Max had a stroke

[madmax-im]

Success!!

Max is baaaack! Problem was diagnosed by our resident electrical Guru Randy...it was a cold solder joint in the TCI...it was eveident when you looked at it...some resoldering and bingo... all is as it should be....PLUS...I finally installed Larry's YICS Eliminator tool ...re-synched the carbs and readjusted the idle and the bike is running smoother than I can ever remember....So once again I am much indebted to Randy for all his fine help...he found the problem within 5 mins of troubleshooting..and the YICS eliminator has made throttle response so much smoother ...I highly recommend the YICS eliminator to anyone who has the YICS system...ok time to blow out some cobwebs....See ya...

[Axel]

Told ya

Some questionable diagnosis in this thread .

[madmax-im]

Some questionable diagnosis in this thread .

Give that man a ceegar

[Axel]

Sweet

Good to hear things went well . I had Randy's web page and the forum to help me when it happened to me . I was able to use a 4RO TCI from a 81 XS with a slight modification. I have since procured a XJ TCI but havent found a reason to change back.

[DGXSER]

BNE,

Awesome that you found it and got it fixed!! I am glad for you and it is very lucky Randy is close by and could give you a hand. Since SWMBO has been laid off for 8 months now, I certainly know how tight money can get, and makes it hard to spend it on the bike. So it is great you got your TCI fixed instead or replacing it.

As to using the 81 in an XJ, IIRC, you would need to add a vacuum advance to your XJ as the advance was all built into the XJ TCI, but the 81 used vac advance with the mech advance built into the TCI.

As to the other suggestions made, every diagnosis is questionable until you find what it is, inlcuding guessing it to be the TCI. I still think the Cat-in the-Hat said it best, "the way to find that missing something is to find out where its not". Same thing goes for issues like this, you have to find out where it is not until you isolate down to where it is. The symptom was just as indicative of a bad coil or pick up coil as it was a TCI issue. And the pickup coil and the coil are much cheaper parts to buy and much easier to diagnose if they are bad.

Axel...Just happened you got it right by making a guess at the TCI, does not make anyone elses guess or suggestion less correct. Whats up with the hatin here?? Why you want to diss on the folks who offered their best educated opinions?

[Axel]

Maybe

I calls em how I sees em and it wasnt a guess .

[Axel]

Been there -Done that

You do not NEED to add anything to the XJ to make the 81 4RO TCI work .The pinout is slightly different .

[TopCatGr58]

Hey there DG,

Axel had a problem with his XJ TCI a while back, and was able to procure an 81 4RO unit instead. Yes, the XJ has the vac. adv. curve built into it's programming, and uses the special Vac. Boost sensor/box to send the required signals to the TCI instead of rotating the timing plate. But "we" found that the vac. adv. is more for finess driveability and slight fuel mileage savings. The Cent. Adv. timing curve built into the 4RO is adequate for allowing the bike to run rather effectively and within the power range of timing, just doesn't allow it to adv. as much under cruising rpm/load for that modest fuel savings! Remember, the vac. adv. actually RETARDS the timing back to the less adv. position under heavy throttle for richer fuel/air mixes, and so without the vac. adv. his timing is already there.

So.. the XJ can run with the 4RO TCI without having to utilize the boost sensor, and with just a modest change in the pinout. He's not worried about the mileage, and it hasn't really suffered much from what I've heard from him. Yes, the ideal situation would have to have swapped in an 81 timing plate and vac. adv. parts/assembly, but he's happy, and its' not really hurting his bike/engine running with just the cent. adv. curves! Just an FYI!
T.C.

[Axel]

Thanks

Thanks T.C for explaining that . I am still getting about 40 mpg (Imperial) on the right gas and am experimenting with the acetone for more (stock FD). This thread has renewed my interest in trying the XJ TCI again to see what happens . So its all good .

[Larrym]

The last place you look...

Good to hear Madmax is once again fully functional.

Ok...so it was the TCI. I know that when the troubleshooting process began the focus was on the coils/pick ups/wiring. (Moisture is always a bad thing and to me it isn't clear if it was really the cause of the stroke...not enough info.) These components were right there and the tests were made according to known standards. The tests must have shown as "good" so the process moved on to the rest of the wiring/components. It doesn't really matter which end of the electrical system is the starting point so long as the troubleshooting moves on to the other "players" in the game of controlled spark.

I'm assuming that the breakthrough came when Randy did the actual TCI test as shown on his website/video and there wasn't the proper "voltage swing" on one of the TCI output wires, right? (Again, testing has to start somewhere and only ends when you've found the defective part/wire.) Was this followed up by an actual TCI swap to confirm proper functioning?

I ask because I don't have an analog meter and wouldn't be able to see the needle swing like in TCI test video. I do have/use a Fluke DMM and it's useless for this type of test. I do have a spare TCI but don't know whether it is a "known good" part. I'm not a fan of doing "swaptronics" but if my tests led me to the same place as Madmax, I'd swap it to see if it solved the problem.

[madmax-im]

Good to hear Madmax is once again fully functional.

Ok...so it was the TCI. I know that when the troubleshooting process began the focus was on the coils/pick ups/wiring. (Moisture is always a bad thing and to me it isn't clear if it was really the cause of the stroke...not enough info.) These components were right there and the tests were made according to known standards. The tests must have shown as "good" so the process moved on to the rest of the wiring/components. It doesn't really matter which end of the electrical system is the starting point so long as the troubleshooting moves on to the other "players" in the game of controlled spark.

I'm assuming that the breakthrough came when Randy did the actual TCI test as shown on his website/video and there wasn't the proper "voltage swing" on one of the TCI output wires, right? (Again, testing has to start somewhere and only ends when you've found the defective part/wire.) Was this followed up by an actual TCI swap to confirm proper functioning?

I ask because I don't have an analog meter and wouldn't be able to see the needle swing like in TCI test video. I do have/use a Fluke DMM and it's useless for this type of test. I do have a spare TCI but don't know whether it is a "known good" part. I'm not a fan of doing "swaptronics" but if my tests led me to the same place as Madmax, I'd swap it to see if it solved the problem.

Lets address these points...While I found no moisture any where under the bike it still might have caused to TCI to "go".. We started with the TCI as its right there and easiest to access. It was determined that it was in the TCI...upon dis-assy we turned the PCB over and on the circuit side you could see with the naked eye one of the transistors soldering was discolored like it was burnt...closer inspection and you can see what appears to be a soldering defect. Given that the TCI is the original it has had years of heating and cooling and vibration all of which contributed to the "stroke" given alittle moisture prolly sent it over the edge.
We did not swap out the TCI against a known good one to confirm proper function...Randy did use an analog meter so you could see the meter swing back and forth when cranking the starter...once all resoldering was finished pin test confirmed all was in working order...Bike was started and it was firing all cylinders..problem solved...it was great that no replacement parts were needed and that the original TCI could be repaired. The only thing we were out of pocket for was Randy's time and his travel expenses to get here and me out 1 six pack of beer....it dont get any better than that

[randy]

Larrym, you're right that the DMM is useless for this test, but in a pinch you can hook in a 12V bulb in place of a meter.

[Larrym]

Great! Thanks for connecting the dots for me on this one.

Will be better prepared for when my bike has a stroke.