Ignitor Failing?

MacMcMacmac

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Well, it has been an eventful season so far. The charging system gave up the ghost (rotor....again), then the repaired rotor gave up the ghost, then the repairedrepaired rotor crapped the bed, so now the repairerepairedrepaired rotor is in and doing the business. Not before I managed to drop my headlight face down on the floor and crack the lens though. Now another issue has reared its ugly head, my bike is misfiring like a very misfiring thing indeed. It wont idle for beans, popping and farting through the exhaust before quitting like someone threw the kill switch. I can ride through it at higher revs, but the bike is intermittently nosing over, like someone is throwing the kill switch at random intervals,. It was so bad the other day I pulled off to the side of the road and held the throttle while the bike was backfiring loudly. To me, this is indicating a TCI issue. What I'd like to know is if there is a quick and dirty way to slot in a GN250 ignitor to troubleshoot the problem. They are cheap enough to use as a diagnostic tool, but i don't want a time consuming wiring job to make it happen. Any advice is appreciated.
 
Well, charging is fine. The rotor failures were all mechanical (broken wires). I bought and wired in, a GN250 ignitor to see if the TCI was the problem, but other than making it very hard to start, it did not solve the issue. I found a less than tight ground wire at the battery box. It was still attached but I could turn it without lot of force. The snap, crackle, pop of the misfiring is largely gone, but the random power loss still exists. It will start and idle fine, then just stop without warning, no backfire, no sound, nothing, like it is being switched off. While riding, it manifests itself as a distinct power loss, then shortly after pulling normally again. It`s like the feeling you get when your bike tells you it`s time to hit reserve. I tried ohming out the trigger coils but I was not able to get a reading, nor was I able to get a value from the manual. I was measuring between the white/red, black/white and white/green, black/white, and black. I assume there must be a resistance value for these pickups, and that they must be working for the bike to run at all, so I am a bit stumped. Perhaps the bike shut off in the fail condition. I read another thread from a member who was having the same dying while cruising issue, but it was not really clear how it was finally solved, as a number of parts were replaced.
 
Thanks Gary. I revisited the manual and found from the 82 schematic, which is the last year covered in this manual, that it is wh/red, wh/green, blk/wh on my pickups. Armed with your info and a different meter, I measured 652 Ohms from Wht/Red to Blk/Wht, and no continuity from Wht/Gr to Wht/Blk, so it seems I either have a bad pickup, or a broken/pinched wire from one. I'm not sure which colour combo relates to which pickup, but at its worst, I was holding throttle fairly open at the side of the road and the revs would drop and stay steady, so I'm thinking the advanced pickup is iffy. In my mind, that would indicate why power would drop off at highway revs, but it still doesn't correspond to dying at idle. I noticed a few years ago that the pickup case was swollen and slightly cracked on the visible outer side, but it did not affect running, so I decided it was not an issue. Perhaps it now is.

Jan, that was my first idea, but everything checked out electrically. I could switch it off and on while riding and there was a clear change between states. There were no continuity issues evident, or dirt or sloppy operation.
 
Aeehhh I know I sound as a parrot .but two ignitions and the ground is serviced
I am back at the regulator ... Those can be dodgy depending on type
Are we talking the stock mechanical relay type .regulator . That one I had intermittent faults on needing to dump it.
Worked fine but at higher revs warm days it went high uppsetting the Boyer Bransden dumping one cylinder.
Please disregard if i am wrong here ... just thinking out loud.
But a quick check at least nothing is loose and perhaps a reading across the battery what charging numbers are there ---Fuse holder ???
 
Well Gary, you were right about the color of the leads, orange, grey,black. Shows how one model year difference in a manual can change things. The tci wires are wht/red, wht/grn, blk/wht from the tci, under the seat, until it reaches the junction to the leads going into the tci, whereupon the wire colors change, for some reason known only to a Yamaha engineer, probably long gone by now.

Anyhow, no prizes for guessing why I had no continuity on the grey lead.



This really is a piss poor place to route wires. I have been bitten by this before and I really shouldn't have been a victim again, but I guess I'm a slow learner. Probably rage fixing after the rotor crapped the bed again. Ah well, it will be easy enough to fix. I was having nightmares of chasing this through the whole harness...(now wait for me to repost that this didnt solve the issue....)
 

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To me, this is indicating a TCI issue.
TCI when they fail in my personal experience and what I've read here and there is most commonly the engine will just stop. Usually leaning in a tight turn of course.... But it will start back up instantly with the starter while you're figuring out the turn. TCI is easy to fix usually by simply re-soldering every connection on the board. Takes experience and 15 minutes. I did it preemptively to my spare. The problem is the component leads sometimes, probably rarely, get a funny ring around them that conducts intermittently. It's unmistakable but very faint and takes a magnifier to see. Re-soldering every connection takes care of them
 
Well, it has been an eventful season so far. The charging system gave up the ghost (rotor....again), then the repaired rotor gave up the ghost, then the repairedrepaired rotor crapped the bed, so now the repairerepairedrepaired rotor is in and doing the business. Not before I managed to drop my headlight face down on the floor and crack the lens though. Now another issue has reared its ugly head, my bike is misfiring like a very misfiring thing indeed. It wont idle for beans, popping and farting through the exhaust before quitting like someone threw the kill switch. I can ride through it at higher revs, but the bike is intermittently nosing over, like someone is throwing the kill switch at random intervals,. It was so bad the other day I pulled off to the side of the road and held the throttle while the bike was backfiring loudly. To me, this is indicating a TCI issue. What I'd like to know is if there is a quick and dirty way to slot in a GN250 ignitor to troubleshoot the problem. They are cheap enough to use as a diagnostic tool, but i don't want a time consuming wiring job to make it happen. Any advice is appreciated.
I had trouble one day when the carb vacuum tube was accidentally pulled off . Is vacuum tube from carb leaking or knocked off ?
 
LOL (?). Got it all fixed and I was ready to button it all up, then I thought, I best check everything before I put it all back together.

No continuity on both coils.

The wire is fine, from the plug to the coils. No continuity through the coils themselves.

Anybody have a spare set of TCI pickup coils they would care to sell.

Bugger me sideways....
 
Imagine how frustrating it is trying to find an intermittent fault on a wire with perfectly intact insulation. This was in the orange lead, which was not the one sawn through by the chain .

Now imagine doing that with two separate multimeters with the same problem with their leads.....

:doh:🤬💩:wtf::cussing:

Well, I cut out the old wires and left about 4" of known good (ha ha...) original wire at either end of the new soldered-in conductors to preserve the proper colour coding at the alternator and plug. The stars aligned and I got 625 Ohms on both coils. I then carefully wrapped the entire lead in rubber splicing tape. Then I realized I didn't remember where the orange and grey leads went and had to clean up the mess from my hands before firing up this site and sussing it out. I routed in the new lead nice and careful like, before running two zip ties up through the center stand mount to keep them far away from the chain. It started better than it ever has and didn't miss a beat in 3hrs of riding.
I retrospect, this has probably been an issue for quite awhile, as there was often inexplicable drops in idle speed and random backfires the whole time I have owned this bike. Unless you have owned several, the best your bike has ran is the best you think it can run, so now I know better. My hot/cold relationship with this bike is now....warmish... again.
 
Imagine how frustrating it is trying to find an intermittent fault on a wire with perfectly intact insulation.
Really good meters have continuity testers that detect a super brief connection or open and latch it and give a long beep or silence. Connect up and start moving wires around, maybe pretty vigorously, until you get a change in beep. You can check the quality of that part of the meter by glancing the probes together as briefly and lightly as possible -- it should always beep if there's the slightest contact.
 
One of my meters is a Fluke 333, which is pretty good, but it is biased more to industrial/residential electrical work. The other is an RCC500, which is good enough and has served me well, but it eats batteries. Both need some new leads, apparently.
 
I managed to catch this fault on my bike before the chain cut through too much. It must have been an intermittent connection on your bike. I doubt if the tci would function at all if one of the pickup coil connection were severed. There is a misconception that one pickup is for advance and one for retarding. This is incorrect. The pickups are 25 degrees apart. The one at 41 degrees sets the top end of the advance curve. The pickup at 16 degrees set the bottom end of the curve. The advance between 1900 and 3300 rpm will be somewhere between 16 and 41 degrees, determined by comparing signals from both pickups. A good analogy is the old counterweight point ignition. There is a low end of the advance curve where counterweight are fully in and a top end where the centrifugal force has pushed the weights out. Anyway...I digress. Glad you got it working.
 
I've a had a worn borken pick up wire there more than once. 5twins found one like that also. wire was "hanging by a strand" result; flaky running, for sure a place to be looking on TCI bikes with poor running.
 
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