Facom X.730B, Instruction Manual

1. GENERAL INFORMATION

The timing light X.730 B can be used on 2 or 

4 stroke petrol engines with up to 2 sparks 

per revolution. Stroboscopic RPM and ad-

vance measurements are independent from 

the number of cylinders and can be carried 

out by connecting the inductive clamp to the 

spark cable of the No.1 cylinder.

DC or peak voltages can be measured by 

connecting the RED 1 clip to the test point. 

Dwell of each distributors’ camshafts can be 

measured both in degrees or in percentage.

Injection time or duty cycle measurements 

in milliseconds of injectors or other actuators 

can be made by connecting the RED 1 CLIP 

and the inductive clamp to the spark cable 

of the relevant cylinder.

RPM measurements can be carried out 

by the stroboscope, without contact and 

without sticking any refl ecting tapes to the 

rotating part.

2. CHECKS

It is possible to diagnose faults and wears 

without disassembling the part concerned:

1 - in the contact breaker system;

2- in the centrifugal advance mechanism;

3 - in the timing system;

4 - in the vacuum advance system;

5 - in the vacuum retard system;

6 - in the battery and charging system.

A check and a correct adjusting of the diffe-

rent parts described above allow to optimize 

the engine performance, reduce wears, fuel 

consumption and harmful gas emissions.

3. PRECAUTIONS

In order to prolong the lifetime of the unit, 

it is necessary to softly coil the cables but 

never wrap them around the timing light.

4. OPERATING INSTRUCTIONS

• Connect the timing light as shown in Fig. 

1.A reversed connection to battery of the 

RED/BLACK clips does not cause damages 

to the timing light.

Mount the clamp at about 10 cm from the 

distributor, with the arrow pointing towards 

the spark plug.

Make sure the cables are far from exhaust 

pipes, rotating parts and high voltage leads.

• Check that the coil’s electrical connections 

are correct. Reversed connections can cause 

reading unsteadiness and decrease the 

engine performance.

• Check that the timing marks can be seen 

clearly; bring otherwise the piston of the 

No.1 cylinder at TDC in compression stroke, 

and trace with a white chalk two signs in line 

on the crankcase and the crankshaft pulley.

• By pressing the D key, the strobe light 

should fl ash regularly; an irregular fl ashing 

could be caused by :

- non-resistive spark cables;

- discharges between cap poles or to ground 

due to dirt or moisture;

- leakage to ground or between cables due 

to ageing or cracks in the insulating sheath;

- wear or excessive gap between rotor arm 

and poles or cap’s central contact;

- too small spark gap or spark electrodes 

with too much carbon residues;

- too low voltage on the spark plug due to 

faults in the ignition system;

- timing light too near to spark cables, 

distributor or ignition coil.

• Check against the light that the clamp’s 

cores match completely. With a cloth, 

remove possible grease and dust.

5. CHECKING THE DWELL ANGLE

• Start the engine and make it warm till 

reaching a regular rotation at idle.

• Disconnect the vacuum tube, if specifi ed 

in the data manual.

• In breaker points or transistorized ignition 

systems, the Dwell angle is checked by 

connecting the RED 1 clip to coil negative.

• In some transistorized systems, a zero 

reading means an interrupted reluctor or 

wiring. If the reading is very different from 

3÷5 ms, the causes can be: a wrong distance 

between poles and reluctor, a faulty module 

or a resistance of the ground connection 

higher than 0.1 Ohm.

Check the ECU, in case it should directly 

drive the ignition coil.

• In case of breaker points systems follow 

the instructions page 7 to check that the 

measurement in degrees or percentage 

corresponds to the manufacturer’s data. 

Readings out of tolerance can be due to: 

wrong distance between contacts, damages 

to the base plate or the contacts, worn 

camshaft and distributor shaft .

• Bring the engine to 2000 RPM, variation 

should not be more than 3 degrees (some 

distributors have higher variations, it is 

therefore necessary to check the features 

declared by the manufacturer before 

changing it).

Higher variations can be due to the same 

causes described in the previous chapter, 

loose contacts, used contacts’ pivot.

In case of an excessive variation when 

connecting the vacuum tube, the pivot post 

of the base plate could be damaged.

TECHNICAL FEATURES

READING    

SCALE 

RESOLUTION

– RPM  

400÷19.999 rpm  

1 rpm

– Stroboscopic advance  

0÷78°/90° (400/465 rpm)  

0.1°

– DWELL (for each cylinder)  

0÷ 65 ms  

0.1 ms

 0÷100% 

 0.1%

0÷120° (> 600 rpm)  

0.1°

– DC Voltage  

1÷70 Volts  

0.1 Volt

– Peak Voltage  

1÷70 Volts  

0.1 Volt

– Stroboscopic RPM counter  

60÷6000 rpm  

1 rpm

– Memory of readings  

6 s (from key D release)

– Power supply  

9.5÷15 Volts (9.5÷35 V optional)

EN

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