650, 750 GT, 750 SF1, SF2, SF3
B8EV ou EGV
0,6 to 0,7 mm
750 S, 750 SF, SF0
B9 to B10ES
B9 to B10 EV ou EGV
0,6 to 0,7 mm
All 3 cylinders
B8EV ou EGV
Denso IW 27
0,6 to 0,7 mm
Points and condensers (650 and 750 Laverda):
0,4 to 0,5 mm
750 SFC Electronica ignition module
original Bosch ignition fitted on the SFC Electronica was special for this model.
When these modules came later out of stock,
the factory decided to use the same # 034 ignition box as fitted on the late 1000cc 180° (with Nippo Denso alternator), Jota 120
and RGSs. This new module has exactly the same performances than the older one, however the timing is different, meaning that
the woodruff key (of the rotor) has to be removed.
The factory advised to machine in the rotor a new groove for the woodruff key, however most of the time the key was simply
removed and the rotor was timed only by tightening its nut, secured by a toothted washer.
See technical sheet #16
Ignitions 1000/1200 LAVERDA:
* BOSCH HKZ (1973 - 1978):
The original Bosch ignition of the 1000 Laverda is a source
of various problems, above all the first serie HKZ. If you have not yet
replaced it by a good system like the IIS (see page "improving"), here are the main points to check on a Bosch HKZ system.
However keep in mind that this ignition is the first thing to change on a 1000 Laverda... See the "improving" page
- Checking the original Bosch HKZ ignition (1000)
Check the ignition coils: Disconnect the black wire (bikes before the end of 1973)
or the red wire (bikes after 1973) from the
junction box under the tank. Connect an ohmmeter tothis wire and to earth. Resistance should be of 250 to 400 ohms. If not,
change the coil.
Check the pick-ups: For bikes before the end of 1973, disconnect one of the violet
wires from the junction box under the tank.
Connect an ohmmeter to this wire and to earth. Resistance should be less of 100 ohms. Check the other violet wire. If resistance
is higher than 100 ohms, change the stator. For bikes after 1973, disconnect the two wires coming from each pick-up. Connect an
ohmmeter to these wires. Resistance should be less than 100 ohms. If not, change the stator.
- Checking the original charging system (1000)
Disconnect the yellow/black and the yellow wires from the junction box under the
tank (two yellow/black wires for bikes before the
end of 1973). Connect an ohmeter, resistance should be very low. If there is no resistance or, at the contrary, a very high resistance,
change both charging and lighting coils.
- Checking the Bosch rectifier
Disconnect the two red wires and the earth wire on the rectifier. Connect an ohmmeter
(+ and -) successively to the two positive
and to the negative, resistance should be very low. Reversing the ohmmeter connections, resistance should be infinite. If not, replace
- If ignition problems
Ignition switch on "ON"? If
2- Check ignition coils. If OK:
3- Check pick-ups. If OK:
4- Check stop engine relay.
* BOSCH BTZ (1978 ->):
BTZ has a better reliability, even if the ignition HT current voltage is still
unsufficient. One again, replace it ASAP by a modern
ignition, IIS or DMC2 (see the "improving" page)
starting problems, often followed by a detonation into the exhausts often mean
a failure of the ballast resistors. A good way
to solve the problem is to shunt the resistors. In this case, the module looses its protection against the HT current, but I know several
bikes which run ok without these resistors. Your own choice though...
Another common problem is that the ignition modules are not perfectly grounded. Check the connexion and, if necessary, connect the
earth wires directly to the battery negative.
- Checking starter motor (1000)
|Brush pressure|| |
750 à 1600 gr.
Minimum lenght of brush
35 à 55
9000 à 11000
340 à 430
How to replace Nippon Denso High Tension ( HT ) connector wires:
Nippon Denso Ignition Coil High tension lead replacement ( Pinky, beige colour ) stamped 028700.
There is an epoxy resin around the HT cable entry point on the body of the ND coil which can be carefully removed by use of small side
cutters. Take care not to damage the ignition coil body plastic case.
There are two parts to the HT lead, the inner HT lead/copper wire with insulation cover and an outside thin plastic sleeve or sheath.
Pull hard on the HT lead until it comes out of the coil body tube, this will leave the outer sheath still inside the coil tube. By carefully
pushing a screw driver down between the sleeve and inner bore of the tube until you feel the remaining epoxy break its bond, continue
working around the sleeve until it frees from the bore. There is a standard spike termination at the end of the bore, be careful not to
A good quality copper core HT lead of 7m/m diameter ( 8 m/m will not fit in the bore ) can then be inserted into the bore ( tube) until is
stops and then a good quality silicon sealent or Epoxy can be used to secure the new HT lead to the ignition coil body, try not to use
building grade silicon as it cures by liberation of acetic acid which attacks copper components. Use 738RTV if you can find it at the local
electrical wholsalers, or at least neutral cure silicon which is becoming more available from hardware stores.
Once done use NGK spark plug covers with 5.0K ohm supression resistance to terminate the HT leads for clean firing of the spark plugs.
- How to find Nippon Denso HT coils for Bosch BTZ?:
problem to find them new or used (brokers), the twin coil was fitted to any Suzuki
4 cylinders of the Eighties and the single one was
fitted to Suzuki 380, 550 GT and others
2 strokes of that time.