History of Rumi
Links to subjects
Chain & Sprockets
Forks & Steering
Front wheel and brakes
Rear wheel and brakes
Cylinders and cylinder heads
Kick Start mechanism
Extended bush mod
Chains & Sprockets
Forks & Steering
The steering ball cups have 26 X 4.75 mm ball bearing in the upper and lower cups totalling 52 balls.
. The Rumi Scooter frame is made up of just two parts
- The rear Section
- The front section
All of the Rumi Frame parts and mudguard are made
from cast alluminium. The frame can be polished to a
bright chrome like finish or can be easily painted
Recommended hub bearings size: 15 X 35 X 11 (2off)
For relining your brakes contact SAFTEK Tel: 01274 862666 / Fax: 01274 862444
Recommended Hub bearings size: 20 x 47 x 14 (2 off)
Bearings shown in "rear suspension"
Rumi ignition is a relatively simple system with two contact breakers to be found inside the flywheel.The contacts should be set at 0.012" (inch) or 0.30 mm.The "O" scribe on the flywheel is where the contact should be fully open at T.D.C
The "A" scribe on the flywheel is where the contact should just start to open before T.D.C. The standard system is 6 volt A/C magneto. There are two coils within the flywheel
a lighting coil and an ignition coil. The spark plug gaps should be set to 20 to 22 thou or 0.5 mm. Two HT coils can be found in the front light Nazelle.
Rumi owners are more inclined to upgrade the system to an electronic 12 Volt systems that are now commonly available.
ADJUSTMENT OF THE TIMING
To adjust the timing on the Rumi the removal of the flywheel is required.
This is done by loosening the centre nut with a special castleated tool and a special puller. A Lambretta puller should do the job. Remove the centre nut.
Now use the puller by first screwing it into the flywheel centre. Now screw in the centre bolt on the puller until the flywheel is free. Remove the flywheel.
You will now see the back plate with 3 screws holding it tight to the crankcase. Loosen the 3 screws. Now it will be possible to adjust the timing and the contact gaps. To advance the timing, rotate the back plate clockwise. To retard the timing rotate the back plate anti-clockwise.
Don't forget to re-tighten the 3 screws when completed.
The Rumi gearbox is 4 speed for post 1956 and 3 speed pre 1956
Early motorcycle Sports and Squirrels also had 3 speed gearboxes.
The gearbox is operated by a foot change, toe and heal pedal
one down and three up.
There are 4 ball bearings in the gearbox. Item 20 x 3 Type 6203 C3 or C4
Item 31 (output bearing) Type 3203 B double row ball bearing.
Seals: Crankshaft side Magneto: Size: 17 x 35 x 7
Output shaft: Size 25 x 35 x 8
The clutch on the Rumi runs in oil and is known as a wet clutch.
The clutch consists of 3 cork plates and 3 metal plates
Straight classic SAE 30 or equivalent oil must be used in the gearbox
to prevent clutch slippage. Additives in modern oils are absorbed in the
clutch plates causing decreased friction thus causing slippage.
Lights on the Rumi are powered by the 6 Volt Magneto lighting coil.
Early versions of the Scooter had a swiveling headlight to enable
the rider to have a better view of the road when cornering.
Later models had a fixed headlight.
The rear light is by a 6 Volt Festoon bulb.
The lighting switch is placed on the handlebars.
Brake lights were not fitted as standard when manufactured, however
it is now a legal requirement of British roads.
A 12 volt system conversion is now readily available.
Crank shaft bearing Outer: 6303c3 or c4
Inner: 6204c3 or c4
Crankshaft seals: Outer crankshaft and side plate: 17 X 35 X 7 3 off
Centre crankshaft seals: 25 X 42 X 10 2 off
Crankshaft needle roller size: Length 9.80mm. Diameter: 3mm with rounded ends.
Rumi Made two types of cylinders for the scooter models.
The Formichino always had cast iron cylinders while the Tipo Sport
originally had chrome plated aluminium cylinders. Later models of the Tipo Sport
reverted to cast iron. The Tipo Sport had larger inlet and exhaust porting
to allow for extra power. The Tipo Sport also had higher compression heads than the Formichino.
There are two types of pistons used on the Rumi.
A three ringed piston for the Formichino and a two ringed piston for the Sport
It is believed the Sports chrome bores convinced Rumi to go for the two ringed
version due to a third ring catching the chrome at the edge of the ports.
It is also believed Rumi decided on the two ringed version to reduce friction. The piston crown has an unusual "V" deflector which is easily identifiable as Rumi. The pistons are fitted to the conrods as shown on the left hand picture, The "V"
points up. /\
The Rumi kick-start is by a simple quadrant and ratchet system.
One of the failures of the system is mechanical wear on the ratchet teeth and ratchet bronze
bush. The ratchet wear is not easily overcome but grinding back the angles on the
ratchet to allow better grab works well. A simple mod to the bush also helps
enormously. The old bush is removed and a new longer bush is fitted to support
the ratchet gears better. (Eliminates rocking of the gears)
The gear change mechanism suffers from a similar fate as the kick start gears.
Over time the ratchet teeth on the quadrant wear causing a lesser movement
of the selector drum thus causing poor engagement of gears, especially 1st gear.
It is worth checking wear on the quadrant before dismantling the engine to overcome gear selection problems.
The output sprocket on the Rumi scooter is decided by
the size of the wheels.
A 14 tooth sprocket is used with 8" wheels
A 13 tooth sprocket is used with 10" wheels
The final drive sprocket remains the same ( Rear wheel)
The chain is a 1/2" x 3/16" or metric 415 with 98 links.
The renolds number is 110044 with 8.51 dia rollers
The chain and sprockets are incased within the
aluminium swing arm (See Rear Suspension)
Rear suspension is by a swinging arm which is damped by a four segment
rubber donut device.
The swinging arm has a chain adjuster across the main shaft. (Item 10, 13 &15)
By rotating the shaft the cam adjusts the tension of the chain.
Suspension is by leading link with springs. The Rumi front suspension
has very little damping. Damping is achieved by tightening and locking
the two nuts on the link arm pin (Item 25 & 27) 16 mm pins.
large nut x 4 = M16 x 1mm fine thread half nut.
Small nut x 2 = M12 x 1mm fine thread half nut
There are 52 ball bearings in the steering column, 26 in the upper
and 26 in the lower.
Item 11: Rubber pads: 10mm depth x 27mm long X 20mm wide
Toggle down for Frame, Wheels and Brakes, Ignition, Spark plugs, Gearbox, Clutch, Lights, Crankshaft, Pistons, Kick start, Gearchange mechanism, Chains/Sprockets, Forks and steering.