Le 31-12-69 : Scooter RUMI

Objet: joindre un correspondant
De: Claude Crochard "crochard@univ-metz.fr"

Bonsoir,

En cherchant tout ce que je peux trouver concernant le scooter Rumi, je suis tombé sur votre site et plus particulièrement sur une communication signée bideaux.gerard@neuf.fr
Merci d'avance.
Gérard BIDEAUX
ps: Photos de mon Rumi

J'ai essayé de communiquer avec la personne, mais c'est impossible (vraisemblablement pour cause de changement de fournisseur d'accès). Il est possible que vous ayiez une adresse qui marche pour cette personne, on ne sait jamais....
Si c'était le cas, pourriez-vous lui faire suivre le texte suivant (qui m'a donc été retourné), accompagné du fichier que je vous joins. Ou, à défaut, me fournir cette nouvelle adresse. Ou alors... tant pis.

Merci pour ce que vous pourrez faire.
Bonne soirée

Bonsoir,

Je viens de trouver le site "Lieux de mémoire" dans lequel vous dites être à la recherche des données de carburateur du Rumi. Peut-être n'en avez-vous plus besoin, car je ne sais pas de quand date votre texte... Néanmoins je vous joins une copie (en anglais, mais pour les chiffres ça
ira...) que je viens de me faire pour moi et qui pourrait vous aider.

La nostalgie étant la plus forte (depuis bien longtemps...) et la retraite pour l'an prochain...., je viens tout juste d'acheter sur internet le même RUMI que j'avais du temps de ma jeunesse, sauf que celui-ci est en morceaux et en piteux état... Avant que le désespoir ne m'abatte dès la vue de l'engin (ce sera pour le WE prochain), je surfe tant et plus et suis preneur de toute adresse, conseil, ficelles etc...
Comme je vois que vous vous êtes trouvé à peu près dans le même cas de figure que moi, je serais très heureux de bénéficier des conseils que vous avez pu tirer de votre propre expérience de réhabilitation.
Personnellement, ce c'était pas en algérie mais au Maroc que j'étais et mes parents me l'avaient acheté d'occasion dans les années 60. Je l'ai conservé jusqu'en 1976, à mon départ pour la France et, n'ayant le droit d'emmener qu'un seul véhicule, je l'ai échangé avec un ami le jour du départ, contre une galerie pour la voiture nous emmenant (avec femme et enfants) par l'Espagne....
Depuis, je ne me suis jamais remis d'avoir bradé ainsi un tel souvenir de jeunesse ! J'espère que j'arriverai à "panser un peu les plaies" en reconstruisant ce puzzle-rumi...
Bonne soirée


****************************************************************************
Monsieur Claude CROCHARD
UFR Sci.F.A. (Sciences Fondamentales et Appliquees)
Universite de Metz - Campus Bridoux
Avenue du general Delestraint, 57070 Metz FRANCE
Tel/FAX = 03 87 37 86 77 - Email crochard@sciences.univ-metz.fr
****************************************************************************
Technical info
Contents:
Engine Specifications Engine Strip Down Questions and Answers Gear Selection problem Solved (Jumping out of 1st gear) Carburettor/Ignition setup these are the parts that make up the Rumi scooter. This diagram shows the rear section to be one piece, this was correct for very early models later models had a split rear section just behind the front seat. The panels were constructed from die-cast aluminium and simply bolted to the engine to make a very rigid structure.
To highlight how tough it is I witnessed my brother being hit side on by a car doing some 30-40 mph, my brother was thrown clear without injury (thankfully), the Rumi was also unharmed. He picked himself up and continued his journey to work.
(True story). This is the 125cc power plant used in most of the Rumi range. The 125cc two stroke twin engine only differed in various models by its power outlet. Higher power was achieved by increasing inlet/outlet port sizes, larger carburettors and high compression pistons. The engine was capable of producing speeds above 100mph in race form, not bad for an engine designed shortly after the 2nd world war. Here we see the engine installed into the scooter frame.
Clearly visible is the forward angled kit start arm and the rocking gear change lever.
The gears are selected by toeing the front pedal section and heeling the rear pedal section, 1 toe and three heel, (1 down and 3 up). The carburettor shown here is of the Tipo sport model, it is a 22mm Dell'orto.
Not shown here is the unusual rear brake pedal which is located on the other side of the engine.
The brake is operated by the riders heel.


Engine Specifications
Formichino Tipo Sport Bol d'or Junior Gentleman Junior racer
Two stroke 125 twin
6.5 hp at 6500 rpm
C.R: 6.5:1
Lubrication: Petroil
Carburettor: 1 15mm Dell'orto
Top Speed: 45-50 mph.

Two stroke 125 twin
8 hp at 7200 rpm
C.R: 7:1
Lubrication: Petroil
Carburettor: 1 22mm Dell'orto
Top speed: 65-70 mph

Two stroke 125cc twin
8.5 hp at 7200 rpm
C.R: 7:1
Lubrication: Petroil
Carburettor: 2 18mm Dell'orto
Top speed: 70-75 mph

Two stroke 125 twin
9hp at 7300 rpm
C.R: 10.5:1
Lubrication: Petroil
Carburettor: 2 18mm
Dell'orto
Top speed: 80-85mph

Two stroke 125 twin
9.5 hp at 7500 rpm
C.R: 11.5:1
Lubrication: Petroil
Carburettor: 2 22mm
Dell'orto
Top speed:95-105mph

Carburettor/Ignition etc
FORMICHINO TIPO SPORT
CARBURETTOR
Main Jet -----------------45-60
Atomiser-----------------262
Needle-------------------C7
Notch Position----------Middle
Float Weight-------------7.5gr
Needle length -----------
Throttle Slide-------------55
Idle Jet-------------------45
TO RICHEN MIXTURE
Screw adjuster clockwise (inwards)
TO WEAKEN MIXTURE
Screw adjuster anti-clockwise
(outwards)

IGNITION TIMING
From mark (A to Mark O)
on flywheel---------------30mm
A= Advance (points just open)
O= Points fully Open at TDC
TO ADVANCE TIMING
Rotate back plate Clockwise
TO RETARD TIMING
Rotate back plate Anti-Clockwise
Spark Plug Gap------20-22 thou
----------------------0.5-0.56mm
Points Gap-------------12 thou
------------------------0.32 mm
Crank case Oil Capacity 2 ½ pts
Oil Type----------------SAE30
Petrol/Oil mix standard oil 20:1
Synthetic----------------25 to 40:1

TYRE PRESSURES
Front----------------------18Lbs
Rear-----------------------22Lbs
With Pillion
Front----------------------22Lbs
Rear-----------------------28Lbs

CHAIN SIZE: 1/2" X 3/16"
98 Links

Main Jet---------------100
Atomiser---------------265
Needle------------------E1
Notch Position---------Middle
Float Weight-----------6.5gr
Needle length ----------62mm
Throttle Slide-----------70
Idle Jet-----------------45
AS FORMI

AS FORMI

From Mark (A to O) ----25mm

A= Advance (points just open)
O= Points Fully Open at TDC
All below as Formichino

One of the many things that Rumis are renowned for is the ability to balance an old threepenny bit on the crank case of the engine and rev the engine. The engine runs so smoothly at even high revs which allows the threepenny bit to remain standing upright as seen by this picture.
The test is simply known as the Rumi threepenny bit test.
The engine is almost vibration free. RUMI 125cc TWIN ENGINE STRIP DOWN (Not for the faint hearted)

The engine has been washed down and clamped in a vise. Remove carbs Undue the cylinder head nuts and remove
the cylinder heads Remove the timing cover bolts, remove the flywheel by removing the castle nut by using the special tools Remove the flywheel from the crankshaft using a puller Now simply remove
the cylinders being careful not to damage the pistons.

Now remove the gasket if it is in good condition it can be re-used. be sure to place it the right way round. Timing side.
Mark the position of the mounting plate with a punch before removing the the plate. The timing plate is held on by three screws and can now be removed. Now remove the final drive sprocket, it must be locked before releasing the nut. Use special tool if available. Remove the sprocket from the splines. Check the condition of the splines.

Remove the nine slotted screws holding on the round covers on the timing side of the crankcase halves.
These must be removed at this point. Remove the first round cover. This is for the main bearing and therefore must be tight on re-assembly to preserve crankcase compression. The second cover is for the gearbox main shaft bearing. Note that each of these covers has its own gasket which must be in good condition. The third one covers the drive shaft bearing. This is a double row bearing to enable it to take the enormous strain upon it. IMPORTANT.
Select Top gear before removing primary drive cover and place a tray
underneath the engine to catch oil. Re-new this gasket.

On re-assembly ensure that all teeth on the shaft are to right of quadrant stop, and also that the rear pedal on the outside is fully depressed. The small gear with which the quadrant meshes is held by one circlip. remove the clip with special pliers. Then remove the gear and undue the two upper bolts of the three which were masked by it. This is essential before the crankcase can be split. Invert engine and remove ten allen screws holding the crankcase halves.
There are 4 long, 3 medium, 1 short and 2 very short. Note positions Note also that there is a magnetic drain plug fitted to the gearbox.
Clean it regularly. Re-invert the engine and tap gently to release top section.

Next, remove the crankshaft, it may need prising out but should not need too much effort. Now take out the gearbox drive shaft, note the washer behind the left hand bearing. This is to prevent the shaft moving along. Finally the main shaft can be lifted out. This too has a washer.
If there has been any transmission whine, check teeth of primary drive. Don't forget to replace the strip shown above, this seals the gearbox oil from the crankcase.
On re-assemble turn the gear selector shaft full clockwise (top gear) When you have finished all that work and you re-assemble the engine it should look something like this (above) if it doesn't just do it all again until it does.

QUESTIONS AND ANSWERS
Your Questions Answers copied to paul.stokes2@tesco.net
Over the years, I have often wondered about the significance of the markings found on the drive end of the gear selector drum and the idler gear that drives it from the selector quadrant. They can't be there for no purpose at all. I've asked a fair number of Rumi 'experts' but none has, as yet, provided the answer. I seem to achieve a 50% chance of building and setting up a gear box that jumps out of first gear in operation but operates perfectly on the bench. Now, I don't go along with the commonly held view, "That they are all like that". I can't believe that Rumi produced products for a decade or more, where only 50% of the first gear selections functioned properly. I have come to the conclusion that deciphering those 'man made' markings may be quite important to some of us who have auto-ejection first gears?

Moto Rumi Jumping First Gear. (The factory never sent them out like this)

Recently, at Beaulieu, I engaged a fair number of Rumi owners in conversation about first gear jumping gearboxes and I was staggered how widespread the problem is. Two longstanding Rumi owners provided the most powerful clues to the problem's solution. Not the solution you inderstand but a key to it. Most of the owners past and present, having the problem, inherited it when they bought their machines secondhand. However, these two owners had bought their Rumis new. Both remember breaking kick start return springs and taking their machines to two different dealers for replacement. I'm talking about the late fifties here. From the date of the replacement of springs, their gearboxes jumped out of first gear. I recalled a statement made by a renowned Laverda specialist who once told me that most of the engine damage he encountered in his customer's machines had been caused by dealers and not the owners.
So, as no internal gearbox changes would have been made to effect the replacement of springs, the only likely variance would be in the positioning of the external gear selection mechanism.
The next clue was provided by a casual remark by 'Villiers' friend of mine, "In the factory, that end cover would be loaded top down and not from the side". "but if you do that, the selector quadrant will fall out" says I. Exactly........Why has the quadrant got that expensively and accurately placed hole in it,which you can't see if you assemble it with the side cover?
The answer is, the quadrant is assembled, with the engine on its side, on top of the selector drum with the 'between the teeth mark' on the idler wheel positioned on the most prominent tooth appearing in that little hole. (see drawing above).
Now all this is OK, providing that the other mark on the idler wheel is aligned with the corresponding mark on the end of the selector drum. Simple ain't it?
So without any three handed spider monkeying in holding foot levers in top gear position, you just lower the end cover on to the crankcase making sure you locate the long quadrant shaft into the side cover as you do it. You will probably have to wobble the foot lever a little to engage the selector dogs with the quadrant.
The end of your gear jumping is upon you! This is how it was done in the factory. So far, three gear jumping machines have now benefited from this process.

In the last fifty years or so, none of these assembly markings were understood nor investigated by the dealers or by anyone else that I have been able to find. Various bodges have been perpetrated by them and others to overcome the limitations of the 'select top gear and hold the foot lever in top method. Some are technically quite good, shimming being one but others involved filing elongated slots in the bronze selector drum bearing to gain adjustment to a possibly correct positioning.
It is entirely possible, that gearboxes modified in this way will have to be "blue printed" (returned to original state) back to standard to to benefit from the correct assembly method. So establishing the original non-adjustable setting of the idler gear height is probably important.

Just an aside, I have noticed that quite often the double row ball bearing supporting the output shaft is not butted up against the spacer between it and the gear pinion, this gives too much first gear float, 15 thousands of an inch is more than enough.

I hope that this information helps those of you suffering from the 'inflicted' blues of the Moto Rumi gearbox and that a lot less of you will find yourselves embarrassingly pushing your Rumi up steepish hills, I've been there!!!

Claude CROCHARD