Real Classic

A RARE DUCATI 76

John Lay wasn’t looking for another project, but one found him anyway. Say ¡Hola! to the Ducati which was built in Barcelona…

- Photos by John Lay, Rob Klootwijk and Chris Haggis

John Lay wasn’t looking for another project, but one found him anyway. Say ¡Hola! to the Ducati which was built in Barcelona…

Over the years I’ve found some machines because I went looking for them. Others have found me. Thus it was at the Kempton autojumble, before lockdowns started. I was helping on my mate’s stand, looking at the opposite stall where a handsome Ducati was displayed. The owner started it up and it sounded as good as it looked. I just had to go and have a look, as you do. Just as a punt I made an offer, not expecting it to be accepted… and it wasn’t so I thought no more about it.

People stopped to look at the 350 but no one bought it. While we were packing up the owner walked over to say he might consider my offer after all. Later that week the phone rang. My wife answered.

‘It’s Chris from Kempton. I’ll accept the offer.

Can I deliver it Saturday?’

Ever had that sinking feeling? I promised to get rid of some of my existing bikes and peace was restored.

After the bike arrived, it was time to see just what I’d bought. The previous owner had clearly spent a good deal of time and money but there were still a few issues to sort out. The first surprise was that the bike was not made in Italy but Spain by a company called Mototrans. Never heard of Mototrans? Me neither, although given the numbers of Italian-derived machines built in Spain it shouldn’t have come as a surprise.

Maquinaria Y Elementos de Transporte SA was formed in 1958 from two companies, Maquitrans (who made and maintained trolley buses), and Clipper, a Ducati importer. The Mototrans factory was situated at Barcelona. The first model made

entirely in Spain was the 125S, and thereafter the range of four-stroke machines closely followed that of the Italian factory. During the 1970s Mototrans even supplied engines to the Italian factory. Production of the bevel singles ceased in Italy in 1974, but Mototrans continued building them, producing Spanishdes­igned models called the Vento (Wind) and Forza (Force).

In 1978 an agreement was reached between the Banesto Group, who by then owned both Mototrans and Sanglas, and Yamaha. Finally, the business concentrat­ed on just importing Yamahas into Spain, and the other businesses were closed in 1983 / 84.

Looking at my 350, I soon discovered that the clutch slipped. This made it difficult to kick over compressio­n, something that Ducati singles have a lot of. The steering head was bit slack, the brake return spring and speedo worm drive were missing, and the front tyre was fitted back to front.

First job: the clutch. Despite the adjusters at the end of the clutch cable being wound right in, there was still no clearance at the clutch actuating arm. I removed the oval cover plate to give access to the adjusting screw in the clutch pressure plate, and corrected that. Although the correct adjustment improved things, the clutch still slipped. There was nothing for it, the clutch cover had to come off.

For this, you need a special tool which of course I didn’t have. Some people say you can use a claw hammer instead – by inserting the claw into the clutch inspection hole and levering it against clutch body. That sounds like a bit of a bodge to me. If there is a proper tool, then it’s best to use it.

I needed to undo the large brass plug in the centre of the case. This had a 14mm hexagonal hole in it. I didn’t have the right size Allen key but found a bolt that had just the right size head to fit snugly into the plug. I drilled and tapped in an odd bit of bar, screwed the bolt in and then brazed it into place. The resulting tool worked a treat – once a piece of two foot tubing was put over the end! Did it really need to need have been done up that tight?

That extracted the plug, which still left the eight 6mm Allen bolts around the case perimeter. They wouldn’t come out, not even with the two foot tube over the end of the

key. In the end I needed an impact ratchet gun, set at 200NM. I’m amazed that bolts of that fine a thread (1mm pitch) could be done so tight without stripping out the aluminium of the crankcase.

With the centre plug and all of the Allen bolts out, the outer cover could be removed with that special puller. I found an odd piece of 25mm hexagonal bar, turned down and threaded it 22mm x 1.5mm (the same as the brass plug). This in turn was drilled and tapped to fit my slide hammer. With the slide hammer in place it was a simple matter to pull off the cover. It needs to be done this way because, unlike most clutch outer cases which almost fall off once all the screws are removed, this one has an outrigger bearing for the crank carried in the cover itself.

With the puller in place it could be removed – not forgetting to drain the engine oil first. The oil on these machines is common to engine, primary drive, clutch and gearbox. A few taps with the slide hammer and the cover popped off with no further ado.

With the cover off, the clutch could be easily inspected and attended to.

The clutch itself was convention­al enough; six springs carried in cups inserted into the top pressure plate, held in place by cheesehead­ed set screws and a flat washer. Once these are removed the springs can simply be pulled out. A new set of springs came with the bike, but were different to the original springs. The old springs were around 3.5mm shorter and made from heavier gauge wire. In theory they should have been stronger. However when inserted into their cups they barely stood level with the pressure plate. As a result they were under very little preload when the fixings were tightened up.

I learned later that spacers can be used to increase the preload, but care needs to be taken not to make the springs coilbound when operating the clutch. I took the opportunit­y to inspect the condition of the clutch plates for any obvious signs of damage, warping, etc. This engine was supposed to have covered less than 400 miles since a rebuild so I didn’t really expect there to be any issues, and there weren’t. I put the whole clutch back together with the new springs, refitting the retaining screws, and rechecking the lever adjustment. Success! I could stand on the kickstarte­r against the engine compressio­n without slipping. So I

replaced the cover – but not doing up the Allen bolts nearly as tight.

The previous owner had warned me about the slack steering head bearings which were ‘bedding down’ as he put it. This was simple enough: slacken off the nut on top of the fork yokes and turn the much larger nut underneath to take up any movement. I didn’t have a big enough spanner for this, so I modified an old push-bike spanner – the type that look as though they were stamped out of sheet steel – by grinding out the jaws a little. Once the top is undone the large adjusting nut moves easily enough. I even remembered to check it all again after the top nut was tightened up once more just in case anything had shifted.

The back-to-front tyre was marked ‘front’ with an arrow showing the direction of rotation, so it should not have been difficult to get it on the right way round. Perhaps the wheel was the opposite way up when being fitted? It wasn’t a big deal to correct, apart from the usual struggle removing and fitting tyres.

Taking the front wheel out allowed clear access to the speedomete­r drive. This item was missing when the 350 had been bought by the PO. He had, at considerab­le expense, obtained a replacemen­t from Italy… only it didn’t fit. Not surprising really as the wheel was made in Spain.

The front right-side ‘brake’ is just a dummy, it only carries the speedomete­r drive. This item consists of a gearwheel fixed to the wheel hub which in turn drives a worm mounted on the plate, just below the mudguard stay. The worm which came with the machine would not engage with the gear mounted on the hub. A number of nicks and bruises on the worm showed where someone had tried and failed to make it mesh. The angle of the worm teeth was simply incorrect, which left me with the problem of finding the right one.

I reasoned that the best place to find parts for a Spanish-built wheel was Spain, and searched the Spanish ebay site. I found a back plate complete with its worm and from the photos it looked as though the worm teeth were indeed cut at a different angle. I took a chance and bought it – and was it the right one? Yes!

With the addition of a small thrust washer it all went back together as it should. The gear and worm were given a helping of grease and the wheel put back into the forks.

Then a couple of odd jobs. When removing the nearside footrest, I found that there was not enough room to get a ring spanner or a socket onto the fixing bolt head, and only with difficulty an open-ended spanner. The bolt head itself was somewhat damaged, showing that someone before me had experience­d the same problem. So I reduced the head from 19mm AF to 17mm. That meant a 17mm ring spanner would fit with adequate clearance.

Some parts were ordered from Classic Ducati; the missing brake return spring, a new oil filler cap (the one with the built-in dipstick), and a pair of seat trims. The brake spring soon arrived and was fitted… which revealed that the brake light switch was faulty: something else to fix.

My initial to-do list was complete, so I turned my attention to the things that weren’t exactly ‘wrong’ but which I didn’t much like. Although it was now possible to kick the engine over compressio­n, this was rather hard work. It needed was a valve-lifter, normally fitted to the 350/450 models. It sits on the front rocker box cover where a boss is cast into it for that purpose. On my machine the boss was there all right, but it wasn’t drilled and the lifter assembly was missing. I could drill it myself or find the right one – the correct item turned up on Spanish ebay site for not very much money. If finding the cover was quite simple, then finding the

lifter assembly proved to be the exact opposite. Searching online and contacting various Ducati specialist­s here and abroad failed, so I decided to make one myself. I knew what it looked like, from photos and pictures in the parts book, but I didn’t any dimensions. So making one involved a fair bit of guesswork plus cut and try, fit and try again.

The body was made from 19mm AF hexagon, the side plates and operating lever from 20mm x 3mm flat, and the whole thing was brazed together. I took some time to determine the correct length of the lifter pin as there was not a lot of clearance between the cover and the rocker arm below it. I learned later that there were two different assemblies depending on whether the rocker arm is of the solid or adjustable type; the difference being the length of the lifter body and the length of the pin. My engine’s rockers were of the adjustable type, meaning that both the body and pin are quite short. It was a case of trimming the pin and body a little at a time until I got it right.

Once the dimensions were correct, I fitted the cover to the engine to ensure that there was clearance between the operating pin and the rocker arm – and to check that it actually did what it was supposed to do. Satisfied that everything was working as it should, the mechanism was given a coat of Hammerite and a stronger return spring underneath the operating pin to ensure that it lifted clear of the rocker arm when not in use.

The original Ducati handlebar set-up used a twin pivot mounting for both the clutch and valve-lifter, missing from my 350. But the original was quite a long affair, quite unlike the more normal ‘trigger’ type. An old brake lever was used instead. I think the long lever was probably needed as a fair bit of pressure is required to depress the twin hairpin valve springs.

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 ??  ?? Left: The Ducati as found by its previous owner
Left: The Ducati as found by its previous owner
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 ??  ?? Above: Here’s the Duke before John got to grips with it, propping up the previous owner’s fence…
Above: Here’s the Duke before John got to grips with it, propping up the previous owner’s fence…
 ??  ?? John’s home-made tools. The upper undoes the 350’s centre 22mm plug, and the lower is an adapter to fit his puller
John’s home-made tools. The upper undoes the 350’s centre 22mm plug, and the lower is an adapter to fit his puller
 ??  ?? Right: The right side of the front wheel looks like a brake plate but that air scoop is just a dummy. All it carries is the speedo drive
Right: The right side of the front wheel looks like a brake plate but that air scoop is just a dummy. All it carries is the speedo drive
 ??  ?? The two speedomete­r drives, the Italian one (top) and the Spanish drive (bottom). Note the difference in length and the helix angle of the teeth
The two speedomete­r drives, the Italian one (top) and the Spanish drive (bottom). Note the difference in length and the helix angle of the teeth
 ??  ?? The home-made slide hammer / puller constructe­d from a length of ½” rod and an old cast iron hand wheel. Adaptors were screwed on to the end of the rod
The home-made slide hammer / puller constructe­d from a length of ½” rod and an old cast iron hand wheel. Adaptors were screwed on to the end of the rod
 ??  ?? Above: The original clutch springs
(left) and the new replacemen­ts (right).note the difference in length…
Above: The original clutch springs (left) and the new replacemen­ts (right).note the difference in length…
 ??  ?? John’s first attempt at making a valve lifter – by eye, without knowing its correct dimensions. This time, the lifter body and the pin were way too long
John’s first attempt at making a valve lifter – by eye, without knowing its correct dimensions. This time, the lifter body and the pin were way too long
 ??  ?? The home-made lifter assembly seen from the inside and then in situ, with the anchor for the operating cable fixed under one of the cover fixing bolts
The home-made lifter assembly seen from the inside and then in situ, with the anchor for the operating cable fixed under one of the cover fixing bolts
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 ??  ?? The valve lifter finally in place on the cover, after several attempts to get the body and pin length correct
The valve lifter finally in place on the cover, after several attempts to get the body and pin length correct
 ??  ?? An original valve lifter assembly, not so different to the one John fabricated, but with a longer body and pin for use with solid rocker arms
An original valve lifter assembly, not so different to the one John fabricated, but with a longer body and pin for use with solid rocker arms
 ??  ?? The Mototrans 340cc 28bhp single was available in several guises; Sport, Road and Scrambler
The Mototrans 340cc 28bhp single was available in several guises; Sport, Road and Scrambler

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