Lambretta GP150/200 Workshop Manual



GP150/200 Workshop Manual

All contents in this section is taken from, Lambretta GP150/GP200, Workshop Manual, Instructions for repair shops, Scooters India Limited, Lucknow (India).

*Please note that we do not recommend that you use all the information printed from the Workshop Manual. There is some information printed in the Manual that we do not agree with. We have added a note next to that information.


Main Features
Maximum Length		1800mm
Maximum width		680mm
Maximum Height		1012mm
Wheelbase		1292mm
Unladen weight		115kg
Total fuel tank capacity		8.10lits
Reserve		0.75lt
Maximum Speed	GP150	85km/h
	GP200	105km/h
Frame		Central beam type in steel tubing
Body		In pressed steel sheet
Front Suspension		Trailing links actuating against two helical springs and shock absorber. Swinging engine unit coupled to shock absorber with coil spring/s
Fuel Consumption	GP150	56 + 6 km/ltr at 40 km/h
(under ideal conditions)	GP200	35 + 5 km/ltr at 40km/h
Engine		Single Cylinder, 2 Stroke, forced air cooled
Bore	GP150	57mm
	GP200	66mm
Stroke		58mm
Capacity	GP150	149cc
	GP200	198cc
Compression Ratio	GP150	7.8 :1
	GP200	7.3 :1
Maximum output at crankshaft	GP150	9.4 bhp at 6300 rpm
	GP200	11.9 bhp at 6200 rpm
Lubrication	Petrol Mixture	Castrol 2T Supreme/Servo 2T kh
		3% during running in
		2% after running in
Starting		By Kick Start Pedal

Gear Ratio		Climbing Ability

Gear	GP150	GP200	GP150	GP200
1st Gear	1:15.35	13.05	36%	40%
2nd Gear	1:9.70	1:9.14	23%	28%
3rd Gear	1:6.72	1:6.20	15%	18%
4th Gear	1:4.82	1:4.81	9%	9%

Carburettor

GP150

MIKCARB

GP200

JETEX-SOI-100

Air Filter

Washable K & N incorporated in air inlet box

Ignition

Flywheel magneto with external H.T. coil and spark plug and Electronic C.D.I Unit

Ignition timing

23° + 1° B.T.D.C (corresponds to 2.90 + 0.23 mm)

Spark Plug

MICO W 5 DC or Modi Champion N4C (Gap 0.5 to 0.6mm)

Clutch

Multi disc type in oil bath

Transmission

Duplex chain drive in oil bath with a damper.

Chain: No. 6.1 Duplex IS:2403/1964; pitch 3/8 in

Gear Box

Four speed constant mesh type in oil bath

Wheels and Brakes

Wheels

Rims

Tyre size

Tyre Pressure

Front

Rear (rider only)

Rear (with pillion)

Brakes

Interchangeable

Pressed steel in two halves

3.50 x 10

1.25 kg/cm²

2.00 kg/cm²

2.25kg/cm²

Internal expansion type with cable control

Electrical Equipment

Flywheel Magneto

6 Pole

At the centre of the handle bar 4 position, clockwise type

Position

0 = Lights out, Ign. out

1 = Lights out, Ign. on, stop light on

2 = City light on, Ign. on, tail light on, stop light on, speedo light on

3 = H/L on tail light on, stop light on, speedo light on

Dipper, Horn and Turn signal switch

On right hand handle bar near the twist grip

Bulbs
Position	Application	No. of	Characteristics	Type	Base
Head Lamp	Dazzle and Anti Dazzle	1	12V-35/35W	Spherical	BA20-d
City Lamp	City Light	1	6V-5W	Festoon	S8.5-9.5
Turn Signal	Direction Indicator	4	6V-5W	Festoon	S8.5-9.5
Tail Lamp	Number Plate and stop light	1	6V-5W	Spherical	BAY 15d
Speedometer	Lighting Speedometer	1	6V 1.5 Watt	Spherical	BA 9S
Pilot Lamp	Turn Signal	1	6V 2W
Indicator Lamps
Pilot Lamps	For headlight beam	1	6V 2W


Horn	12 Volt AC

*Please note that we do not recommend that you use the voltage information in the table above. Although the information is taken from a Scooters India Workshop Manual, we believe that there has been a misprint in the manual. The voltage should read, and we recommend is 12V for all lamps.

Layout of Engine and its Functioning


Electrical Equipment

Electronic Magneto
This magneto consists of pick up coil on stator plate assembly in place of C.B Point and condensor, extended poles on Rotor and C.D.I Unit.
Pick Up Coil
Pick up coil is a transducer which converts angular position of flywheel rotor into electrical pulse. Pick up coil sends a pulse to the gate of S.C.R in C.D.I. unit when it comes in front of extended poles while rotating.
Extended poles on rotor
Extended poles in an electronic system are used to energise the magnetic pick up coil. This happens at a particular angular position on flywheel rotor, so this way it works like the cam of normal system/
C.D.I. Unit (Capacitor/Discharge Ignition Unit)
C.D.I. Unit contains different types of electronic components, like S.C.R (Silicon Controlled Rectifier) P.N. Junction diode and condensor, on receiving signal pulse from pick up coil, SCR starts acting like switch and the condensor which was charged by source coil, discharges into the H.T. Coil.

Timing Setting with Timing Light (Stroboscopic Gun)
The timing once set, will not later in Electronic type Ignition System. If ignition timing is found to be not correct check the CDI unit and magento and replace any faulty part

Checking of Timing Setting with Stroboscopic Gun
a)	Remove the magneto cowl
b)	Connect timing gun
1.	Circuit Diagram of AC Type stroboscopic Gun
2.	Circuit Diagram of DC Type Stroboscopic
c)	Timing is correct if the index mark on the magneto flange aligns the timing mark (arrow on the rotor within 3° at 1200 rpm
d)	If index mark is not aligning with timing mark, remove flywheel rotor and adjust stator plate accordingly, to get correct Ignition timing.

In case there is no index mark either on flywheel or magneto flange, remove cylinder head and assemble the dial gauge with its bracket tool No.57988 for GP150 and 68186 for GP200 at the cylinder top, take the piston at TDC Position. Set the dial at 'O' Rotate the flywheel in anticlock direction slowly. When the dial shows the reading 1.75mm corresponding 18° BTDC, mark the position at flange. A MARK is at the window of flywheel and a white line mark is at pickup coil. Align both he mark at this position. Rotate the flywheel further when he dial shows the reading 2.9mm corresponding 23° BTDC, mark this second position also at flange.

While checking the timing with gun-

The first mark of magneto flange should align with rotar index mark at idling rpm and at the rmp of 3000 and above, the second mark should coincide. If it is not so adjust the stator plate.

Trouble Shooting

It is advised while rectifying the fault of this magnet, Machanic should have service CDI Unit and pick up coil. In the eventuality of spark not coming on spark plug, after checking plug and H.T. Coil, CDI Unit should be checked with the service CDI Unit. If no improvement the Pick up Coil should be checked with service pick up coil. Similarly the same is applicable for the checking of source coil. Service source coil may be used to check and replace faulty source coil.

For pick up one of the possible cause is CDI Unit.

Precaution

Never earth the output of CDI Unit (i.e. violet wire) while engine is running. It may damage CDI Unit.

Jetex Carburettor

Assembly Tolerances and Wear Limits for Cylinder and Piston

(Lambretta GP150)

SI. No.

Grading

Standard

1st Oversize

2nd Oversize

3rd Oversize

Cylinder N Micro Clearance

Piston Max

Cylinder

Piston

Cylinder

Piston

Cylinder

Piston

Cylinder

Piston

B - A

Wear Limit

Max.

Min

+0.018 +0.012 57

+0.062 +0.056 56.9

+0.018 +0.012 57.2

+0.062 +0.056 57.1

+0.018 +0.012 57.4

+0.062 +0.056 57.3

+0.018 +0.012 57.6

+0.062 +0.056 57.5

150

+0.025 +0.019 57

+0.069 +0.063 56.9

+0.025 +0.019 57.2

+0.069 +0.063 57.1

+0.025 +0.019 57.4

+0.69 +0.063 57.3

+0.025 +0.019 57.6

+0.069 +0.063 57.5

150

+0.032 +0.026 57

+0.076 +0.070 56.9

+0.032 +0.026 57.2

+0.076 +0.070 57.1

+0.032 +0.026 57.4

+0.076 +0.070 57.3

+0.032 +0.026 57.6

+0.076 +0.070 57.5

150

+ +

+0.039 +0.033 57

+0.083 +0.077 56.9

+0.039 +0.033 57.2

+0.083 +0.077 57.2

+0.039 +0.033 57.4

+0.085 +0.077 57.3

+0.039 +0.033 57.6

+0.083 +0.077 57.5

150

Assembly Tolerances and Wear Limits for Cylinder and Piston

(Lambretta GP200)

SI. No.	Grading	Standard		1st Oversize		2nd Oversize		3rd Oversize		Cylinder -Piston Clearance B-A in mm Max
SI. No.	Grading	Cylinder	Piston	Cylinder	Piston	Cylinder	Piston	Cylinder	Piston	New Part	Wear Limit
		B mm	A mm	B mm	A mm	B mm	A mm	B mm	A mm	New Part	Wear Limit
1		66.0 +0.013 +0.019	65.9 +0.057 +0.063	66.2 +0.013 +0.019	66.1 +0.057 +0.063	66.4 +0.013 +0.019	66.3 +0.057 +0.063	66.6 +0.013 +0.019	66.5 +0.057 +0.063	0.050 to 0.062	0.200
2	0	66.0 +0.020 +0.026	65.9 +0.064 +0.070	66.2 +0.020 +0.026	66.1 +0.064 +0.070	66.4 +0.020 +0.026	66.3 +0.064 +0.070	66.6 +0.020 +0.026	66.5 +0.064 +0.070	0.050 to 0.062	0.200
3	+	66.0 +0.027 +0.033	65.9 +0.071 +0.077	66.2 +0.027 +0.033	66.1 +0.071 +0.077	66.4 +0.027 +0.033	66.3 +0.071 +0.077	66.6 +0.027 +0.033	66.5 +0.071 +0.077	0.050 to 0.62	0.200
4	+ +	66.0 +0.034 +0.040	65.9 +0.078 +0.084	66.2 +0.034 +0.040	66.1 +0.078 +0.084	66.4 +0.034 +0.040	66.3 +0.078 +0.084	66.6 +0.034 +0.040	66.5 +0.078 +0.084	0.050 to 0.062	0.200

Assembly Tolerances and Wear Limits

Note: The prescribed roughness is obtained as follows:

1.	Bore 0.05 to 0.07 mm undersize.
2.	Fisnish by honing with abrasive nr. 180
3.	Spread a mixture of emery nr.80 and petroleum on the inside surface of Cylinder and keep passing up and down with helical movement a piston of the same nominal diameter as cylinder until piston is moving free-use an old piston without rings. Fit on it a connecting rod as handle.
4.	Wash out very carefully cylinder and ports with pressure water. Immediately after plunge cylinder in petroleum.

Assembly Axial Play and Wear Limits

Between Piston Ring Groove and Rings

(GP150)

SL No.

Piston Groove

Height of Groove 'D' mm

Ring Thickness 'E' mm

'F' Microns at Assy of New Part

Max.

Min.

Max. Limit of 'F' due to Wear Microns

+0.085

+0.065

-0.022

-0.010

107

190

+0.045

+0.065

-0.022

-0.10

180

End Play During Assembly and Wear Limits Between Piston Ring Grooves and Rings

(GP200)

Piston Groove

Groove Height

A in mm

Piston Ring Thickness

B in mm

End Play during assy. of new part
A-B in mm
MAX	MIN

Permissible wear limit

A-B in mm

2.00

+0.085

+0.065

0.107

0.075

2.00

+0.65

+0.45

2.00

-0.01

-0.022

0.087

0.055

0.20

2.00

+0.065

+0.045

0.087

0.055

Assembly Tolerances and Wear Limits

Between Piston and Gudgeon Pin

GP150 & GP200

Piston

A in mm

Gudgeon Pin

B in mm

Permissible wear limit

16.00

+0.003

-0.003

16.00

+0.002

-0.033

0.01

Colour

Code

Gudgeon Pin

in mm

Piston Boss

in mm

White

16.00

+0.002

-0

16.00

+0.003

-0

Black

16.00

-0.001

-0.003

16.00

-0.001

-0.003

Note: The piston and gudgeon pin are marked with a spot of paint for the colour coding. During assembly it is to be ensured that these two parts are correctly matched according to the colour coding.

Assembly Tolerances and Wear Limits Between

Crankshaft and Con.Rod Big End

Width of Crankshaft

Boss in mm

(C)

Width of Con.Rod

Big End in mm

(A)

Roller Cage

width in mm

(B)

+0.1

15.8

-0.05

15.5+0

-0.5

__0.2

15.7

__0.55

Assembly Clearances
(C-A)		(C-B)
Min.	Max.	Min.	Max.
0.25	0.45	0.25	0.75

Wear Limit and Assembly Tolerances for Piston Ring End Gap

Of SI.No.

Type

Nominal (mm) L

GP150

GP200

Piston Ring Gap

'G' Microns at Assy.

Of New Part

MAX. Limit

'G' due to Wear

Microns

Standard

57.0

66.0

200 - 350

600

1st Oversize

57.2