1983 Yamaha Xt550
 

Hi...well Being The Good Person I Am...i Am Taking On A Project From A Friend..his Son Has A 1983 Xt550....states It Runs..i Have Never Wittnessed This "running".... I Rebuilt The Carbs For The Young Man, Who Has Spent Bu-ku Bucks...tires,,,handle Bars,,,,,clutch....now Carb Kit And My Time..

Problem Is: No Spark...now I Am No Genius, But There Are Only A Few Parts Involved In Getting Fire To The Cylinder. Pick-up Coil....cdi Box---primary Coil...and Ignition Sw....now...my Question

Any Xt Owners Out There That Know Which One Of These Is Most Suspect? I Don't Like "throwing" Parts At Something, When Getting The Bad Part Replaced Right The First Time...

I Just Need Some Help With Test Procedures (if There Are Any)...to Help Me Narrow The Search

Thanks

Perry

:welcome: to the forum Perry

Speaking from experience....(former 550 owner) I'd be willing to bet that the stator or pick-up coil might be the guilty culprit......it's what went south on mine @ 1 point.:thumbdown:
If I remember correctly......there's a 300ohm value that's supposed to show @ the stator (check your manual to be sure).
From what I know, the CDI & primary coil usually outlast the stator which seems to be a common issue with 'em.

Best of Luck! :mchappy:

Hi Perry.

First spend a few minutes on google, should find an e-workshop manual without much trouble.. one is floating around on the internet.

There you have all the ohm readings of the stator/pickups/ign coil etc. Check those first, but keep in mind that it is possible (but not likely) that a coil may show the right resistance, but be shot anyway. So don't trust it 100%.


After that you could unplug the black/white wire from the CDI box, that should bypass all possible problems with the ignition switch and kill switch (you should get spark, no matter if the key isn’t in the switch or if the kill switch if on, or if the wiring is faulty etc..)

Please keep in mind that you should not kick the bike unless ignition system is all there and connected and the spark plug connecting the engine.


My ’83 550 has a temporary CDI box, since the original one was shot. I got another one used, and it was also shot. In fact CDI boxes in the XT550 and older XT600’s go bad all the time, it is a known weak spot. So your problem may be the box..

I also had an 82-83 XT550 only 3 years old at the time(the bike, not me)which ran fine up to about 120 KPH, then lost power down to 100 KPH, then accelerated back up to 120 and so on, all at full throttle.
Turns out it was a intermittently faulty timing advance circuit in the CDI. What pointed me in that direction(after trying everything else) is that I was told at the time that the CDI's are troublesome.
I know these symptoms are different than yours, but this info may be of use.
Bob

THANKS FOR THE INPUT GUYS. i AM IN THE PROCESS OF TAL;KING TO SOME BUDDIES ABOUT THIER EXPERIENCES. I DON'T WANT TO BUY A MANUAL, BUT LOOKING DOWN THAT AVENUE ALSO.

RIGHT NOW I HAVE MY IGNITION TESTER HOOKED UP A SPRKPLUG LOOKING THING WITH GROUNDING CLIP, AND THE SPARK PLUG OUT. NOT SURE IF THIS IS CORRECT...WORKS WITH ALL MY OTHER SINGLE CYLIDER STUFF.

TONIGHT I WILL DISCO THE KILL SW, AND KEY SW AND SEE WHAT HAPPENS. I AM KIND OF BEWILDERED, CAUSE THE OWNER SAYS IT WAS RUNNING PRIOR TO BRINGING IT TO ME FOR CARB WORK....THE CARB BY THE WAY, WAS A BIT TRICKY, BUT GOT A KIT FROM KEDO...CLEANED UP GREAT THE OLD FASHIONED WAY...SOAKING AND COMPRESSED AIR!!

NOE ALL I NEED IS FIRE, AND I THINK WE CAN MOVE IT OUT OF MY SHOP!

AGAIN THANKS FOR THE INPUT..MORE TO COME