Electrical issues... please HELP!

you've got mail !

 

Thank you. I read it and sent a reply.

Can u clarify "resistive plug caps" for me? Is it the actual cap that snaps onto the spark plug at the end of the plug wire? Does my 83 750 maxim have these?...if so doesn't it require special spark plug? (which I don't believe I have)?

 

Resistor plug caps have a little cartridge in them that is really a 5K ohm resistor. Resistor plugs have the same thing built into the white ceramic part of the plug. The idea started back when grandpa listened to the ballgame on his nine transistor am radio and got static from ignition systems a quarter mile away.
So now we have "suppressed wires", resistor plugs and resistor caps but no more nine transistor am radios. But some vehicles have some pretty sensitive electronic gadgets that the same static might mess with. The resistance is to cut down that static. I've run mine every way there is, non this, non that, resistor this, resistor that and can't tell the difference at all.
The only thing you don't want is suppressed wires with resistor caps and resistor plugs, that might be cutting down the power available to make a good spark

 

Oh, your questions. yes if their original and say ngk on them they most likely are. look up inside them for a screwdriver slot, they unscrew and you can clean that resistor up. no special plug needed

 

Ok...Yes i can see the screw driver slot. I'm pretty sure they are original caps but they don't say NGK... I think I found my problem... Or 1 of them... Can the resistor in the cap go bad? One is clean one is black... Full of soot. The clean one registers something on the ohm meter.... Black one nothing! Can I jump this resistor (replace it with a piece of copper the same size? Also only 1 coil pack has these resistors in it. Does that make sense? Only wires #1 & #4 have resistive plug caps. The other plug caps for 2 & 3 don't look the samas as far as the slot inside and they also differ in size. This is correct I hope?

 

I mis spoke in previous post... Plugs 1 & 4 do not have resistors .... Only 2 & 3.
This is what the inside looks like. I can't get a resistance reading from the black one.

 

Thanks 'Polock' - I'm increasingly of the view that your kind offer will finally 'put this one to bed' (and yield that 'watertight' final diagnosis we were all seeking - given the often 'fickle' nature of faults involving electronics...)!... Judging by the photo Pat uploaded earlier, his Haynes manual lay open at the pages covering the pickups - so, we trust, he will hopefully have them 'in the frame' or 'confidently ruled out' by now!?... He also stated that he has a VRLA ('glass mat/gel') type battery; yielding (it appears after standing 'a few days' since the last charge?...) a 'perfectly reasonable' 12.47 volts: 'at a distance' that would seem to indicate that 'all is well' on the charging system front - and it had just run down on repeated use of the starter?!?... All good so far - with any 'frying tonight' scenario (as a consequence of 'over-volting') very soon to be 'confidently ruled out' completely?...

I'm a 'newbie' to this particular range of bikes - and I really only have experience of my XJ900F to go on!... It would appear (from other members' inputs...) that there ARE differences in specs. ref. pickup coil resistances - but can you tell me whether or not I'm telling Pat correctly concerning wire colours and the like?... Many thanks!

Another member was of the opinion that a faulty pickup should not cause the TCI to 'permanently power up' the coils? I did, seemingly, (admittedly in VERY hurried tests intended to firmly - or not - 'rule out' the pickups...) somehow manage to create such a scenario; but this might have been a 'spurious event' resulting from a 'surge' condition (given my repeated turning 'on and off' at the 'kill' switch...)?!... Given the 'single spark phenomenon' Pat has been witnessing IMMEDIATELY following his breakdowns (upon cutting ignition or 'kill' switches...), he MUST be getting 'fault-free' power to the TCI module/coil pack feed?!!

On my machine the black/white wire that comes directly from the TCI module will be 'grounded' through the relay whenever the sidestand is deployed (sidestand up = 'open circuit' on TCI module black/white wire...). I also have a yellow/black wire to my tacho. from the TCI module - thence to ground via the rev. limiter contact. In the (unlikely!?...) event that your substitution of Pat's TCI module should - in some way - prove to be inconclusive, these two wires have to be the ONLY potential factors not already discounted on our firm evidence?

'Static grounding' of the black/white stand 'safety interlock' wire would be expected to produce 'no change' - with 'crankshaft rotation sensing' already producing a 'coil pack interrupt' anyway? Any suspicion of this function could readily be dispelled by simply unplugging the relay connector?...

Logic suggests that if ANY function should ever be wired to 'interrupt the interrupts' (thereby 'permanently powering up' both coil packs...) it would be the rev. limiter: a straightforward 'reversal of (-) grounding status' on the yellow/black should quickly confirm or deny this - if thought relevant?

Many thanks indeed, once again, for your anticipated help in getting Pat's electrical components checked and/or tested - and I trust that my input/comments help you!?!

Regards and Best Wishes for now, Andy.

 

Some resistor caps CANNOT be taken apart. Don't ask me why, it Is what it is...............

 

THIS IS A REPLY I SENT PAT K. - AS PART OF OUR 'CONVERSATION' YESTERDAY:-

Simply stated, ANY automotive ignition system effectively embodies a similar set of components to those which were used by the 'Titanic' in April 1912 - to transmit by 'wireless' the very first S.O.S. message ever! The difference is that on the 'Titanic' they wanted the sparks to generate radio waves. On your bike we desire the sparks to fire your motor: NOT create 'snow' on your neighbours' television sets, 'buzzes' and 'crackles' etc. on their radios - and a whole spectrum of R.F.I. ('radio frequency interference'), having serious potential to 'corrupt' electronic equipment in general; including the TCI unit, etc., on your own machine!!!... For this very good reason all 'spark-based' radio transmitters were 'off the air' around 1923 - and duly outlawed internationally by 1929.... Any device with the potential to create interference (be it an electric motor or automotive ignition) was 'increasingly required' to have such R.F.I. 'adequately' suppressed - which, in the case of an ignition system, is generally achieved by introducing a resistance (or resistances...) into the HT (coil secondary) circuits. This is where 'suppressed' spark plug caps - and/or an alternative similar measure - will be provided somehow!?!!...

On any motorcycle a 'weatherproof' spark plug connector is essential - and usually a 'suppressor resistance' will be built into it during manufacture?... (NGK provide PDF downloads concerning their range of plug connectors....) Alternatives are a 'carbon-string' (rather than wire...) HT cable - or a 'suppressor resistor' within the spark plug itself. Over time these resistances start to break down - with the result that the test voltage (9v.) from your multimeter may never make it through (though, up until it gets really bad, the HT voltage will 'jump' the break MOST OF THE TIME - you being oblivious to any noticeable misfire!...)?...

This may well explain your perception of an 'open' circuit on one coil HT! You must consider, though, that all such suppressor breakdowns HAVE the potential to create 'an easier route' for the spark discharge - back through the TCI module!?!... If yours DOES turn out to be faulty, this may very well be the instigating prime cause?!!?...

 

why not just get 4 new 5K resistor caps.....& use non-resistor plugs.....& be done with that part of the equation......then caps & plugs will not be your problem anymore....

 

Ill buy new caps or new plugs or whatever else I need to buy to get back on the road. Just dont want to buy parts I dont need. I've been having trouble trying to locate the problem parts as well as locate the "gremlin" or reason why that part went bad because as we all know electrical issues have a way of being contagious when they appear and take out other electrical components on there way out. In a nutshell I want to fix what's broken on my bike but I also need to know why it broke or what caused the failure so it doesn't happen again to the new parts.
I have a scenario. Forgive me as this is my 1st XJ... hell it's my first bike for that matter. I found the plugs I pulled out of the bike a year ago the previous owner used plugs with resistors in them (BPR7ES). I switched to BP7ES without resistors. My source at the time (unfortunately NOT XJbikes.com) said to run the BP7ESs so I did but I never checked them against the plugs that were in the bike when I bought it. Plus when it fired up and ran fine for 1000 miles I assumed all was ok.... Until now.
Could using the non R plugs have caused me all these problems? And did I also ruin my TCI in the process of frying the resistor in the plug cap? What's my best option? Buy 4 new R plugs and 4 new plug caps and hope the TCI isn't toasted yet? I feel like an iddiot. I'm a newbie to bikes but I've been around motors my whole life. If I caused all this because of the wrong spark plugs man do i feel stupid. WONT make this mistake EVER again

 

If it were me......I would buy 5k resistor caps......& run 4 BP7ES plugs ( these plugs are non-resistor plugs )......& you don't know if your TCI is toast....send it to Polock ( do you like how I am pushing your name ).....he said he would test it for you.......

If it is a question of trust, everyone here is trustworthy, he will test for you & then send it back to you with the results........why don't you do this ???

I sent mine to K-Moe, a year ago, he tested it & sent it back no problem... I gave him $20 for his time & trouble....however he wanted nothing in return....

Put your trust in this forum & anyone who wants to help you.....

I have an '82 XJ750J Maxim......I run 5k caps with 4 BP7ES plugs...runs great......yours will run great too....be patient......this all takes time......do not get frustrated.....my restoration took 2 yrs....

 

did you ever turn on a light and it goes poof, stuff happens.

probably not, if that were the case there would be a whole lot more people with bad tci's.

 

resistors do fail. It's just part of how a resistor works. Replace the bad resistor if the caps are otherwise in good condition. You had one good grounding point via the other wire on that coil, so the TCI is not likely to have been damaged as a result of the burnt out resistor.

 

It's definitely not a trust issue... I could tell before the offer of swapping parts came about Polock and everyone else I talked to on this forum was trust worthy. It's more of an ego thing I guess... I'd like to fix it myself with the help and advice from you guys if possible... I enjoy wrenching on my bike, I like the feeling of accomplishment when it all goes well. But yes, if all else fails Polock will be my saving grace. We actually spoke briefly about me sending several parts (not just TCI as originally offere) I'm just trying to exhaust all options before I throw in the towel and let someone else fix it. It seems i find a new piece to this puzzle every time I work on the bike.
That being said if I get new caps and new plugs, do u guys think I'll have to do anything else or was running the wrong (Non R) plugs the cause of my original problem ??? ie: bike dying and not restarting until hours later

 

Your plug choice has nothing to to with the issues you are facing. What you have is a motorcycle that has seen three decades of use, and maybe three years of the maintainance schedule being followed. Even then parts fail due to use and age. You just have to take the time to get it all sorted.

 

For $21 I just replaced them all. Didn't have time to fire bike up yet but she's almost back together. I'll update asap....

 

fingers crossed........

 

"Now this is not the end. It is not even the beginning of the end!... But it is, perhaps, the end of the beginning?"
WINSTON CHURCHILL - 1942.

There appears to be a degree (potentially 'fatal' to delicate TCI 'front-end' silicon!) of misunderstanding on how the HT circuits operate: there is not a (+) positive HT feed to all four plugs - with 'grounding' (circuit completion) through the cylinder head of the engine! If you imagine your coil packs as 'intermittently energizing' high-voltage batteries, the two HT plug leads represent the '+' and '-' terminals. It is NOT the case that the mounting bolts of the coil packs also form the '-' (ground) connections - via the frame - to the cylinder head; with the two HT spark plug leads (from either coil) BOTH providing '+' (positive) feeds.... For each coil, one HT plug lead is positive and the other negative; so for each coil circuit (a: cylinders 1 & 4, and b: 2 & 3) both plug HT leads, both connector/suppressor caps, and both spark plugs are 'wired in series' via the cylinder head (which is 'grounded' to the 12 volt battery negative terminal)....

It follows, therefore, that upon any firing discharge one plug lead (of 1 & 4, or 2 & 3) must be at a potential of 'X ÷ 2' kilovolts '+' positive relative to '12 volt ground' - while the other plug lead (its opposite number) must be at a potential of 'X ÷ 2' kilovolts '-' NEGATIVE to '12 volt ground' - the metal of the cylinder head being 'centred in the path' of both coil HT secondary circuits!...

The environment that the plug connector (or suppressor) caps operate in is NOT the most amenable!... How would YOU take to being sat (for possibly thirty years unless you've been replaced...) with a blowtorch under your butt, up to 150 'mini lightning bolts' per second hard-wired to your anal epithelium, and water splashed into your face every time it rains?!!?... Quite!!!... HT suppressor caps became commonplace in the decades before suppressed ('resistive') spark plugs became an easier option: they DO need to be considered a 'wearing part' - and accordingly replaced as necessary!?!

'Polock' made the important point that it is NOT a good idea to introduce too much 'suppressor resistance' into your HT paths (as if you do the spark discharges will be 'inclined to seek an easier route' - i.e. back along the LT wires to the TCI module...)! If your TCI module does turn out to be your problem, your 'burnt out' resistor offers a plausible explanation; BUT BY NO MEANS a guaranteed one!??!... Your soot has been generated by the spark energy 'arcing its way around' the cap resistor - rather than passing reliably through it! A cumulative resistance of ten K.Ohms will be perfectly adequate: I suspect the new NGK caps will be 5K. each - so you DO NOT NEED/WANT 'resistive' spark plugs too! I tend to go the non-suppressed connector cap path these days, with 'resistive' plugs: this means my suppressors get changed - with the plugs -before they have any chance to burn out!

Using BP7ES non-resistive plugs will NOT have caused your problems: perversely, it probably avoided a noticeable misfire!??! The cumulative effect of 15K.Ohms plus a 'burnt out' cap resistor would have led to greater (rather than less) 'back-circuiting' though the TCI module?!!?... The problem you have 'nailed' thus far is not, however, the primary cause of your breakdowns: a fault with one coil pack and its associated HT circuit would result in 'cutting out' - or misfiring' - affecting one pair of cylinders.

How did you get on with checking out the pickups - as I previously described?... Any suspicion of a sidestand 'safety interlock' problem can be dismissed by unplugging from the relay (under the seat: red/white, blue/yellow, black/white, black wires)? If you have a rev. limiter (yellow/black wire from TCI module on my bike...), 'earthing' and/or disconnecting this from the tacho. itself will reveal any fault in the contact?

Hope that helps - and good luck!... Andy

 

I checked my coils. Now that I installed the new plugs caps both coils read within spec for both primary and secondary resistances. I installed them on the bike and she fired right up. I checked voltage at the battery. 12-13 volts at idle.... Approx 13 volts at 1500-2000rpms.. 13-14.7volts at 3000rpms & higher
This makes me assume my coils as well as my battery/alternator/charging system(s) are okay. Maybe I wasn't getting solid readings during previous tests due to bad resistors in plug caps???
Next, I had some confusion as to how to check pickups. I knew they were located behind the Yamaha cover down on the crank. I had read somewhere (during my uncountable hours of research) that these old Yamahas had a different kind of pickups that were NOT SERVICABLE...meaning I didn't have to remove stator cover to check them as there were no "points" or "pickups" to adjust or reset. So when you guys refer to checking the pickups you must be referring to checking the white plug connector at the end of the wires that comes from the stator cover correct???

 

The TCI has 2 plugs into it. One is a 4prong plug.... One is a 6prong plug. Both have only 4 wires into them.
4prong - red, black, grey, orange
6prong - black/white, black, grey, orange
What wires do I test? Do I really need to open side cover to find out?? I'm becoming increasingly irritated at my lack of knowledge leading to confusion with this stupid bike. I'm about ready to send her old ass to the bone yard and go lease a new one. Every test I've run seems to check out and be within spec yet this piece of shit won't go a half mile without shutting down on me. Maybe it's about time I take Polock up on his offer as I am obviously incapable of figuring this out.

 

I would say you are learning and making progress.

You can check the pick-up coils at the 6 pin connector - Black to Orange and Black to Grey, each should be 650 ohms +/- 20% and none of them should ohm to chassis. The extra B/W wire is part of the safety circuit and when deployed provides a ground at that point to disable the TCI.

The 4 pin plug R/W to Orange and R/W to Grey to check the ignition coil primary circuits.

And, back to your original problem of the bike shutting down after a short ride the TCI is still high on the list. Don't feel like this is kicking your butt, as none of us could really verify this other than swapping it out with another unit or by trying it on another bike. So don't feel like sending it to Polock is giving in.

 

Hi Pat, your wiring colours are obviously different from my XJ900F. Check out the wiring diagram in your Haynes manual - and I will hazard a guess as to which are which: please check that I am right before you proceed with the tests!??!...

6 way, I think, will be as follows:-
Black/white: sidestand 'interlock' relay;
Black: negative '-' main feed connection;
Grey: coil pack re. cylinders 2 and 3, plus rev. counter (tachometer);
Orange: coil pack re. cylinders 1 and 4.

4 way, I believe, will be the ones to test?...
Red: + positive feed from 'kill' switch (also positive feed to coil packs...);
Black: pickups 'common' connection;
Grey: pickup ref. cylinders 2 and 3;
Orange: pickup ref. cylinders 1 and 4.

You do not need to remove the left crank cover unless/until the pickups return an 'incorrect' reading: unplug the 4 way and check the black, grey, and orange wires at the connector.... I have described the test procedures 'in depth' through my earlier posts! Again, check what your resistance readings ('Ohms') SHOULD BE using your Haynes manual!??!...

If 'Polock' and/or 'K-moe' spot this - would you be so kind as to reassure Pat I've got these wire colours/locations correct?!?...

Many thanks indeed!... IF your pickups do turn out to be OK, then dispatch your TCI module to 'Polock' for confirmation that it is faulty!??!... Don't 'give up' on this great example of fine Japanese engineering!!!...

From what you say your charging system and other components look OK!?!... I'd lay a bet it will be your TCI or pickups?!! Just stay calm, focussed, and methodical - you WILL 'get to the bottom' of this problem!...

Happy hunting!... Regards, Andy.

 

Looks like 'Rooster 53' has just confirmed which orange/grey/black wires are which!

Many thanks indeed for that - and forget about what I said regarding a rev. limiter connection: it seems you don't have one!

You are always best advised to check with your Haynes manual wiring diagram - so you have absolute confidence in yourself that we have advised you correctly!... It is going to be the connector 'with the red' - or the connector 'with the black/white' (so if you 'take it all calmly in your stride' you can't go wrong really)!??!... There you are: SORTED!!!... Best Wishes, Andy

 

If your TCI does turn out to be faulty you might feel inclined to see what else may be available - as a performance/reliability upgrade?... I'm running a 'Dynatek' fully programmable system on my extensively breathed upon 'Kwikas*uki' 1200 Bandit 'trackday special' weapon.... I'm looking at having to upgrade the swingarm - to stop it 'springing about' under the sheer 'grunt' this beast kicks out! Have to lengthen my sleeves each time I take it for a blast (lol)!

Seriously though - I don't know what the replacement supply situation is like your side of the pond?...? If you should run into difficulties there are fantastic alternatives available - and with more recent models they CAN be considerably LESS expensive than the original 'genuine' parts!... Worth looking into - BUT AGAIN, I don't know if the same 'cost balance' applies where you are: I'm in 'motorsport valley' in the UK!...

Cheers for now!... Busy day with 'Formula Student' at Silverstone tomorrow.... S*** - it's 'today' now!... Check it out!... Andy

 

What happened?? Is it over yet?? My head is spinning and I don't think I can get up!!
I swear to God I will never, never, never ever type 'XJ700 rough idle' into the forums search window again.

 

then you said

well sir you just checked them. unless you have a connection or heat problem, they're going to check good with a meter if they run the bike.
and while we're at it, post the #'s on your tci so someone that knows could tell us if that is the correct one for that bike, ya never know.

 

No no no... I checked out the coil packs... Installed them back onto bike. It's the "pickups" I'm not understanding... Something down under the Yamaha cover by the stator

 

Ya know Polock... This scares me! I've thought about this scenario since day 1 of my problem. Then on day 14 or so my bad feeling about wrong parts was somewhat confirmed... How & why did the P.O. run resistive plugs??? Wouldn't they have had problem?? I'll get the numbers as soon as I get home from work at 6am. I'll also post my ohm readings from different tests. Hopefully we will be much closer tomorrow. I want to ride so bad!

 

You checked the pickups coils when the bike started. It's called trial by fire or the proof is in the pudding......
when the bike starts 99.9% of the time those will check good with a meter. When it don't start, then they might check bad. Might.
how and why...he didn't know any better.
would he have had a problem? Maybe not if the resistor in the cap was still good.

 

Ok. I understand you now. Yes the bike starts. Proof is in the pudding that it all works for a few mins. Without doing anything (i don't move it, put it in gear, put the kickstand up, etc, I don't touch it period!) and it runs for about a minute then poof... Shuts off like someone hit the kill switch... No sputter, no hesitation, running fine one minute off the next.
I am heading to garage now. Going to get numbers off my CDI (aka TCI) to post for you as well as resistance readings from pickups. Ill update again shortly....
Let's say my TCI is bad. Would you suggest I buy a new aftermarket one?? What do other guys do in my position?? I'm hesitant to buy a used electronic part from a +30 yr old bike. Any reputable websites for used parts you guys have used in the past would be greatly appreciated

 

I think Chacal at XJ4ever sells tested TCI units. I could be wrong, but I think they test them on a bike to be sure they're functional. Maybe I'm remembering something about coils instead.
Or maybe not. I couldn't find 'em. Here's the link:
http://www.xjbikes.com/forums/threads/xj-parts-catalog-section-d-electrical-system.44641/
Ignition and coils start about half way down the page.

 

ya know if you save that file to your HD it goes way faster

 

I have 658 Ohms orange to black and 669 grey to black

 

I don't know how well you can see but the bottom left corner looks to have had water in it at some point maybe.? Can I clean this up? Should I remove nuts to inspect other side? There is a layer of glue over them. I didn't know if I should crack them free? Any advice? (besides what I should have done 2 weeks ago and mailed it to Polock)

 

Hi Pat, continuing our 'conversation' of a moment ago: yes, you do have a corroded PCB track - and, for someone who knows what they are doing with a soldering iron, that is eminently repairable!... Actually it is 'good news' - because we have a readily identifiable cause, that is not down to any 'bruising' of components caused by rogue 'back discharges' from the HT circuit that had the burnt out resistor. I think 'Polock' will have no difficulty confirming what - it appears - we now already know; and I am sure (upon checking your component layout the other side of the circuit board) we will discover that an 'open circuit' on that track will 'kill' your TCI interrupts!?...

These TCI modules (like most things on a Yamaha 'XJ') are quality well-engineered components - which is why we love these bikes, and want to hang on to them!...

What I personally love about these older bikes is that such componentry can easily be 'got at' for service/repair!!!... Yes, water can (and sometimes does!...) get into them too - but if that was your average modern part, the whole thing would likely be fully encapsulated in epoxy resin: any thought of repair would be a total non-starter!!!...

Pity I'm this side of the pond!... Search out the 'rock'n'roll fraternity' for one of those people who restores and repairs vintage sound equipment. He will have no trouble with that - and will likely 'shellac varnish' the PCB to keep future corrosion/water ingress at bay!?... Good luck, Andy

(PCB = 'Printed Circuit Board')

 

By the way, your pickup coil resistances look right on the money: if you get similar readings (which I'm sure you will!...) right after the bike has cut, that is another area we can comfortably 'rule out' as a cause....

My ignition module is different from your unit: mine is a: 'TID14-37 ~ 58L-10'

 

The nuts hold the driver transistors heatsink and should not be removed. To pull the CCA there are two phillips head screws on the back that are removed and you must also de-solder the connectors - so no to that unless you have decent soldering skills.

Hard to tell from the photo, but I would give some of the connector pin solder joints a marginal observation. They really need to be inspected under 3ox magnification or greater to look for broken joints at the top of the fillet to the connector pin. However, if you have some soldering skills I would go ahead and reflow those 9 pins.

Yes, a little isopropyl alcohol and an acid brush should be OK. Since there is no green color present on the joints the amount of corrosion appears to be minimal. Technically, the area should be cleaned and inspected under magnification, repaired if needed, and then re-coated with a product compatible with what was originally used.

 

Hi again Pat.... By the way, DON'T touch those nuts! They hold the main switching transistor heat dispersal ('heat sink') 'fins' to the PCB; NOT the PCB to the case!... You would also need to unsolder all connector 'legs' from the board too (they secure the board into the case...).... I think you have probably done as much as you can now - and unless you feel comfortable wielding a soldering iron, you would be better off leaving it to someone 'professional' in the electronic repairs field?!!?...

All the best for now, Andy

 

Most TV repair shops will do the work for a reasonable fee. The older the shop is, the more likely that they have someone who isn't just a parts-changer.

 

Ok... So before I even read these last few posts I put the cover back on the TCI and installed back on bike. I figured opening it up more, when all I would get was a better view (considering I don't really even know what I'm looking at or for). was not worth possible damage. So I reinstalled it. I then checked every possible connection... AGAIN. I also disconnected and reconnected all relays. Again. I fired her up and let it warm up... Then took an hour ride around the neighborhood!!!!! SHE RAN AWESOME! Would not die. I stopped a few times. Restarted. Ran fine. I'm completely stumped! It's great it runs good now but for how long? I don't trust it without having "fixed" or "replaced" anything. Yet another reason I HATE ELECTRICAL !!!!

 

Yeah, I wouldn't feel confident on a long ride just yet. You didn't mention a soaking or rain at the start of this thread, but perhaps opening up black box for its photo shoot allowed any moisture to dry up in there. Give it a few days of short rides so you can see if it's going to happen again. Then at least you're not high and dry (or wet...) hundreds of miles from home!

 

What you have there is called a coincidence. Moving the TCI likely also moved components that are loose on the board. I would not consider that to be a repair. Bad solder joints and/or lifted traces can move back into place temporarily and NEED to be addressed or you WILL end up stranded somewhere.

 

Agree with K-moe. Just didn't want to spoil the weekend... ride it (a bit) and then get back to fixing it.

 

There's a relay located right under the regulator/rectifier & the TCI. At 1st I thought it was the side stand relay (as it has a blue/yellow wire as 1 of the 4 and the sidestand switch IS bypassed when this relay is removed) but upon further research I believe this to be the "starting circuit cut-off " relay????...... I have a very strong intuition that this relay is also the home to my electrical gremlins!!! ..... whatever this relay turns out to be. The Haynes manual I have is for all 650 & 750 xjs, from 80-84. The book is well written with easy to follow steps for testing and repairs but can be a bit challenging to find your exact model among the several different types. Each model has different relays, in different locations and I must have overlooked this section thinking it was for another type of bike. The bike hasn't died on me yet but I believe when it does this relay will be the culprit

 

The Haynes is wrong (about several things). That is the headlight relay.

This link will help you identify the relays http://www.xjbikes.com/forums/threads/the-ultimate-relay-switch-sensor-and-diodes-guide.27543/


EDIT: Actualy I'm wrong. I forgot that the Maxim has a different relay arrangement. That is inded your sidestand relay. It could be that the wiring to bypass the sidestand switch has a momentary fault as well.

I'd still have the TCI tended to; at least reflow the suspect solder joints.

 

Polock, K Moe, Organgrinder, Rooster and anyone else I'm forgetting to mention... You guys were all spot on!! It's my TCI! It's been "acting up" shall we say? I thought it was that relay because a few times I pulled it & the bike would die and not restart... Sometimes it would only run with the relay out... Then other times it would only run with it in.... So I got to thinking... Since the relay is located right under the TCI & mounted on the same plastic board... Was it ME just moving the TCI ever so slightly that would get it to run again??? Well I pulled the relay and rode the bike til it died... I gave 3 taps with my fingers on the TCI and boom she fired back up and has run ever since. So technically I haven't "fixed" anything but I know without a doubt the TCI is the reason for the spark failure. (my relay may be faulty as well) Thank you all for your help. You guys know your SH*T!!!!