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Inside the Cucciolo

Philippa Wheeler

How to get there and what to do when you arrive!

The Ducati Cucciolo shares with few other cyclemotors the distinction of a four-stroke cycle.  It is almost certainly unique in that it has pull rods.  As if that were not unusual enough it included a two speed pre-selector gearbox initiated by pedal position for the progressively inclined or, for traditionalists, a visible gear lever (one guinea extra).

If cyclemotors have character, and most enthusiasts would probably concur, the Cucciolo provides it in full measure.  My work notes contain a paragraph headed "Steadfast in Perversity" alongside a photo showing a back wheel bent into a figure of eight.

In the 1960s rampant expansionism led to a second shed for our Midlands family and a late Square Four, a Rudge Ulster, a racing Manxman and a Mk VIII KTT, all for a few tens of pounds in that golden age (don't bother to ask, all but the Squariel long gone).  Myself, I went for a Cucciolo for three pounds ten, which arrived in a box, wooden, courtesy of a steam driven British Railways.  Inevitably, it was minus the crucial bits: tank, cranks and special bottom bracket spindle.  These presumably remained in Fenland, adorning one of those large black upright bicycles that the natives of those parts seemed to ride permanently leaning at 45 degrees into the prevailing wind.  The engine itself adorned a shelf in the garage for the next twelve years.  One day in 1978 it was persuaded to run by the rather hazardous expedient of holding the rim of the outside flywheel against the rotating back wheel of the current Red Hunter.  Another eleven years on, thanks to Michael Jones, then living in Essex and in possession of all the missing bits, it could be put on a bicycle.

First there was a taster for what might be: at one of Colin Packman's Maidstone events Roger Worton entrusted me with his and it was all the impetus that was needed to begin installing Cucciolo 265581 onto the 1933 Royal Enfield.  The Enfield had been bought by my father when it was nearly new, certainly newish, because we were a family who seldom paid full whack for anything if we could possibly avoid it.  It had endured the worst that Hitler could do in the Birmingham Blitz and survived to be serially abused by a variety of cyclemotors and the next generation.  This, with its Power Pak flattened seat tubes, was to be the host for yet another mechanical parasite.

I believe that there exist instinctive mechanics with an eye for mechanisms and capable hands.  Sadly that number does not include me and the words that follow are intended for those of my fellows who learn as I did, the hard way, in the hope that they might avoid the same pitfalls.

It is a fact that very few spares, new or second-hand, exist for the Cucciolo and the missing bits are often difficult to locate.  This is no great problem for professional engineers with well equipped workshops but presents the rest of us with serious difficulties since it is usually the same bits which wear out and we are trying to revive in the 21st century what 1950s owners abandoned as beyond economic resuscitation.  The prospective Cucciolo owner will consider carefully the amount of thread showing above the rocker on the exhaust side, will be suspicious of a flywheel with too much travel either side of TDC on the firing stroke and will marvel at the weakness of the spark (if any) as the said flywheel is rotated, with the plug removed, by a 14mm socket driven by a electric (variable speed) drill.  Further, he or she will draw appropriate conclusions from an alloy crank whose internal toothed ring is pointy in parts and prone to slippage.  Is it not indicative of much pedalling, something no Cucciolo owner would do willingly; it is hard work indeed.

Before fitting my engine, it seemed prudent to take a look at the valves; there did not seem much compression.  It was at this point, 15th May 1989, that a Miracle occurred in South East Wales.  A tiny irreplaceable valve collet leapt into space, heading for the garage floor-and was found again.  Much larger objects had disappeared forever into those spider haunted recesses.  Reassembly completed, would it run?  It would not.  Years of storage had killed the coil.  Exceptionally, an original coil will perform faultlessly; most do not.  They can, of course, be rewound and may or may not perform thereafter, but it is not cheap and there is an inexpensive alternative, recommended to me by Richard Rosenthal, which is to convert to coil ignition.  With a 6V 10Ah sealed battery you can rely on 80 - 100 miles at least, which is enough for most runs.  In emergencies a hand lantern battery will do.  The spark is like forked lightning and a first time start is assured.  In 1989, the choice was to rewind the coil, an eye watering £50.  The long-suffering Enfield had a Sturmey-Archer hub.  A fixed wheel gives engine braking and a less complex starting routine but not the six speeds of a variable hub (three on the SA, times two on the motor).  It may not be well known, but between top and middle on a three-speed SA is a neutral position in which the pedals rotate without driving.  If that position is found and top gear selected on the engine then your Cucciolo can be kick-started with the pedals like a real motorbike.  This is what was done, but in my excitement when it fired up I allowed my trigger finger to relax on the gear change.  This was very unfortunate and had four immediate results: the bike sprang forwards, the back wheel assumed the aforesaid figure of eight, the hub gave up the ghost and I said one of the words my mother so much deplored and which had been learnt in the Air Force.  After that a little clamp was fabricated, but you can of course pedal off with your SA in bottom, engine in top, then when you have achieved flying speed kick-start it safely, valve lifter raised.

Inappropriately, it was on Armistice Day that combat resumed.  The new wheel and its fixed sprocket had cost a modest £23.  With the aid of the adjacent Judges Pitch (1:10 rising to 1:6) sufficient momentum should be provided.  It was, but alas as the crossroads drew nigh the clutch was held out and a few turns of the pedals given to the struggling motor.  It is a pre-selector gearbox and in half a dozen twirls I changed gear as many times and the fixed sprocket, lock ring and all, chewed its way off the nice new hub and sat forlornly on the spindle.  I bore it home, hung it on the garage wall and went racing for a year.  My machine was a Ducati 250.  It had some of the capacity to frustrate of its smaller ancestor, but like the Cucciolo, it came good in the end.

The Technical Bit

Let us assume a complete engine is before you.  You have negotiated successfully and brought your prize home, or perhaps it was a garden shed discovery.  It still happens with cyclemotors but apparently less frequently nowadays with 3 litre Bentleys, which require stronger garage shelves to accommodate.

The basic guide to installing and running is the Britax one available from the NACC library but which does not deal with dismantling.  There are other bits of information in the same resource which are very useful, like the parts list.  The one I have seen is in Italian which, thanks to the Romans, is a lot less unintelligible to Little Englanders than some European languages.  The NACC's Ducati Marque Specialist, David Casper, has an encyclopaedic knowledge of the Cucciolo and its vagaries.

Rotating the flywheel by hand gives an idea of any compression that might be present and the motor's spark checked with the 14mm socket in the drill referred to earlier.  It is usually worth, in the absence of a spark, running a file or emery through the points and trying again.

Specialists like Independent Ignition Supplies will test a coil.  Before removing the flywheel, it is suggested that the valve timing be checked with the rockers set at  .006" inlet, .008" exhaust.  Take a piece of A3 paper and along the long side mark out 36 equal divisions.  This will wrap neatly when cut into a long strip 10mm wide around the rim of the flywheel with 0/36 (360) coinciding at the M mark which is TDC.  It can be secured with Sellotape.  Having checked that both valves are closed it is easy to rotate the crank noting the points at which the valves open and close.  Standard timing is as follows:

Only one of the half dozen engines I have worked on came exactly within these parameters.  It is a good idea to check that the points open coincident with the "a" mark on the flywheel when gapped at .010".  Reset the motor to TDC on the compression stroke, undo the tappet lock-nut and its hemispherical nut to the rocker and put each in a separately marked container.  Undo the acorn nuts at each end of the rocker shaft and note the order of shims and washers and mark the end of the shaft and its adjacent pillar for reassembly.  Examination of the shaft usually shows ridging and wear so if unworn, rejoice, you might have a little used motor or a careful previous owner.  The 4 × 10mm nuts on the cylinder base can be undone and removed, but the barrel may have to be lifted slightly to clear the lowest fin.  Lift the integral head and barrel clear of the piston and lay aside.  The big end can now be checked for vertical play and the piston removed, marking the front inside of the skirt with an F.  The Cucciolo is lubricated by splash as the whirling bits dip into the meagre half litre of oil in the sump and distribute its contents around the interior.  You may even find the odd gudgeon pin circlip in there if you failed to shroud the piston in a cloth.  The valves can now be extracted using the stail of a hammer upended in a vice with the valves supported thus whilst the collars are depressed with pliers and collets extracted.  The presence of an assistant to extract the collets obviates the need for miracles.  It is prudent to consign these parts to the earlier marked containers.  Valves and seats can now be examined; the valves are of very poor material which is why frequent valve grinding in extreme cases takes the seats clean through the iron 'skull' into the alloy jacket beyond.  This is evidenced by the excessive thread showing above the rocker referred to previously.

A bar through the small end eye bearing on two strips of wood bridging the crankcase mouth enables the 14mm LEFT HAND THREAD flanged nut holding the flywheel to its keyed tapered shaft to be removed.  Conveniently, the extractor thread in the flywheel seems to be identical to that of a cotterless cycle crank extractor and the flywheel usually comes quietly.  If the Woodruff key has not quitted the shaft of its own accord, remove it.  You now have a view of all the electrics and just for the record it is worth noting the order of disassembly, though that can be left until later since it all comes off with the lid.  Oil on the electrics suggests the felt crankshaft oil seal has gone and this can be replaced with a modern garter type (15-30-7 6000646 51).

The 'lid' or left hand crankcase is held with a multiplicity of cheese head screws all the same length bar two, which have drilled heads and went either side of the clutch cable recess so they could be wired and a lead seal affixed so Mr Ducati would know if his engine had been interfered with in the guarantee period.  With all the screws removed, the lid can be eased up once the clutch cable has been released from the clutch arm.  The rollers from the outer races of clutch and camshaft can then be heard cascading into the void to join any circlips.  Look for the missing ones behind the gear wheels later.  If you want to avoid a lot of trouble make sure the crank is at TDC and mark the relative positions of camwheel and crankshaft pinion with the faithful Tippex.  Note that the camshaft has an arrow on its periphery whose significance eludes me because I am not an Instinctive Mechanic, and which can be ignored unless the valve timing has been lost.  As you lift out the camshaft, its needle rollers can be heard tinkling in to join the others.  The clutch can then be lifted out as an assembly.  Remove the short push-rod before it disappears and note carefully the location of any shims and thrust washers.  When reassembling it is vital that there is a washer between the clutch circlip and the uncaged rollers of the outer race.  At this point most of the rollers can be retrieved.  It is as well to leave the slip sprocket assembly in place as this prevents end movement on the gear shaft and the puzzling appearance of three ball bearings whose function is described later.  Examine the various gear teeth for rust, pitting or wear.  The clutch inner bearings are the shaft itself, similar to the Mosquito but nevertheless seldom show signs of wear.

Removal of the crankshaft assembly

To remove the crank undo the four 8mm pins having released the tabs securing them and then the slotted plug on the drive side forward of the slip sprocket.  Insert a suitable rod (brass or alloy recommended) and drift the assembly until it can be lifted clear.  Condition of the main bearings can now be considered.  Alpha Bearings of Sedgeley did at one time do a replacement big end and obtaining replacement mains presented no difficulties in recent years.

That, usually, is as far as dismantling needs to go, but for the sake of completeness, I will describe the gear and selector mechanisms.  The gears are selected by the movement in and out of a rod to which is attached an adjustable steel selector fork.  There are three circumferential grooves in the rod in which a spring-loaded ball sits as the rod moves in and out.  The end of the rod is visible outside the case-fully in is bottom, fully out top and halfway neutral.  Unless there is a malfunction with gear selection the adjusters under the right hand hexagon plug on top of the cases should be left alone.  If the slip sprocket assembly (with its left hand threaded peg nut) has been removed then, as described earlier, there is enough end float to allow the three balls to fall out of the gear shaft whose function it is to act as 'dogs' engaging with recesses in the gear wheels.  DO NOT retain them with grease - they need to be free to float in the shaft.  Both first and second gears are so driven and are retained by a circlip.  Also left behind are the cam followers with their support block and outrigger plate; again these do not normally require to be removed-replacement  can be fiddly.  At this point the cases can be washed out or more usually scrubbed out with a solvent because of their treacly residues - a testimony to the parsimony of your predecessors.

Reassembly, as the books say, is in reverse order of dismantling; as famously disingenuous as "owners are recommended to return the unit to the maker's service department...".  However, if you have wittingly or otherwise lost the timing of the valves, read on.

Timing of valves when original timing lost

Undoubtedly there is a quicker and better way, but this seems to work well enough.

  1. Fix a degree disc to the flywheel or use the A3 paper strip method above.
  2. Fit piston, barrel, all rocker gear.  Leave tappets slack.
  3. It is easier to remove the crankshaft oil seal in the 'lid'
  4. Fit the needle rollers to the camshaft.  They can be retained by grease or by the more elegant Casper Method of viscous engine oil additive.
  5. When offering up the camwheel to the shaft, point the lobes towards the crank at which the arrow on the periphery will point to approximately 3 o'clock
  6. Adjust the rockers to running clearances.
  7. Fit the rollers to the camshaft outer race in the 'lid'
  8. Place a ruler on a line made by the camshaft centre and the arrow on the periphery.  Mark the point at which the line crosses the right hand edge of the crankcase.  Number it 1.  This enables you to track the successive trials towards the correct setting.
  9. Fit the lid and secure it with two or three screws.
  10. Refit the Woodruff key to the main shaft and put a dab of Tippex on the outer end (makes it easier to see when offering up the flywheel.)
  11. Offer up the flywheel and secure it with the flanged nut finger tight.
  12. Align 0/360 degrees and 'M' with the timing mark on the crankcase.
  13. Rotate the flywheel clockwise and note the point on the degree disc or scale where the exhaust valve begins to open - it should be 35-45 degrees before 180 or bottom dead centre comes up on the scale.
  14. Then, if the point at which the exhaust valve opens is grossly out, remove the flywheel, take off the lid, lift and rotate the camwheel to, say, 2 or 4 o'clock and try again each time marking a new line on the case and numbering it as before.  I have had as many as six goes.
  15. When the exhaust valve opens and closes at the correct points check the inlet valve timing (standard timing was identified above).  Since both cams are fixed in relation to each other it follows that unless the engine is badly worn inlet timing will be correct also.  In making any final adjustment it is useful to remember that inlet timing accuracy is more important than exhaust since, in a four stroke, the outgoing gases look after themselves.
  16. Mark the correct timing pinion to pinion
  17. Fit both sets of clutch rollers, ease the clutch into position beneath the camwheel, refit the oil seal.
  18. Pour yourself a generous measure of Calvados, light the fire and switch on the telly.

Pourquoi le Cucciolo?

Now that your Cucciolo is back together, rejuvenated and ready for the road it is time to think about getting under way.  In the olden days, assuming a fixed wheel cycle the rider would pedal off and, having gathered speed and in doing so discovered how hard the little Bs are to pedal, would raise the valve lifter, open the throttle a fraction, advance the right pedal and pull in the clutch.  A clunk and a slowing signified gear engagement and releasing the valve lifter the engine would fire up and shudder away in top close to stalling speed unless helped with the pedals.  Slipping of the indestructible clutch is quite normal, while its drag would do credit to a Velocette.  The Cucciolista would, of course, the moment the engine fired advance the left pedal, operate the clutch and speed away in bottom.  It is not recommended to start in bottom unless the motor is thoroughly warm.

If however you have a three-speed hub with that useful gap between middle and top the method described earlier can be used.  Four and five speed hubs are not really robust enough.  A good Cucciolo will develop one and a half horsepower, which is a lot more than most people.

The infamous SW hub with its centrifugal pawls can be guaranteed a short and sad life.  Even the standard three speed AW has a lag before the drive is taken up and a very gentle touch with the throttle is needed.  The ideal is the ASC fixed hub-in Sturmey language three-speed, fixed, close ratio.  These are collectable and thus expensive variations found mainly at those Veteran-Cycle Club jumbles which are a regular closet meeting place of certain of the cyclemotor fraternity, suitably disguised as cyclists.  The ASC gives engine braking as well as nicely chosen ratios and avoids shock loading as the drive is taken up.  A derailleur can also be used, but period derailleurs can be relatively expensive and collectable.  The writer once combined a Sturmey three-speed with a fifties three-speed Cyclo Benelux conversion which was popular with cycle tourists of the period.  This gave 18 gears, which four hands were required to operate.  The six speeds a hub gear gives are more than enough with a bottom gear set that will climb gradients as severe as the Test Hill at Brooklands and on a steep long gradient will see, in the highest ratios with a following wind, a speed I will not strain credulity by quoting.  A more realistic speed is a low revving 30-35 mph on a give and take road.

All this progression is accompanied by the whine and wail of straight cut pinions and a chain that shakes and snatches.  Not restful but fun.  On a good day the Cucciolo feels as if it deserves its status as "the Lamborghini of Cyclemotors" as you overhaul rapidly and leave behind more conventional designs on a cyclemotor run, but keep an eye on the spokes and frame for breakages.  Slipstreaming Hugh Gallagher or Alan Hummerstone on a run is rather like an open practice on a Manx Norton when everybody else is on Bantams.

There is then a magic yet in the name Ducati Cucciolo and some of the latter day aura of that illustrious marque clings to its tiny ancestor.  This brainchild of an Italian lawyer and engineer called Aldo Farinelli was born in wartime Italy at a time when the Germans had outstayed their welcome.  Their contribution is said to have been the unwitting supply of the materials that gave the Little Pup its first bark.  By any standards, Farinelli was a remarkable man and his genius lives on in the survivors of the 400,000 units made.  If you have one of these little gems, count yourself fortunate indeed.

Tailpiece - an update

One of the consequences of bursting into print is that you invariably get feedback or different perspectives.  Having gone into rather elaborate detail about re-timing the engine Hugh Gallagher said "Yes, all very well, and you can no doubt do it that way, but why not use the arrow so conveniently provided by simply rotating the crankshaft so that the arrow on the cam-wheel points to the key-way on the crankshaft when the mesh of the teeth can be highlighted and timing achieved?"  However, it does involve some manipulation to get the alignment.  Both Hugh and Geoff Hudspith of Christchurch, Dorset pointed out the illogicality of valve seat recession with pull rods increasing the amount of tappet thread showing.  Quite the reverse on reflection and more likely, says Hugh, to be the result of missing valve cap(s).  Hugh said he found seat recession unusual but all I can say is that the motors I have must be more knackered than his.

Geoff Hudspith's suggestion for loss of sparks is quite elegant.  "...I got over the problem by stripping off the winding from the pole shoe and winding on a replica of the lighting coil to give in effect a low tension output.  This I led via the points and condensers in the normal way out to an external ignition coil of the type fitted to Raleigh mopeds and Mobylettes.  It fitted very neatly out of sight under the down-tube mounted petrol tank.  Ignition was quite good enough for reliable starting and running..."  He goes on to say that a worn chain-wheel's teeth can be unriveted and rotated to a point where the pressure is least.  He used 1/8" rivets to refix.

Back to Hugh Gallagher: for those unfamiliar with Hugh's oracularity in regard to Cucciolo, he has been running them since the fifties and furthermore is an Engineer, which is more than I am.  Nor am I a roofer but that's another story altogether.  He says that a slipping or dragging clutch could be due to weak springs which he rectified by having new ones made by Paul Savage, Unit 17, Enterprise Workshops, 28 Hemming Road, Washford Industrial Estate, Redditch, B98 ODH; tel: 01527-521666.  Clutch springs are 22mm long with an outside diameter of 12.75mm, wire diameter 2mm and 7 turns.  Valve springs are: Outer - 3cm long with an outside diameter of 14.5mm, wire 1.7mm diameter, 7 turns; Inner 18mm long by 10mm outside diameter with 1.7mm wire and 6 turns.  Accuracy with the clutch springs is important because, if too large, they can break the mazac housing on compression.  Finally, Hugh commented that it doesn't matter whether you use grease or not on the ball recesses in the gear shafts, they work just the same and at least they stay in place.  He feels it is desirable to keep to the manufacturer's design.  Coils can be rewound by Independent Ignition Supplies, Myrtle Street, Appledore, Bideford, Devon, EX39 1PH

The last word comes from Dave Casper who mentions that the little circlips from the pull-rods designed to stop same falling into the case are often missing.  An elastic band or a turn of insulation tape would prevent this.

My thanks too to those who e-mailed or wrote or otherwise told me that they had enjoyed what was written and particularly the people who have been encouraged to tackle their Cucciolos as a result.  That is reward enough.

First published in three parts in June, August and December 2001

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