'81 XS 400 spark issue

[skillzman1]

Hello all,
I'm new to the forum...just bought a bike to play with...has spark on one cylinder(left) and not the right...switched the harness connectors side/side..and it moves the spark to the other coil.
So that eliminates a bad coil (?)
Traced the harness wires from the TCI...all the way back to the CDI box...found no shorts visually.
I'm not great with electrical but I do have a repair manual with the diagrams...so thats a big help in tracing circuits.
Is there a way of testing the TCI/CDI units that would be somewhat straight forward...continuity tester...or something like that?
Any advice?
Thanks, Matt

 

[drewpy]

welcome skilzman

All you can do to check the electronics, is to look for unsoldered connections.
Its recommended in the manual you don't run the electronic ignition without a spark as it knackers it up.

beg steal or borrow a duplicate to check!

 

[skillzman1]

I have a buddy thats a vintage bike mechanic...he said most likely its a CDI box....ooof!!
ebay is gettin big $$ for em right now...have to be a bit more sure before I pull that trigger...buddys coming over in a few days to check it out...

Just getting started on the bike...lots of ideas for a cafe build....but I want to hear it run before I go too far.
thanks for the info!!
-Matt

 

[Chickenone]

any word on the CDI box(Igniter unit)... which wire is working for you?

 

[skillzman1]

Haven't had the money to ebay one yet...I have the same issue as you I believe.
Everything works except the orange coil wire harness...the gray harness works ..switch sides and it powers the other coil.
I pried the CDI cover off and looked at the circuit board...dont physically see anything wrong....I know a guy local who builds and programs circuit boards...I thought maybe he could show me how to test individual diodes etc,..
will have to see what he says.

 

[Chickenone]

Haven't had the money to ebay one yet...I have the same issue as you I believe.
Everything works except the orange coil wire harness...the gray harness works ..switch sides and it powers the other coil.
I pried the CDI cover off and looked at the circuit board...dont physically see anything wrong....I know a guy local who builds and programs circuit boards...I thought maybe he could show me how to test individual diodes etc,..
will have to see what he says.

ya.. i read in the xs650 site this..


http://www.650rider.com/index.php?n...opic&t=1015&postdays=0&postorder=asc&start=48

 

[skillzman1]

well I did the test they mentioned...both transistors read the same??
put the cdi back in...got spark several times on both coils..then a little smoke from the cdi...took it out rechecked soldering points...put back in bike...spark both sides then spark in the cdi box...no more spark on suspected bad side....back to square one.
Its definately something in the cdi...probably just going to get another unit...AFTER I get a new battery to eliminate a weak battery.
Have charged it up for a few hours but its still pretty weak...forgot to test the battery voltage when my buddy was here with his multi meter.

 

[drewpy]

well I did the test they mentioned...both transistors read the same??
put the cdi back in...got spark several times on both coils..then a little smoke from the cdi...took it out rechecked soldering points...put back in bike...spark both sides then spark in the cdi box...no more spark on suspected bad side....back to square one.
Its definately something in the cdi...probably just going to get another unit...AFTER I get a new battery to eliminate a weak battery.
Have charged it up for a few hours but its still pretty weak...forgot to test the battery voltage when my buddy was here with his multi meter.

buy a multimeter, they are too cheap not to!

 

[Chickenone]

i found a cdi on ebay for 25$.... wired it in and spark on both plugs!

 

[skillzman1]

good to hear...I think that will be my best option as well.