250-500cc Please help 1985 500 xc no spark.....

please could someone help i have purchased a xc 500 1985 husky which was a green lane spec 'non runner'..... its has no spark i am currently changing it to a motorcross spec bike so have took all the lights and swich gear off it.... but i still have no spark and i cannot locate a wiring diagram to look at to see if all my wires are correct...
heres what i know 4x wires out of stat 1xblue to coil , 2x black(1x to coil 1x to chassis earth) and 1x yellow (not sure where to put this.?) i have tried another coil pack which i know works and still no spark please help as i am loosing the will to live........

Yellow wire is for the lights. One of the black wires should be for the lights also. Do you have a light blue wire running from the coil to the kill switch? check that wire and your switch first, known for a lot of No Spark problems. I think I might have a wiring diagram somewhere, I will try and find it.

yep i do its not going to anything yet as i'm waiting for a kill switch a diagram would be ace thanks for your help..

Often it is the stator or perhaps the coil. The blue wire when grounded stops the spark. If the blue isn't attached it will run so long as it isn't grounded assuming all of the rest of the stuff works. Pretty much all of the dirt bikes work like this opposite of a normal street bike which puts 12 volts to the coil when you turn it on. Yellow is good for about 35 watts and usually there is a voltage regulator of sorts that goes to then more yellow to light.

You might get this moved to vingage. Maybe someone knows how to use an ohm meter on the stator wires and check that out without swapping a known good one to test.

o.k i had a re-think after your advice.. as this was a recently coated frame i re cleaned the frame up the earth point , and re - fitted my coil pack from my 390 OR , and there was a great spark ..... put my original one back on ... no spark so i think that unit has failed ... any idea's where i can locate other than expensive Eb*y

Try here. http://www.powerdynamo.biz/

Running theirs in my WR - awesome!