Not firing on cylinders one and four

can you confirm short vin on motor matches frame?
.
4H7 H
4W5 LH

 

plug it in and push the go button

 

But it doesn't go very well on two cylinders

I suspect the wiring diagrams are not correct, and that the 81 has the orange, black, grey, and brown. That is what the OP is seeing (with two of them) and last night I found one just like that on Ebay, but can't seem to find it tonight.

I believe black, green, and red label TCI's tie the two inner pins (pick-up rtn) on the six pin connector together, as well as tying them to DC rtn on the 4 pin connector.

 

I think your correct . I am thinking a solder joint has failed in the tci . if he were to splice wires together it should work for him on 1 connector. he should ohm them out to see

 

do it, it's free

 

I can confirm that the stamped VIN on the frame and the VIN stamped on the clutch case match.

It is 4H7-114782 in both locations.

 

your year does not have a sidestand switch so no black/white wire.

my 82 650 starts and runs with the Black label tci no issues.
both tabs where your brown wires connects are connected on pcb. if you were to switch the positions of the brown wires it may confirm bad pick up or bad connection of tab to pcb.

use a sewing needle to slide into connector to unlock contacts.

 

where did the metal dust come from? if the ends of the pickups are damaged the pickup may/will not work.

 

Not to resurrect a dead thread, but I'm OP so I'm doing it anyway.

Just to follow up, I finally got around to test fitting the ebay ignition pick ups. After some fiddling around I got it to fire up but not stay running for more than a few seconds. I took the petcock to bypass and got it to stay running. Guess I got some gunk there to clean or replace.

Once I had it running stably, I tested by pulling plugs one at a time. Now it stumbles on any one plug pulled, but doesn't die. I'm back to four cylinder operation. I'm not back on the road yet, since this was a test fit, I didn't route the pickups properly, they are run outside the bike, but it looks like I have my problem solved. Now it's just putting the old girl back together.

Thanks all for the help. This forum is a godsend.

 

I had the same problem with plugs 1 and 4 not firing. My bike is XJ 750 SECA 1981. All measurements were OK except one the plugs that was faulty. Replacing the plug the problem seems to have been solved, but I have some doubts about it. My next move will be the replacement of the main capacitors in the TCI unit (if I can locate them) the ones sending the signal current to the ignitors. I had the same problem on another bike with a CDI unit, where the main capacitor died out after years of service, ending with a weak spark. I managed to replace it and the bike is running perfectly. An electronics mechanic that helped, said that all capacitors tendto loose strength after a period of time.

 

go to this link http://www.xjcd.org/General_Electrical it will have links for tci repair and list caps needed

 

(problems continue below exposition) After I thought I had solved this, the problem resumed. Long story short, I'm not too proud to eat crow.

Took the carbs to church (again, but with more zealous this time), and this bike now starts and runs better than I imagined it could. Fires up in no time at all with no choke, runs great, responsive and powerful. I'm positive the zealous cleaning had the biggest impact on starting, but for those who might be curious, I have a sigma 6 jet kit now, "tuned" (for what it's worth) for my 4-1 exhaust with stock airbox and filter. No complaints, no flat spots. Ran it up somewhere past 85. On my speedo I don't know how far.

I pulled back in from my test ride, lifted the tank, connected vacuum gauges to sync, and hit the starter button. *insert sound of can of rocks* did this several more times fearing the worst then pulled the starter motor to examine it. It rattled when I pulled it out, so that wasn't great. Not sure if anyone can see, but the plastic bracket on the post on the inside is broken to pieces. Apparently I was shorting to case (it would crank now and then, but always the same final result of not starting).

Along with that, I found some evidence of damage to winding insulation on the rotor. Looks like small chips, two of them. The starter brushes and whatnot I can rebuild no issue. Parts already on the way. But what I'm worried about is that the rotor is in it's death throes. Can I reinsulate this? Do I need to? Do I need a "new" rotor? I was thrilled with how well my bike ran. It's so disheartening to swing from one issue to another.

Oh well, it's a 40 year old bike. Can't complain that much!


(with the starter back in but not hooked up, this bike bump starts and runs like a dream. I can at least still ride if I'm confident I have ten feet of level runway)