

There is a short left/right tank equalisation pipe underneath the tank and this also needs to come off. Ignore the Quickly in front- or if you are interested visit my Quickly blog!

Tank equalisation pipe- pulls off.

Once the mountings and equalisation pipe are removed, the tank can be lifted at the rear and tipped down at the front to remove.

Removing the tank

In fact once the tank was off I could get much better access to the seized piston and was able to tap it down with a wooden drift, however this was hard work and I did accumulate a few shallow dents in the side of the bore.

Piston emerging from the bore.

The piston is pretty much seized with the rings fused in place. I will try to replace both piston and bore but if I can't I think both could be rescued (provided I can free the seized rings).

Currently I'm torn between fitting a new cylinder and piston- which is expensive at 225 Euros, or trying for a rebuild and re-chrome on the existing barrel, possibly keeping the old piston but fitting new rings. Obviously an all new replacement would give a pretty new motor and leave me with the existing barrel that I could renovate later... but its all a bit of an expense that frankly I could do without at the moment.
I'm going to mothball this resto until I get some more dosh- be back later so see you then!


Update, I found and ordered a new barrel and piston although I don't currently know if this comes with rings and gudgeon pin but hopefully it will. Thank you NSU Motzke.de By a tremendous stroke of luck I found someone in the UK who had a spare but damaged magneto cover. I've not been able to find this even in Germany so it's a real find here. It will need fixing and probably the services of a Tig welder since this is an aluminium cover, but given the time and cash I'm hoping to get this sorted. When both items arrivedI can say that I'm really pleased with them. The ally case needs some minor dolly work but is vastly better and safer than nothing and the new barrel and piston did come complete with gudgeon pin, clips and rings.

I had to press the pin inwards a little before I could remove the clips.

The gudgeon pin was right in the piston but a sliding fit in the small end Bush. It helps to heat the piston but in my case the pin was seized. I used some M6 studding, nuts, an NSU Quickly gudgeon pin as a press and a variety of sockets to pull/press it out.

I need to do some serious cleaning to this motor and investigate whether I can clean out or check the transfer chamber below the piston before reassembling. I have a Puch Maxi inlet manifold which fits but will need modification and I still need to clean out the carburettor prior to attempting to start the bike!

Update to my parts shopping list: I have obtained the missing engine covers (both sides) as original aluminium parts. I was lucky to get these as even if you do get modern replacements they are fibreglass not aluminium. I obtained these from a guy in Germany who had imported a box of parts from S America where the quick 50 apparently sold quite well. The covers are a little rough but should clean up well.

Secondly, a second guy in Germany has persuaded a company there to manufacture new exhaust downpipes (auspuffrohr in the lingo). These aren't cheap but I have obtained one. I have heard rumours that there are some issues with fit into, and sealing against the head but others have found solutions so I'm hopeful that I will as well. Should add these parts all obtained pre Brexit- they would be a lot dearer to import now.

I've also obtained a gasket set as at the very least I'm going to need a cylinder base and cylinder head gasket.