TCI forensics NO WONDER!!! they are problems!!!

[XSLeo]

Capt Zoom, I have no idea what ignition Triumph uses, but the XS650 never in all the years produced did it ever have a CDI. Points or a TCI is what it has.
Leo

 

[mouser]

Well after re-soldering only the main connections this one works again....as to rebuilding them...with a new board...break even would be about 50 units... Try re soldering..It worked for me...

 

[gggGary]

To make it modern it should have a TPS input? I have wondered several times if one of the aftermarket programmable Harley ignitions would work?

 

[pamcopete]

Mac...,
The Triumph Scrambler is a 270 engine the Bonneville is a 360.

 

[MacMcMacmac]

So it is. My apologies. That's what happens when you make assumptions. You look like an ass, and the ump will shun you.

 

[Capt_Zoom]

Sorry...my apoligies. Mixed up TCI and CDI because this is what i was thinking might work (probably not though).
http://www.british-customs.com/programmable-hi_performance-cdi-box.html

I just don't know if something like this would be programmable that far away from the triumph's stock settings as the xs650 might be.

 

[1974jh5]

After much thought I think this is auto advance ignition was a bad idea! I think they would have been further ahead to set it up for a fully advanced ignition with a circuit and a "button" to retard the spark for cold starts.... I'm thinking back to the day when Harleys and Indians and many more...had a mechanical way of retarding the ignition for starting. The only time it was necessary to retard the spark was for the first cold start of the day....or they would kick you back...and to intentionally retard the spark at high rpm and create magnificent backfires that would rock the neighbourhood! I was bad for that one!!!!!!

When I was 13, my dad and I restored a 1948 Panhead that had been stored under a house (long story...) anyway he told me if I could start it I could ride it. So I hopped my happy skinny little 13y/o self on the HUGE kickstart pedal with both feet and jumped on it. I didn't realize that I had turned the left grip and advanced the spark as I jumped, it went 'chug chug POW' and threw me over the bars. I can see my dad laughing right now.

I got up, got back on it and started the damn thing, then rode it around the neighborhood. During that ride, the thing had two big threaded gas caps, each of them had 3 spikes, was made of chromed brass and weighed about a pound. I watched the right hand cap start spinning itself loose from the vibrations, it came off, rolled down the tank and got me right in the goolies. Ouch.

 

[XSLeo]

Capt Zoom, That might work if you got all the sensers that it needs to work off a new Triumph.
gggGary, The Harley ignitions are set up for cylinders at 45 degrees. I don't know if you could reset them to fire at 360. The ones that are "single fire" use a coil with three primary connections. Two hots, one common ground. Two outputs. Basically two coils in one housing. Some can set the timing differently for each cylinder, but I don't think they can go far enough for a 360 engine. A rephase maybe. Not sure there either.
I know that some used the same Mallory module that Pamcopete's Gerber lid ignition used. They used a rotor instead of a Gerber lid. It has two notches, not quite 180 degrees apart.
Some use the stock mechanical advancer, some use an electronic advance and can adjust the advance curve.
A bit of research on them, talk to the manufacturers might lead you to better answers.
Leo

 

[1974jh5]

As noted in my thread about the bad flat spot off of idle, I'm beginning to wonder if this isn't an ignition problem. So I pulled the TCI module and started examining it closeley, the circuit board and solder joints on mine are actually of pretty nice quality (particularly if you consider when it was made).

This module is labeled TID12-018, then 4M4-10, then 007. 4M4 means it is an XS650 part, the 007 I think is the version.

Here's a picture of the component side of the circuit board:

the back or conductor side:

and the only bad looking component I can find:

It's visible at the end of the row of diodes and resistors, right next to the gray and black capacitors. One end looks corroded and possibly overheated, the other side of the board looks fine. It looks almost as if it 'popped' and spit something out. It's a Zener diode, the board is marked 'ZD1' underneath it. My diode test function on my multimeter says I have continuity both ways on it which I understand to be a Zener property.

So my questions are: how do I identify this Zener diode to find a replacement and is it likely it could be the source of the 'won't rev up' problem I am having? One end of this diode (the '+' side) goes to the black/white wire which goes to the ignition pickup.

EDIT: FWIW, according to some Googling Zeners are used for 'signal generation'. Maybe...

 

[XSLeo]

From what I know about electronics, and thats not a great amount, a Zener diode passes voltage up to a preset amount. I this case about 14.5 to 15 volts. This protects the TCI from overloads and power surges. Like a overcharge from a bad regulator.
I have read where people have replaced the Zener diodes and fixed there TCI.
The diodes marked D1 to D4 others have swapped to repair there TCI.
You can try replacing the ZD1 and see if it helps. Radio shack sells them. Take your in and get one physically the same size, this will be about the same current carrying capacity. Get one with a 14.5 volt rating.
You can search TCI repairs and find more about it.
Leo

 

[mouser]

As noted in my thread about the bad flat spot off of idle, I'm beginning to wonder if this isn't an ignition problem. So I pulled the TCI module and started examining it closeley, the circuit board and solder joints on mine are actually of pretty nice quality (particularly if you consider when it was made).

This module is labeled TID12-018, then 4M4-10, then 007. 4M4 means it is an XS650 part, the 007 I think is the version.

Here's a picture of the component side of the circuit board:

the back or conductor side:

and the only bad looking component I can find:

It's visible at the end of the row of diodes and resistors, right next to the gray and black capacitors. One end looks corroded and possibly overheated, the other side of the board looks fine. It looks almost as if it 'popped' and spit something out. It's a Zener diode, the board is marked 'ZD1' underneath it. My diode test function on my multimeter says I have continuity both ways on it which I understand to be a Zener property.

So my questions are: how do I identify this Zener diode to find a replacement and is it likely it could be the source of the 'won't rev up' problem I am having? One end of this diode (the '+' side) goes to the black/white wire which goes to the ignition pickup.

EDIT: FWIW, according to some Googling Zeners are used for 'signal generation'. Maybe...

What year bike did this come from??? please.

 

[1974jh5]

Woops, meant to include that. It's a 1980 650 Special. About Zener diodes: a 1N4742 is 12V, a 1N4743 is 13V and a 1N4744 is 15V. Radio Shack carries only the 1N4742 but the others are easily sourced online. Zeners are difficult to properly test with a standard multimeter, there should be continuity only one way until the gate voltage is reached at which point it now beomes 2 way.

One end of this one goes to the black/white wire to the pickup coil which is why I think it separates the pickup signals until a certain voltage is reached and the pickup should generate a higher voltage signal as the speed is increased. So this may very well be the 'signal' for the IC that a certain RPM is reached and it's now time for the IC to do something different.

 

[mrriggs]

Woops, meant to include that. It's a 1980 650 Special. About Zener diodes: a 1N4742 is 12V, a 1N4743 is 13V and a 1N4744 is 15V. Radio Shack carries only the 1N4742 but the others are easily sourced online. Zeners are difficult to properly test with a standard multimeter, there should be continuity only one way until the gate voltage is reached at which point it now beomes 2 way.

One end of this one goes to the black/white wire to the pickup coil which is why I think it separates the pickup signals until a certain voltage is reached and the pickup should generate a higher voltage signal as the speed is increased. So this may very well be the 'signal' for the IC that a certain RPM is reached and it's now time for the IC to do something different.

The black and white wire is connected directly to the black ground wire. So the zener is connected between those two big resistors and ground. The two big resistors are fed directly from the red power wire. Also on the zener side of the resistors is the grey capacitor, pin 18 of the IC and many other components. The zener in this case is possibly a voltage regulator, or as previously suggested, an overload protection.

 

[1974jh5]

Now that I look more closely at the board, I see what mrriggs is saying. Damn, wish I knew more about surface mount electronics and their theory of operation. I did figure out that each of the pickup wires (white/green and white/red) has 2 diodes in its circuit (that's the 4 white/yellow Easter egg lookin' diodes). I might just replace all of them too even though they look OK.

EDIT: Soldered in a new ZD1 Zener diode and replaced all 4 'Easter eggs'; it runs exactly the same.

 

[1974jh5]

I went back and tested every connection I could find and verified voltage, ground etc. I ran the engine with first the right then the left plug disconnected (I used another spark plug, didn't leave the wires dangling loose) and got some weird spark, kind of red and thready, not the hot blue spark I'd expect. Even though both spark plugs share a common secondary winding, I got different results from the left and right plugs, the left side kept the thready red spark but the right side quit firing as the RPM increased. The coil ohmed out good. So I plugged the coil in, put two plugs on the wires which I then grounded solidly to the engine (I used wire to make damn sure), disconnected the TCI module and used a wire from the orange wire to ground, tapped it rapidly against a ground. The coil fired maybe 2-3 times and then quit. The test wire still sparks even though the coil does not telling me the primary winding is working. Both the primary and secondary windings still ohm out properly, but no spark. I'm thinking (hoping) that's my problem, just waiting for a new one from Mike's.

 

[Capt_Zoom]

Opened up mine that was giving me problems today (from a 1980 xs650 s-model). Good thing i had a working spare.

Anybody know what the heck that is that's melted right in front of the red and white wire? And a part number or link to replace it? Can it even be salvaged. Thanks

 

[1974jh5]

Wow, that's cooked pretty good. I'm going to say it's probably a resistor. There should be a marking on the board underneath, if it hasn't been cooked off, something like this: R1 (resistor 1) D1 (diode 1), etc. If it's a diode, pretty much any 12V diode capable of handling say 2 amps or better should work. If it's a resistor, they have color bands which describe their resistance and voltage. There are 2 resistors just 'downstream' of the red/white power wire in mine so I'm going to say it's probably a resistor. Since that one is fried so bad you can't see the color bands, maybe someone has a picture of a good board that will give some idea.

Resistor color band ID chart:

 

[Underdog]

wow good info here i cant believe this forum just stopped

 

[bpeckm]

Well, I just dug this thread out and it has inspired me to look further into my TCI..... project for a cool early winter's night sitting by the fire.....

 

[mrkwaka]

Wiring a bobber could not find wiring code for TCI pick up wires are .grey .orange .black. into harness changes .black and white to black.grey to white and green.orange to white and red.I could not find a wiring code so it may help others the xs is a 80 model 3go model