Repin Connector

[Duck749]

I hope I am posting to the correct forum section, I read this was good for T150/T160 models.

I am working on cleaning some of the old harness and removing years old electrical tape. My game plan is to remove pins from connector so I can put new heat wrap on and make a visually cleaner harness on some sections.

My question is how do I release the wire/pin from the connector? Some other bikes I am use to a single metal tab you press in and pull wire apart. This looks to have a tri-pin connector with three tabs?

 

[grandpaul]

I sure don't know. I would just use a decent quality electronics spray cleaner.

 

[Duck749]

All set now, found some pics of pin connector online. Switching from dental pic to safety pin was enough to press tab in and release wire from connector.

 

[Rudie]

how do I release the wire/pin from the connector?

I first came across these connectors (known as "AMP connectors" after the maker) on my brand new T160. They are horrible connectors, gave problems even on new bikes; on my T160, the White/Yellow wire connection from the kill switch to the coils failed within two years. When I rewired the bike (at five years old ), I cut off the connectors, made new connections using standard 3/16" o.d. bullets and snap connectors. Still have the bike, the connections I made have never given any trouble.

Standard 3/16" o.d. bullets and snap connectors are available in the US available from British Wiring - bullet, snap connector. British Wiring also have the tool for pressing bullets into snap connectors, usually have the bullet crimping tool but not on their website at present (email or phone?).

make a visually cleaner harness

An electrically cleaner harness would be better?

Not much tape on the main harness inside the headlamp shell has to be stripped back before you will find small short wires between some AMP connectors pins and standard snap connectors wrapped inside the harness tape.

Not only was this unbelievably poor electrical practice by the original Lucas company designers (apparently just to accommodate the awful AMP connectors?), if you are working with any Lucas or pattern harness more than about ten years old, any snap connector should be replaced for reliability.

cleaning some of the old harness and removing years old electrical tape. My game plan is to remove pins from connector so I can put new heat wrap on

Ime, these particular connectors, that is a good definition of the phrase "polishing a tu*d". Since my first rewire, I have helped a number of people with electrical problems caused by the connectors. I would not ever work to save them.

Assuming a T160, other changes for "an electrically cleaner harness":-

. If there are thin Red wires from the harness connected to the battery positive terminal, there should not be, they should have been disconnected and insulated securely as a result of a NVT Service Bulletin in May 1975 ...

The problem is a standard harness also has thin Red wires connected to the engine; if the thick cable is not connected to the battery positive terminal and the starter button is pressed, the starter circuit will try to complete back to battery positive through the thin Red wires ... with predictable if one-off results. Otoh, if nothing except the thick cable is connected to the battery positive terminal, all electrical circuits on the bike can complete through that cable, if it isn't connected, nothing electrical will work.

. Depending when the bike was made, earlier bikes can have under-specified thick cables.

Early bikes had cables made from 37 strands just 0.7 mm o.d. (actually #22 (British) Standard Wire Gauge), rated for 110 Amps; however, in practice, the standard starter could draw considerably more. I know of bikes with 37 x 20SWG (~0.9 mm o.d.) cables (rated for 170A) but I do not know how the change came about - official on later bikes or by dealers or owners after NVT closed.

Either 37-strand cable is very stiff, I have always replaced with 196/0.40 (196 strands each 0.4 mm o.d., also rated for 170A); the cable o.d. is 3/8" over the insulation, only slightly bigger than the original's 5/16" o.d. If this cable is not available in the US, its total conductor cross-section is 1 square inch.

. The Brown/Blue wire between battery negative and ignition switch, originally via rectifier and Zener diode was under-specified even for the original alternator - alternator rated for 10.5A @ 5,000 rpm, wire rated for 7.5A, alternator output exceeds wire rating above about 3,000 rpm ...

Thanks I think to Lucas's safety margin in the wire rating, standard T160 electrics just about manage to function. However, the standard alternator is not up to keeping the battery charged during prolonged low rpm running, especially for electric-starting and particularly if also the lights are on.

I fit a thicker (higher-rated) Brown/Blue wire (available in the US) as a matter of course during rewires, becomes a necessity if the alternator is replaced with one with greater output. Owner wishing to keep the standard harness, I thread the new thicker wire alongside the harness and secure it with cable ties. If coloured wire outside harness does not fit with your "visually cleaner harness" desire, thread the wire through black PVC sleeving (3 mm or 4 mm) before securing it?

 

[ManInTheJar]

Some non-conductive electrical grease applied to the connector pins and the connector ends can help make them more reliable.

 

[Rudie]

Some non-conductive electrical grease applied to the connector pins and the connector ends can help make them more reliable.

Ime, the main problem with "AMP connectors" is individual pins and sockets do not make good contact with each other. Not sure how adding non-conductive grease would make them more reliable?

 

[Duck749]

Great insight, appreciate the feedback!

Looks as if the bike is setup for positive ground, is it recommended to switch it over to negative ground while also ensuring proper wiring is used? More or less asking if the positive ground is still robust enough if going through the hassle of updating wiring.

I have found some connections are frayed and or lose in the connectors, also have wires not connected to anything. The PO took the starter out, assume didn't have battery and was using kickstart only. Hence in my schematic note in other topic asking for detailed electrical drawings so I can chase wiring around.

 

[Rudie]

Looks as if the bike is setup for positive ground, is it recommended to switch it over to negative ground

Ime, only reason to swap to "negative ground" is if you have other vehicles with it and you cannot deal with the concept of two different "grounds". In reality, "ground" does not make any difference to how DC works, and Lucas put insulated wires in harnesses both between battery negative and components and between components and battery positive.

Also, the British/Lucas colour code for "negative ground" wires is Black, Red wires indicate "positive ground".

some connections are frayed and or lose in the connectors,

In the US, British Wiring sells all the standard connectors and insulators; unfortunately, certainly their website is patchy with stock of the correct crimping tools; maybe worth an email or phone call to check availability?

have wires not connected to anything. The PO took the starter out, assume didn't have battery and was using kickstart only.

Even if the starter had been removed, I would be surprised if the bike did not have a battery?

However, no starter, ignore the parts of my previous post on thick cables and disconnecting thin Red wires from the battery positive terminal ...

A modification I make to all "positive ground" British bikes without electric starters is to move the main fuse to a single Red wire connected to the battery positive terminal itself; if the harness has multiple Red wires connected to the battery positive terminal, I cut these off the harness battery terminal, fit a bullet terminal to each wire end, connect them to the fused Red wire with a snap connector.

The reason is "positive ground" means the metal parts of the bike are connected to the battery positive terminal. If you are unlucky, something metal accidentally touches the battery negative terminal itself and another part of the bike, the standard fuse in the Brown/Blue wire will not blow because the short circuit is not through it ... ... instead, the Red wires' will start to melt ... Otoh, any fuse in the single Red wire connected to the battery positive terminal itself will blow.

For the same reason, any "negative ground" bike without electric start, I put the main fuse in a single wire connected to the battery negative terminal itself, connect all other "ground" wires on the other side of the fuse.

have wires not connected to anything. The PO took the starter out,

The starter wiring is:-

. In the right-hand handlebar switches, a White/Red wire from one of the buttons went to one terminal of a relay bolted under the battery tray.

. The White/Red wire is supplied by a White wire. If planning to disconnect the latter, check it does not also supply either the kill switch lever (its White/Yellow wire supplies the coils (if switched by points) or aftermarket electronic ignition if fitted) or the front brake switch (Brown wire).

. At the starter relay:-

.. In addition to the White/Red wire from the handlebar button, depending on when the bike was built, there could be either another White/Red wire or a Purple/White wire. Early bikes had the two White/Red wires and, although one was obviously thicker than the other, I suspect too many were connected to relay terminals incorrectly, the starter did not work so NVT had Lucas change the thicker White/Red for Purple/White.

.. Also a Red wire, a White/Blue wire and a Brown/Blue wire. This Brown/Blue is completely separate from the Brown/Blue between battery negative, rectifier, Zener diode and ignition switch, was connected to a male spade terminal on the same starter solenoid terminal as the starter cable from battery negative.