A  History of Classic Racing  50cc Motorcycles



This story is from Pietro Regazzetti, a true Aficionado of the Guazzoni and is formed from notes, forum entries and other comments I have collected over the internet. I have amended where necessary and translated into English. Any errors I apologise for.  I have tried to display it as a story of the restoration.

Looking at some unmistakable details of the frame and from the type and mounting of the engine I would assume that this motorcycle was assembled in 1971, The motorcycle is in good order for the year with the exception of the saddle, which is the style of a previous Matta and the expansion chamber, which I will take away during the restoration, as it is of the dell' ingranaggino design.

I obtained the bike about 10 years ago by my purchase from the person who had custody of it and all the material. I decided then that the "sporting" modifications had been made at a time which was no later than 1976.

For what ever reason the bike has a rear wheel of the dell'ingranaggino design with a Dunlop Racing tyre of the KR type, 1976 and in excellent condition and as I have previously said a dell'ingranaggino expansion chamber. The front wheel has an interesting hub. It is a Grimeca four cam, ventilated unit of 150mm diameter. 

The engine is a four-speed unit and I note the use of a wrong series carburettor at 20mm. This jars a little with the rest of the bike as with a normal engine of 1971 it definitely could not run. I think those parts were assembled to complete the appearance with the hope to sell the bike as a used racing special. 

I'm torn in my decision on what to do with this restoration. I have everything I need with the material and parts to re-make it as standard, as it was sold. I believe that I will do this, partly because the Cadets of 1967 already have a model restored while a 50cc model could be use in some other events. I miss some pictures of what this bike looks like after 10 years under a blanket in the corner of the workshop.

This model is the latest version for the road going "Matta" and that's what I will restore it as.  In the company this model was simply called the "Sport " to distinguish it from the "Matacross". On the market and officially, even on the brochure it was was called "Matta". This is a big restoration and you must wait, it will come but give me time, I want it back as it was and so it will take time. Unfortunately this bike was painted with a broom, which is a great shame as the tank, which originally had a good, gel coat finish and was left natural, has been painted red and it looks evil !!

I have already made some tests and I may not be able to bring it back to the original gel-coat colour of white as time has caused damage but  fortunately the red paint was a solvent based paint, thank goodness !! With a little thinner and a lot of patience I should be able to get back to the white and see if it can be salvaged. I hope so.

If you look at the wheel you will notice its original look with the decals of "Sanremo" undamaged. I want to use the original decals where ever possible and so will put the original box irons, chain guard, headlights (these are included with the project). The only item missing from the bike is the is the short-circuit button. I think the exhaust system is mount incorrectly and I will change this as it looks wrong and the noise it makes would not be accepted.  

Here I have done a little bit more work. I have put the rear mudguard where it should be positioned (it will be painted) and done tests on the paint stripping for the tank. As I looked at it I thought it would be a hard job because there was always a red even after a lot of rubbing and I thought I would never achieve the white.  Finally the white gel-coat started to show instead a layer of the white epoxy paint primer, that was thick under the red and then finally the original white gel-coat. So the operation will be longer than I at first thought especially because of the  epoxy primer, I do not know if I can save the original white and have only a shiny finish but I want to try as I hate motorcycles that look "swollen" with heavy paint and glossy coating. They  were not so when the bike was manufactured! Then, as is my practice, I have dedicated myself to the GS 125 air filter (obviously Guazzoni).


I have been asked the question, Peter; when you have time can you take a picture of the underside of the Tank?  Here are two pictures of two  tanks.  You will see that the second picture shows a widening at the front of the tank. This is essential for a Matta, but not on a standard motorcycle. It seems to me that these tanks were made by Ballanti of Bologna (or Bertolani of Milan?).

If the saddle is that of the Matta, then it will be tough to find a  replacement one. I do have racing saddles which are in good shape but not of this Guazzoni era unfortunately.  The frame is good, it is not yet clear whether or not it is repainted but with care and tenderness I should be able to preserve it.

After several engine starts and discharge tests, to prove the exhaust system usable, I will keep the original Guazzoni black finish, dell'ingranaggino expansion chamber.  The look is good and the sound even better. I can assure you that among the resonance of the head, the disc whistle and expansion chamber, the engine makes a "distressing" noise. I can still hear the sound of my friends dell'ingranaggino, even though we turned down the engine, it would sound like a scream when it peaked at 14,000 rpm and had amazing speed. This restoration will be much quieter, but not that much.

I have pursued the paint removal work and it has taken two hours for two small areas, These are the two dimples in the picture. In answer to a question I received I suspect that your tank is different, and you need to verify the distance between the two dimples, the first being for the resting pad and the other being the fuel filler recess. as shown in the picture. If the distance between the two is 47mm, then it is the dell'ingranaggino tank.

Work is continuing, I have conservatively restored the swinging arm suspension units. I basically just cleaned them and tested their movement, which was OK. Everything on them is in place and the photos are a before and after. The chrome on the springs was in good order and did not need re-plating.

The front end, for now I will leave it as a "racing" modification and if I need to make it original, I can just change the wheel. The rear wheel with the Dunlop KR on it was on the Cadets, and so it can stay here. I will not open the engine as it feels OK as I turn it and it looks okay. If after testing it shows a problem I'll just strip it and replace any item that need attention. 

Cleaning continues, but it's hard, I do a piece at a time using the small pan cleaning sponge with non scratch pad. This pad is very gentle on the tank and removes the paint with care.  

I will definitely make a study of the Guazzoni tanks among my acquaintances to see if there are two types, that is, one with the dimple closer to the cap or whether it was made as a way to differentiate it from that of the Guazzoni MATTA. Definitely the colour, the cap and pommel fixing points are not Guazzoni.

Work continues at a fast pace, I have finished removing paint and the tank is dry, I have not found any repairs that need doing which id good as this is a question that you have to ask when you are going to re-paint an item. To have a tank leak after the finishing would incur more cost and may destroy the work you have done in preparation.

On the right side of the tank there are sketches that have been scratched into the gel-coat, you can see written the long name of Guazzoni but with paste polish I have reduced the damage and after painting it will be mainly covered by the original decals that I fortunately have.

Talking to a lady member of the forum has raised a doubt. She told me that her Guazzoni tank (Immaggino Canary) used with current gasoline has started losing petrol. My tank still in the mix that was made 40 years ago and with old leaded petrol did not lose any fuel. Since those years I have made the internal surface of the tank Ethanol safe using an appropriate treatment. Tomorrow the weather will be shiny and I can put the decals on the sides. I think is good.

I have placed the two models of the tanks close together and they tell their own story. These pictures were taken Saturday by Ruggero and it is clear that the lady's tank (the dirty looking one) pictured above my one is not Guazzoni. Apart from the difference in height and width the most obvious thing is the angle of the side which is far more inclined than on the Guazzoni. I think, however, that the manufacturer is the same (presumably Ballanti of Bologna). This is clear both from the shape, the cap that is identical and fixing system. You see here the photos of the two tanks.

After the painting and polishing, the tank is finished apart from the taps.  These are now fitted and the tank looks complete. tank, It was a tough fight and a lot to learn but finally I did it and I think the result is good, I have original decals in the true sense of the word. These are not play transfers or facsimiles but the correct water-slide items. When I attempted to put these decals on I aged about 3 years and the anxiety! It is a fact I made a mistake and remove the transfer immediately and threw it away because I had come off the sighting line a little bit. Some hill I said and also a big "Wow". I do not have many transfers and they will end soon. Amazing how after more than 40 years they are still functioning well, if applied with the trick that been taught to me then. I wanted to place it on the bike, to see how he looks, After this I changed the rear wheel from the dell'ingranaggino and put in another that conformed to the correct model. Now I must find the correct seat and paint  front mudguard and seat white and then the  chassis is finished.

The work continues. I have just returned from a short 4-day tour to get away with the good wife. Out in the workshop I noticed that the front tyre was fairly well worn and cut, where can I find a striped 2X18. Are there remakes available? someone come back to me. I can place the saddle of a Matta 2nd series on the bike which is the current one. However I would have to use the white paint when I make it match the colour scheme. Questions and at the moment no answers.  In the Meantime, I opened the cylinder head and yes it is a 50cc and not a 60cc Cadet. It is in good condition but the dell'ingranaggino head is not right and so I will get the longest studs possible and put on the head of a Matta.

Both the 50cc and the 60cc have Asso Pistons with two segments at the base to match the transfer ports. With the first  piston it is for the 50cc and this was special. It has an auxiliary transfer window and low depth grooves around the piston to give better lubrication. The other is a more standard piston, still with an auxiliary transfer window but with a smooth mantle. After some ruminations I decided the first piston was better and here is the engine closed with the correct head. 

Continuing my story of the Guazzoni. I had just got home and I could not resist going to the workshop and I leaned on the bike to see how she looks. Then I studied to see how to restore it further. It has some problems but you will see that I have ways of getting over them. I will now try the new bolts and then will paint where necessary with the white. I will go with a gel-coat finish on the tank as at least it is original. I like to think that perhaps I can do the same with the seat that I've seen nearly 40 years ago when I mounted a few on the Matta sold in that period. I will need to work on the seat to get a good restoration.

Slowly but surely the works continues. I have repaired the saddle, with fibreglass where necessary and had some problems with the preparation and painting. I must say that seen through the eyes of 1970 it was just a nice 50cc, even a bit forward for its time as both chassis and motor solutions went together to make a good complete image, pleasing to the eye. But I'm biased

A short clean and polish on the covering and the seat begins to take shape. After carrying out a lot of research I have finally managed to find the pins for fixing the seat, These replacements I have found are exactly the same as the original ones! I glued the cushion and cover back on the base and put in the pins. I would say that the result is very satisfactory, although a there are few small imperfection in the paint work.

I would say that the result is more than satisfactory. You may make any objections on originality but remember this is a Matta Sport of 1971-72 which when sold went out with Ceriani 30mm front forks, which were non-compliant with the version number of this model of the motorcycle and there are some other details, a little incorrect but strictly created due to age and coming from Guazzoni. These differences are: - The bike is with ventilated front wheel hub from Grimeca in 150mm diameter and 4 cam, Matador racing handlebars and controls, dell'ingranaggino expansion (also emblazoned) chamber, 60cc head and consequently a Dell'Orto MA 20mm carburettor (the original is Dell'Orto MA 18) the rest is as the factory did it including the decals on the top box and the tank. Note the odometer, The missing unit has been replaced with a Rolle again, with zero km.

This is the end of he project and I must say that I am delighted with the look and and finish of the machine. It truly represents a Guazzoni Matta of the period and I feel good in displaying it at shows. 

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