Granturismo RS ignition conversion

3. Pre-fitting preparation

This ignition is a performance part and is specifically aimed at the technical and electrical performance available to Lambretta users. It is important to remember several key things about this ignition and manual before proceeding.

1. The ignition requires modification to the mag flange
2. The ignition is ONLY for GP crank tapers
3. The ignition is a generator type NOT flywheel magneto, consequently a battery is required
4. This manual describes and illustrates the use of Aprilia RS125 rev counter and ancillaries

Kit contains the following parts:

1pcs Steel pointer
1pcs CNC alloy fan (air cooled only)
1pcs CNC alloy stator plate
3pcs SS counter sunk fan screws (air cooled only)
3pcs SS socket head stator screws
1pcs Spacer washer (optional OTS)
1pcs Custom loom (optional OTS)
1pcs Machined rotor (optional OTS)
1pcs Machined mag housing (optional OTS)

In addition to the kit you will need:

1. Donor Aprilia RS125 flywheel (122 type) 98-2006
2. Donor Aprilia RS125 windings (122 type) 98-2006
3. Donor Aprilia RS125 pick-up (122 type) 98-2006
4. Donor Aprilia RS125 wiring loom (122 type) 98-2006
5. Donor Aprilia RS125 rectifier (122 type) 98-2006
6. Donor Aprilia RS125 CDI de-restricted (122 type) 98-2006. Information on derestricting OEM CDI here:
7. Donor Aprilia RS125 clocks (122 type) optional 98-2006
8. Donor Aprilia RS125 coil (122 type) 98-2006
9. Donor Aprilia RS125 rave unit (122 type) optional 98-2006
10. A good quality Lambretta key ignition switch Lambro, 5 wire, 5 position)
11. Good tools, soft locking compound

The (de-restricted CDI) OEM RS125 ignition has a large amount of advance, too much for Lambretta applications. This is due to a number of factors the vast majority of which cannot be duplicated in Lambretta engines. For this reason the mid-point  position of the pick up on the stator corresponds to a retarding of the OEM timing by 4 degrees. You will notice that the stator allows for adjustment both in advance and retard, this allows for +/- 4 degrees of adjustment.

From the graph below you can see the advance and retard characteristic and the pick-up minimum and maximum positions that are attainable from this stator (max advance is equivalent to stock RS125). Programmable ignition curves can be achieved by using either HPI or Zeiltronic CDI units.

Note: Stock CDI’s have an emission dip; this will hamper operation in a Lambretta. CDI’s are best de-restricted for this build, most on Ebay are, instructions on how to de-restrict CDI’s can be found at point 6 above if required.

Granturismo RS ignition conversion

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