The Nassetti Sery Racer.



The frame.

We do not know if there ever was  a Nassetti 4 stroke/50 cc. Racer, but we saw, special

cam- shafts  and high pistons for Nassetti, so we think they have tried to increase the

Sery motor. So the idea came up to see if it would possible to turn back the clock 45

years and  make a racer of a standard Nassetti Sery, for real racing. Together with the

Sery motor block, we also had bought a Sery frame. Thus,building a racer seems to be

possible. The intent was there, but, could  we do it?  The only things we had were, a frame,

back-bridge, motor,  a pair of  wheels (not mounted), and a handlebar. Not much to built a

racer from 1955. Several things were clear:the final Nassetti must  look like a racer from

1955, and it had to be safe. Therefore, the spring action had to be good as well. The brakes

had to have enough capacity. There was still one requirement, a lubber of 1.85 m. has to

ride the bike, so it has to fit.


We learned one thing, while building the street Nassetti, first of all gather all the things you

need. Make everything mountable and ready, also the welder works. Then, put everything

together as if its the final mounting. Check everything, to make sure its working well. Look

carefully at your  sitting position, for you can put too much stress on the handlebar, because

the gear is at the handlebar. The foot brake pedal had to be placed in such a way that  you

can reach and  use it without looking. And if everything goes well you can go to the painter

with the things that have to be painted. But that cost a lot of time.



Lets start building, first things first, and see if we can get the Nassetti ready for racing.

The beautiful Italian front wheel turned out to be better than expected.When we found

the correct front frame it was easy to fit after several adjustments. The front frame is

new and (double) oil quenched. To mount the front fork we had to cut the ball head 2 cm.

The front fork is made in Italy. The very small fuel tank fits very well at the front of the

frame, we only had to weld   a small tube at the frame and put some rubber grommets

on it so that the tank can seat on it.



It was different with the back of the tank. This has to be fit at the racing saddle. At this

side of the frame there was nothing to hold on. To resolve this we had to work with all

sorts of shackles. We decided to let the race saddle and the back of the tank lean on

one aluminium sub frame. First we made a  model out of cardboard, put the U form

cardboard on a aluminium plate and  fret-sawed it. After drilling the holes we went to

a sheet metal worker to put the plate in U form.

The results were good.



The results were good. The polyester tank sits on rubber grommets at the back and  front, and is mounted on the frame and sub frame with 4 rubber o rings. So it can by mounted/demounted in a few seconds. Under the tank the bobine (spool) support has been welded at the frame and also the support of the on/out switch. At the cost of  much work by  Rick  the polyester race saddle and the tank connected beautifully to the sub frame. A thick  black piece of Neoprene  was formed into a saddle. The back fork of the Nassetti is built good and stiff, and therefore impossible to see how the fork was mounted to the frame, hinged.  This point has been looked at very well, before being worked on. The original hinge pin, which had the possibility to prevent the side space, has not been used again. After any turn work, we put some strong bronze tubes in to the frame and could the back fork, by means of a new hinge pin, better been mounted.  All the turning points  of the fork can be lubricated by one

grease nipple.



The back fork of the Nassetti is built good and stiff, and therefore impossible to see how the fork was mounted to the frame, hinged. This point has been looked at very well, before being worked on. The original hinge pin, which had the possibility to prevent the side space, has not been used again. After any turn work, we put some strong bronze tubes in to the frame and could the back fork, by means of a new hinge pin, better been mounted. All the turning points of the fork can be lubricated by one grease nipple.he back fork of the Nassetti is small, and there fore it is not easy to find a suitable back nave. And also the nice aluminium back wheel we wanted to mount did not fit.

The only thing we could use was the rim and the spokes. To have a well fit nave we had to make it ourselves. The biggest problem with the Nassetti is to get a good chain line while the rim is exactly in the middle of the fork. Even with the street version, it cost us a lot of trouble. To mount the suitable nave we had to turn  a flange out one piece to make the nave smaller, and to put the chain tooth wheel  on the chain line. To ensure that the flange will be straight and centered, it has to stay in the lathe, for an error of 0,1 mm, could make a swinging wheel, as well as in the Y and X cinder . It cost us 2 days.


It is always exciting  to see if the product fits. Luckily the flange and chain fits well. A  secondary advantage of this back cinder is that it is mounted with a sting cinder. And  so the chain strain will not be mend  by demounting  the back wheel. By putting the Nassetti   on the  wheels the sitting position and the places of the foot support, could be fixed. One thing  was clear the Nassetti is small and low. To put the  foot support on the right position you need 2  strong  8mm aluminium plates. Left and right are not  similar, even here we have ensure that the both plates were placed at the same time. The security bolt of the left foot support is also the flange point of the brake pedal. The adjustable brake cable is also mounted there. The brake pedal has been made  to measure and operates  a standard back brake cable

( kreidler). The plates are connected right at the front of the back wheel. This unit is mounted to the frame with 4  m8 bolts. Because the sitting position was put to the back, it turned out that the backspring action was not strong enough. So it had to be adjust. Two double dimmed agons have to do the trick. Just now, at the test drive it would turn out if they hold. To mount the motor block cost us one our. The Nassetti frame and motor block used here are both new, but they are from 1955. The Nassetti racer motor block has to  be put into the frame with force. But the motor has to fit scull free and has to spring  in the anti tremble tubes. After an hour of filing and shaping and

fitting the block slid smoothly into the frame  and we could tie the three bolts. These bolts are not tied strongly for they only have to hold the motor in place. The female screws are extra security against trembling. So the anti trembling grommets are used optimally this way.

Picture 1 reflects nicely the state in which the Race Nassetti is. Now  we can finish the parts permanently together. If every part fits after pre-mounting we can send them for painting and enameling. In this case all the parts are sprayed. Alas , the exhaust is not yet chromium plated, so you can still see some welded spots. On the picture you cannot see the leading for the cables , which is not yet mounted. The handle bar was also not correct and was replaced later on. Here you see no front mudguard , for I did not know that it was required. Before you can enter the racing circuit, the motor has to have an inspection. Not only for safety, but also on looks. This machine is a 1955 model, so I am not allowed to use disc brakes or digital revolution counter.


Picture 2.


For safety it is allowed to mount modern springs (antique look) and tires.It is always forbidden to drive without an approved helmet. But you can drive with a classic look outfit. I call it the seal outfit. Well, let us see what the painter  has done with the bike. It is strange to build a Nasetti racer after a year of preparation, as if it is a common matter. I have forgotten to make

pictures of the different mounting phases. In the meantime the inspection demands came, and now we could apply it to the racer. Not only safety but also the milieu has been thought of.All the cables have to be soldered, handles and steering wheel ends have to be rounded off etc. etc. Every  bolt/female screw; for example, the front/back wheel had to be secured separately. Even the hinge points of the back fork were taken to a second level of security. All the points at the motor block have to be especially secured when there is a possibility of leaking oil . A small but important detail are the air valves of the tires: they have to be protected with valve caps

(not plastic) with extra rubber rings to prevent that the tire going flat suddenly from a defective valve. The ventilation of the petrol-tank and carter had to be made in such a manner that none of the contents could drop on the street. It seems a bit exaggerated, but nobody likes to have oil or grease on their tires. And in the second place, milieu stresses the bike in  mechanical sports. The tires are critical. Every owner of a bike, no matter who, wishes that his bike was that well looked after, after every race. Before every race, the bike has to be inspected, even if you only have had a short race, for example, 5 km. Who is who given an example.


Picture 2, shows how the Nassetti racer looked at his first test. But that was after I had dragged the racer down two stories. Now I could try the motor block (1955), which was as new and had never been used. The algorithm for a 45 years old Nassetti is: put 500 cc oil in the motor and fuel in the tank. Open tap, push 3 times on the choke. In the case of the racer, put the gear in the second position. Develop speed, release the clutch. The motor runs directly. And just drive away. I was surprised it worked at once. On a beautiful day in spring 1997 I tested the racer on a closed highway in the neighbourhood of Ermelo. 500 meters to and fro, without any curves. Nice but not satisfying. Besides, the motor was that new, so that driving it with full power would be stupid. But racing season approaches. There still were several obstacles to take, but it cost money. An empty purse is not a good base. I needed a new outfit , helmet, sponsor , etc. I still have my racing boots.


The Nassetti Sery racer

anno" to day".



Nassetti racer 1955.


Dellorto 16mm 4stroke race carburateur.


The bigger crankcase.