May 2013 1965 Lambretta TV 175 series 3

May 2013 1965 Lambretta TV 175 series 3


Now that the front end of the wiring is done, time to finish the back end.

This includes the electronic ignition stator (fitted in an earlier post), regulator, CDI, Earth (ground) wiring and spark plug.

This bike was originally all AC (no battery tray welded to the frame) and it will remain that way. It also did not have a regulator, only a small junction box. Ive chosen to install a regulator to smooth out the voltage spikes coming off the stator. This helps to not blow light bulbs and leaves me the option to charge any accessories (phone, GPS, etc) in the future if I so desire.

The plan is to make this bike look somewhat original with modern upgrades. So I obtained an original regulator housing from a model that would have had one.

Modified the inside in order to hide a small BGM regulator within it. Here is a pic with the cover off before the wiring was completed. I made a crude but functional mounting bracket. Also snaked a ground wire from the regulator through one of the original mounting holes.

Mounted it to the rear frame strut. Here is a pic of the ground wire from the regulator and the braided cord Earth strap that goes between the frame, engine and components. Scratched away some paint to get a good ground contact between the frame and this mounting bolt.

Cover fits nicely and is held on by a wing nut. New rubber top to keep the wires from the loom and stator in place.

Over on the other side, I have fitted a modern CDI (capacitor discharge ignition) unit. This replaces the original ignition coil that a points based stator would have used. Both use the same principle to store power from the stator in order to supply the spark plug with quick bursts of voltage to create the spark at the right time (once I set the timing correctly).

BGM had been making modern CDI units housed in a tube form to look like the old HT coil unit but they are not available at this time. If it becomes available again, it would round out my hidden electronics theme.

But for now I have this one that will work well. Picked up adaptor plate from Peter to mount it to the holes in the frame that were originally for the ignition coil. Found an old ball rubber cap in my bin of random Vespa parts that Ive used to cover the the four connections from the stator and wiring loom.

The braided wire earth strap can be seen there as well, connecting to the ground wire from the CDI unit. Back on the other side of the frame, I decided to sneak an extra bit of wire through the frame tube to connect the grounds from this to the tail light mounting bolt.

This ground connection normally utilizes the frame itself and probably would be fine as is but this is an extra bit of insurance. Ive seen that Mark across the pond at MB Developments has started making longer earth straps with four connections for this same idea.

And finally to complete this entire wiring scheme, there is now the HT cable from the CDI to the spark plug. You can see it routed here. Over the river and through the woods. Over the rear shock, through the rubber grommet on the rear frame strut, through the rubber buffer on the frame and finally to the spark plug cap. Added a little rubber cone to the CDI end of it as well.

The end is near! A few misc tasks left, install the rear floor boards, flywheel and set the ignition timing.

Posted in Wiring

Headset and headlight

Everyday a little closer to the finish line. Today I wired up the headset internals and closed it up.

First, set the headset cover in place and installed a new 12v bulb in the speedometer. This bulb holder has been grounded to the frame. Then attached the speedo cable to the speedometer.

The original headlight lens, glass and brown Bakelite plastic headlight bulb holder/wiring junction block were all in excellent condition. Cleaned everything up a bit and reused them.

This junction block attaches to the headlight housing and is what connects the handle bar switch, horn, speedo bulb, ignition key switch, and headlight wiring to the main wiring loom.

May 2013 1965 Lambretta TV 175 series 3

The simplified Casa Lambretta loom made it very easy to wire it all up. The wiring diagram in the Stickys manual was also a big help.

It also acts as a bulb holder for the main headlight and festoon type running light. Here you can see the bulbs installed. New 12v bulbs since the stator will be producing 12 volts instead of the old 6v. The headlight bulb is a halogen type.

Then attach the headlight lens to the junction block. It is secured by a metal clip and spring. Ive never heard of this being an issue but I wrapped the top spring clip in electrical tape so that it did not interfere with the wiring and bridge the two connectors it is resting upon.

On the throttle side the headset cover is secured by a new stainless steel bolt and star washer. On the gear selector side, I have fitted a mirror bracket which replaces the stock bolt. This can be seen in pics further down.

Although the original headlight housing and glass were in excellent condition, the metal headlight ring had deep gashes in it. I opted to replace it with a new Casa Lambretta polished metal ring. It is installed with four new stainless screws.

At the bottom of the ring, there is a fifth screw that is attached to a special nut that allows the headlight to be focused up and down. This speciality hardware was in good usable condition. Im glad I had kept it bagged and tagged with the headlight housing.

Here is the completed assembly. The mirror will need to be adjusted and I still need to install the rubber handlebar grips but Im very excited that this task is done. Her light will be shining bright soon.

Now that this end of the wiring loom has been checked off, Ill be focusing on completing the wiring at the other end.

Fourth hand tool

Quick update, tightened the clutch and gear cables with the help of the trusty fourth hand tool and Stephen Hellcat holding the gear shifter in the neutral position.

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