Resistance check for TCI?

[luvmy40]

I have read in several other manufacturers' forums that a simple Ohm reading across the coil connections(back through the TCI sans coil) will show definitively if the TCI is bad but not necessarily prove it good. I.E. a low resistance reading means a bad circuit and thus, a bad TCI but a high reading just proves that particular circuit is not bad. No one could give a resistance range for good or bad, just extremely high or low.

 

Would that test prove anything on the 1983 first gen TC!?

[snyper316]

I have read in several other manufacturers' forums that a simple Ohm reading across the coil connections(back through the TCI sans coil) will show definitively if the TCI is bad but not necessarily prove it good. I.E. a low resistance reading means a bad circuit and thus, a bad TCI but a high reading just proves that particular circuit is not bad. No one could give a resistance range for good or bad, just extremely high or low.

 

Would that test prove anything on the 1983 first gen TC!?

 

From what I had noticed on previous TCI, That when it would be warm outside the bike ran like crap, or just refused to start till I left it sit. 4-5 hours later when it started cooling outside, it would fire up. Then the one day when you all got to know me it just quit. So my question would be is this, how would you know what resistance would be at what temperature? I would think where I live that when its over 90 degrees outside, and say your motor temperature at the top is 250 degrees how would that affect the resistance. I watched a guy use a hair dryer on coils while showing how to test ohms, He did this with both a good coil and a bad coil. Could it be possible for us to do the same thing with the TCI's? Just tossing something in there.:2cents:

[Flyinfool]

That may identify a bad output transistor, but that is not the common failure mode. It is usually the internal electronics that fail. it is a custom programmable IC, that can be replaced but no one knows the program to put in that IC.

[snyper316]

That may identify a bad output transistor, but that is not the common failure mode. It is usually the internal electronics that fail. it is a custom programmable IC, that can be replaced but no one knows the program to put in that IC.

 

Ok, What does IC stand for?

Sorry I'm assuming maybe Input Chip.

[bongobobny]

No, IC is Integrated Chip. What that means is an entire electronic circuit, transistors, resistors, capacitors, etc that make up a particular electronic circuit for some function or another is Integrated into one "Chip." IC's range from simple 3 legged voltage regulators or 8 legged basic operational amplifiers (op amps) to extremely complex chips with over a hundred legs such as computer process chips, etc...

[snyper316]

No, IC is Integrated Chip. What that means is an entire electronic circuit, transistors, resistors, capacitors, etc that make up a particular electronic circuit for some function or another is Integrated into one "Chip." IC's range from simple 3 legged voltage regulators or 8 legged basic operational amplifiers (op amps) to extremely complex chips with over a hundred legs such as computer process chips, etc...

 

Thanks Bob.. Now you have refreshed my memory my Mom used to run an automated machine, and if memory serves me right would insert those onto the Circuit Boards. I believe the ones we did 8, 12, 16, and 20 legs. Are they by chance black pre-programmed chips and would kinda remind someone of a centipede?

[Flyinfool]

That is them.

[bongobobny]

I'm soooo old when I studied electronics in High School IC's weren't around, and we learned vacuum tubes! Then we were told about this new device called a transistor and explained that they worked the same way as a tube, but they would never replace them...

[snyper316]

I'm soooo old when I studied electronics in High School IC's weren't around, and we learned vacuum tubes! Then we were told about this new device called a transistor and explained that they worked the same way as a tube, but they would never replace them...

Crazy thing I knew a guy who has a working Cb radio that had tubes. He may have passed but he loved the tubes.

 

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[garyS-NJ]

There's a few links on testing tci's.. You can definitely test coil resistance and I think the hall effect sensors as well as the wiring from the Tci connector. Yes the Tci outputs are transistors which should read open. My Tci died where it would not advance the ignition. It wouldn't rev and I could see the timing mark just jitter but not advance. I tried resoldering & replacing diodes, then caps, then transistors. I also tested and swapped the vacume sensor. Replaced tci with Ignitek. And yes coils often fail open when hot.

 

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[luvmy40]

I've got to get her back together and running again, but it sounded like she was only hitting on 3 cylinders at idle and low throttle but every thing sounded good at WOT. I had spark at all plugs and got a good sync but was still missing badly at idle.

 

Three of the coils tested bad on the bike but then tested good at a later date off the bike. I have another set of coils and caps and new wire. I'll put together a set with the best numbers I can.

 

I cleaned the carbs(twice) and got new air screws as the o-rings were in very bad shape and one was missing the spring. The diaphragms all looked good and they pass the swish test.

 

All but one of the 16 valves were out of spec. A couple were severely out. One is near zero clearance. I have the shims to bring them all back to the max speced clearance(hopefully).

 

The TCI connections were hideously nasty. It looked like it had spent a good bit of time under water. I cleaned them up as best I could and will probably revisit them before I put everything back together.

 

My past experience with the Yamaha CDI/TCI boxes is that the bike either runs or it doesn't. I see that may not be the case with the Ventures.

 

I hope to have everything back together for a test run later next week.