Wiring diagram for 1980 triumph t140v ignition

NGK Part # 5044 {#1262, 4525, 6824, 7051, B8EV, B8EVX, BR8EIX, BR8EVX} Iridium; Iridium IX
750 Model; T140V; Gap .024 CHAMPION Part # 88091 More Info {#8809, 88092}
.036 Good luck, Bill

Just to make sure we're on the same page, I'll assume you mean one of these:

http://www.ebay.com/itm/Working-Lucas-Rectifier-Triumph-Norton-BSA-500-650-750-Bonneville-Lightning-93r-/310849859745?pt=Motorcycles_Parts_Accessories&hash=item48601870a1&vxp=mtr

If so, let's go to this pic:

http://i1167.photobucket.com/albums/q637/danimal991/rectifier3.jpg

(click pic to enlarge a little)

IF you have the terminal marked #1 (not all do), this is an additional ground, to supplement the ground from the mounting bolt (#5).
Numbers 2 & 4 are where the alternator leads plug in. Doesn't matter which, as the voltage from the alternator to the rectifier is AC current.
Number 3 (center terminal) is the "hot" lead (converted to DC voltage), and splits off in two leads, one going to the system, the other going to the Zener Diode, which acts as the voltage regulator.

Now, a few things to be aware of:

When removing or installing the rectifier, ALWAYS use a wrench to hold the "bolt head" (under terminal #1 in the illustration) to keep it from turning while you loosen/tighten the nut.
If you don't do this the "plates" will turn, breaking their internal connection(s).
In that case, you might as well take it off and throw it in the trash, and go buy another one!
Make sure the mounting is contacting clean, bare metal (no paint, rust, etc).
I usually use a piece of Scotch Brite and shine up the mounting area, put a dab of dielectric grease (available at auto parts store) and slip an external tooth lock washer over the bolt threads before inserting it into the hole and tightening with the nut:

http://1.bp.blogspot.com/-HGJnod9WkGE/UXA77e-kxSI/AAAAAAAAAGQ/drj3iZ3eCB8/s1600/External+Tooth+Lock+Washer.jpg

The teeth of the lockwasher dig into the mounting surfaces, giving a better electrical connection.

does this vehicle still have the old lucas points or has it been modified to electronic ignition ,also is the vent cap clear in the fuel cap

It has been a while... but I believe there is a round access cover about 2" in diameter on the right hand side of the bike, forward part of the engine.

That corresponds with the end of the exhaust camshaft.
In this photo, it is chrome plated. They are held on by two philips head machine screws.

The points themselves are mounted on two plates. The first plate adjusts both sets of points, the second adjusts the difference in the two sparks.



That said, you might be on a wild goose chase. Most of the older T120s and T140s have already been converted to Boyer electronic ignition systems. MUCH more reliable, and much less maintenance. Smoother, and more precise as well.

Boyer conversion or not, the access plate in in the same place. It just might be a "pointless" ignition.

See these guys - they have very good telephone support - and will have Boyer kits in stock.

British Cycle Supply, item 331 Series Boyer Electronic Ignitions

The points cover should be on the right hand side of the engine, at the end of the exhaust cam shaft.



It is possible that the original plate was replaced by an aftermarket version with cooling fins. That doesn't do much, but it *looks* cooler to some eyes.

Most of these bikes have been refitted with Boyer ignition kits, so under the plate the points are no longer there. They are likely replaced with a sensor and magnetic sensor. That is a MUCH more reliable and maintenance free system.

If you do still have points, there will be two contact sets. The entire disk shaped plate will rotate to adjust timing and a smaller partial plate containing the second set of points can also be adjusted. That gives you control over timing, and difference between cylinders.

Really, I was a stickler for "original" on my bike, and I regret not changing to an electronic Boyer system as soon as they became available. Go for the upgrade. It's well worth it. A good shop can have it done in an afternoon, and you will never have to think twice about ignition or timing again.

Boyer Electronic Ignitions
http://www.britcycle.com/products/331/331_series.htm

drop the needles 1 position maybe two if you changed jets go smaller if you changed nothing slides could be warn.

OBVIOUSLY THE BIKE IS RUNNING HOT THE FIRST THING TO TRY IS HOTTER PLUGS BLACKENING IS CAUSED BY EITHER RUNNING RICH THROUGH ELECTRICAL PROBLEMS WRONG PLUG HEAT RATING SO IF DIFFERENT PLUGS DONT WORK ITS GOING TO BE ELECTRICAL MISSFIRE THEN YOU NEED TO BE LOOKING AT HOW YOUVE WIRED THE PARTS THAT YOU HAVE ADDED

most of the wires wont be connected just the basic's pos/neg ect. if its going into an older model