TCI/ used or new aftermarket?

Guys i need one of these. There is a place in New Zealand that makes aftermarket TCI units for the XJ's. They are around $200.00 with good reviews. Heres the link.

http://www.ebay.com/itm/YAMAHA-FJ-XJ-40 ... 3571wt_718

My ? is, would buying a working used one be better? What are your thoughts?
Also would running the dynatex coils without resistor plug caps have been bad for the TCI? I have since put new ngk 5ohm caps on and non resistor plugs.
Thanks, Dave

 

Why do you think you're having TCI issues?

I was reading your "done" list; I don't see "checked and adjusted valve clearances." Twenty-one K is pushing it miles wise if they've been neglected...

The only reason I bring it up is a couple of now nearly dead-tight valves could make you think you have an ignition problem.

 

the valves are getting done this winter. The symptoms are right on and i took the cover off the tci and corrsion! This started end of season this year. idles wonderfully and the moment i get going(say 2500 rpm) it drops power. Feels like running on 2 cylinders. But the main clue is when this happens, rpm gauge drops to 0. So i would rather not clean up and try and fix the TCI. Unfortunatlly moisture got in.

 

I love how everybody treats valve adjustment like a one-time thing.

They gotta be done every 5K. It's regular maintenance, like oil changes.

Honestly, I'd just track down another TCI unit on eBay or this site. I got my tested-good spare for a whopping $2 (honest, mis-listed) but they generally go for between $50~$100. Every now and then you'll come across somebody who's parting a bike and letting one go for like $25. Or better yet selling ALL the "relays and black boxes" from the bike for cheap. Match the one you have.

 

I dont think alot of people think about the valves since many early 80's bikes were self adjusting. Like me. But i love your write up and will for sure get that done before hitting the start button again. So how long could these unit last. If the fuse box is a big deal why not the brain of the bike(TCI)

 

Maybe we should amend it to:

Valves need to be CHECKED every 5K.
You might be pleasantly surprised and not need to do anything more than take the readings.

But, you NEED to know where you stand every 5K.

 

its on sale for 150 if you didn't realize it wasn't before...

 

Very true. I've found that the more miles the bike racks up, the less they need adjusting. The first time, expect to find 8 of 8 or 7 of 8 tight. The next time, maybe only two or three, depending on how the previous adjustment turned out. After that, I generally find one (or none) need adjusting; but it also allows you to "predict" which one will need work next and have the shim on hand.

Point of fact: Most of the early '80s bikes DID NOT have self-adjusting valves, only the Honda Nighthawks beginning around '82~'83 IIRC. All of the Yamahas, Suzukis and Kawasakis needed their valves adjusted too, but guess what? They just got ignored too. And if the shims were under the buckets (requiring pulling the cams) like the Yamaha "X" series and a lot of Kawasakis, they really never got done.

 

Thanks. Now makes my decision a little harder. Does anybody else know of this aftermarket TCI(hyperpak). And your thoughts? Just want to get back to my original ?

 

Sidebar discussions aside, I've been able to find used fleabay specials as mentioned for 29 bucks each. A while after I bought the first one, I needed it. That evening I began searching again to replace my spare and found another from the same guy I bought the first one from. Don't let yourself get hosed for a hundred or more....if you aren't in a hurry, you can find them cheap.

jeff

 

...wasn't there a member here who would repaired faulty TCI??S

 

thanks guys, i think i found one for 35.00

 

Yes, Robert was one. I don't know if he's still doing it.

 

That sounds alot better than 150

 

http://www.jetav8r.com/Vision/IgnitionFAQ.html

 

Thanks. I have that site bookmarked already. Good site

 

Yes, that's a super Link!!! I found it several months ago and I was able to get some great testing techniques from it. A wealth of knowledge and I'd recomend printing and filing with your other manuals.

jeff

 

Does it rev up o.k. with the kickstand down? If so,check the safety switch,that was my cause for same problem.

 

I would think it possible to devise a simple test bench for TCI testing that would not be too complicated. A rotating disk with a variable speed drive (variable speed router would give the necessary 0 - 12 k rpm, a couple of known good pickup coils, and a couple of known good ingnition coils to put the correct load on the unit should do it.

A CRO across the low voltage to the coils would confirm the output and turn up any mis-hits, one on each channel. Another input from one of the pick-ups would give a base signal to confirm timing advance.

"What you do with a bad one" is the obvious next question and "why would you bother ... if it works it's a good one" is the obvious answer ... but it's worth thinking about ... I think.

After all that thinking the Kiwi aftermarket for a couple of hundred sounds like a good solution, might go polish my footpegs instead.

 

Something like this I made up using a variable speed drill?
http://www.youtube.com/watch?v=lvHuHutHvVM

 

Something like that ... with a few more rpms and a bit of instrumentation ... you could use a counter on the input and output to pick up the mis-fires at 12k rpm, wouldn't need to be flash ... it's only 200 Hz.

There's got to be a dead easy way to electronically simulate the output from the reluctor pick up coils ... it wont be a pure sine wave though. I'd like to connect my CRO to the bike one day and see what it looks like. It will probably vary both in intensity and shape with rpm so to be a fair test would have to do that as well. Those footpegs need another polish I think.

 

Why use a counter to check for miss-fire? it would show more clearly on an oscilloscope.
I can capture some pickup waveforms and post them up if you want. The wide pickup tooth causes an extended zero crossing point which would create some extra work in generating. Just throwing an generic AC waveform at it caused erratic triggering.

Trying to keep things sensible, just replace the electrolytic caps and re-soldering the board should fix 95% of intermittent problems without getting too complex.

 

as long as you guys are thinking, think about a 555 timer input

 

darkfibre ...

I wholeheartedly agree with the simple approach ... but it's not being able to test it that bugs me

Some waveforms would be a good place to start, at a few rpms, say idle, 5k and 10k (or something like that). Because the frequency is low perhaps we could generate something very close with a series of digital steps, similar to the artificial sine waves generated by a variable frequency drive. I'm thinking a PIC chip with an analog output just looping through a sequence of output levels. Getting this bit right would eliminate a whole bunch of mechanical clap trap and may not be too difficult to achieve. It would need an amplifier circuit (ie. a transistor or two) on the output to get the voltage right and a bit of trickery to match the impedance of the pickup coil but so far not rocket science.

polock ...

A 555 timer is a great device for generating an initial signal ... how to skew it to look like a magnetic reluctor is the trick? Perhaps the best way is to use a reluctor to give us that wierd double zero crossing effect of the iron passing in and out of range of the pickup coil.

 

http://home.comcast.net/~loudgpz/GPZweb ... EImod.html
Might something like this be the way to go, the timing curve would be off but if it's close it would work. Maybe worse but maybe better ? Dont know how to test it except try it and see. Its made this century and it's cheap enough

 

I've purchased 2 units from the guy in NZ. My XJ kept dieing , just like hitting the kill switch at any random time, went right through the electrics cleaning , resoldering etc, & it still did it. Put the new TCI in about 5yrs ago now & it hasnt missed a beat & we ride all year down here. That was in my 750RL & I have one in my 900 now.

 

Thats what i wanted to hear. Thanks Ol_750. I did purchase a used one from a member here and it works great now. So it was the TCI. The weird thing is, both TCI covers have the same #'s on them but the circuit board itself has a different layout. Not sure why?

 

Not sure what you mean with with the above... Are you saying that you actually tried a sinewave and it caused erratic triggering, or are you saying that you haven't tried one, but you're thinking that a sinewave might cause erratic triggering?

 

I have put a few simulated signals when playing around with TCI units on the bench. The signals were generated in LabView.
What you need to realize is that the A/C signal is NOT smooth a sine wave.

On most inductive triggered systems as the rotor moves toward the pickup a positive signal is produced, but as soon as the teeth line up and starts moving apart, there is an immediate spike from the positive to the negative. This gives a nice accurate trigger point, that stays the same regardless of engine speed.

Here is a quick look at one of the pickups on Pumba at idle

 

Thanks for the info.

Yeah, I realize that the actual signal that comes from the real pickups are not sine waves, but I was hoping that a simple sine wave would work OK to at least simulate the real pickups. Now after hearing your findings, I'm thinking that may not be the case, right?

I don't remember what the input stage circuitry of the TCI looks like... I should probably drag out my notes and refresh my memory.

 

That's the signal I got too, but other than digitally I'm not sure how to simulate that cliff face as an input. I wonder whether triggering with a triangular or square wave would be close enough ... they are easy to do. A pulse width modulated signal will give the sharp rise and fall but only back to zero so that's not going to work, it's got to be something that will drop negative on the reversal.

 

Most signal generators (including mine) provide the means to adjust not only the duty cycle, but also provide the ability to bias the signal with a variable DC value. If for some reason a sine wave causes problems, then I'm sure a square shaped narrow pulse with some negative DC bias would work fine. I can easily create one of those.

Only problem is that you need two of them. Two opposite phased sine waves around zero are just easier, that's all.

darkfibre, when you bench tested the TCI, did you use Labview to create two signals 180 out of phase to simulate the two pickups?

 

looking at the link i posted before, the plug fires while still in the positive cycle, could be the negative cycle is not used, it's just there.
it would depend on how the transistors are biased, but the waveforms look close enough that the GM parts might work. it's too clod to go to the junkyard now though

 

No.
Being lazy by nature, I just treated the TCI as 2 seperate ignition systems (which it basically is), and tested the channels one at a time.

 

Really? :?: Now that's interesting... When I was messing around with one a few years ago, the input functioned like a flip-flop, and I could not re-trigger the first side without triggering the second side to reset it.

In other words, I had to alternate from one side to the other or it would not fire. I could not get successive firings from repeatedly triggering the same side. That's why I was figuring I needed two input signals out of phase.

I guess I should put that test setup back together and see what's going on.

Yeah, from what I remember, it fired only on the positive going transition and the negative swing was not used for anything.

The problem with the GM module is that you can't use it unless you've got a mechanical timing advance mechanism, which we don't have, right? Our timing advance is handled inside the TCI module, so if you switch to GM, you're static.

 

Dammit, I was certain until you questioned me on it.

My comments are based on tests done over a year ago, with Yamaha, suzuki and kwaka TCIs.

Even though i'm sure (sure?), I will retest a unit so we have uncontestable information.

 

Haha! Nice!

So we're both operating on old memories trying to remember tests that were done over a year ago then! :lol:

I've had a TCI, a scope, and a sig-gen sitting on my workbench for at least a year now. Been meaning to get back to this stuff for so long! There just always seems to be another hot fire though of higher priority.