The spark is gone....on my 125WR 78

[Joniver]

Hey there. My project 1978 Husqvarna 125WR was running intill... it stopped running yesterday. The spark was gone. I checked different sparkplug, checked all connections, and measured that I had power coming from the magnet to the coil as i kicked it, but nothing from the coil to the sparkplug. Could the coil be broken? Is that something that happens? Any tips or shoul i buy a new coil?

 

[suprize]

checked it without the kill switch? also the earths, engine mounts etc, go through all those and make sure they are good. coil would then need testing.

if its an SEM (seldom making electricity) it could have failed....

 

[Joniver]

checked it without the kill switch? also the earths, engine mounts etc, go through all those and make sure they are good. coil would then need testing.

if its an SEM (seldom making electricity) it could have failed....

thanks! I went through everything, bypassed the killswitch and made an alternative earthconnection. Any tips on testing the coil? How do I know if it is a SEM?

Thanks again

 

[visiteur1948]

possible
= key motoplat
(part number 4 )

= sparck NOS NGK

=test high voltage reel =20 ohms

=test stator = 30 ohms

=change houd candle and test

= stop engine

 

[ruwfo]

I'd agree the flywheel key broke, happens from time to time.

Husky John

 

[Joniver]

But w

I'd agree the flywheel key broke, happens from time to time.

Husky John

but i get a reading on the red wire when I kick, so that must indicate that it is creating electricity? Could that flywheel key still be the cause?

I will check the other things visiteur1948 said tomorrow. Thanks a lot guys

 

[justintendo]

yes, the flywheel is still turning working normally spark. when the key has sheared, it hasnt failed. its just a timing baseline/lineup tool. it indicates the flywheel has slipped on the crank, using from a loose nut or worn out crankshaft stub. that is why you are supposed to lap the flywheel to the crank, so it has a nice fit and requires less torque to stay in place. just a possibility. i would check the plug wire and cap first, but if you have never had the flywheel off you get a puller and check it out regardless.

 

[PawPaw]

The most common issue is that the coil mounts have rusted and not making good contact with the frame.
That contact is the ground and without a good ground you will not have spark.
Also if the spark plug cap is dirty, rusted or corroded and or has a bad connection to the spark plug wire, these too will make it not have spark.
Check and fix those first before tearing into it further..

....as these are quick and easy no cost possible fix's.

Paw Paw

 

[Joniver]

possible
= key motoplat
(part number 4 )

= sparck NOS NGK

=test high voltage reel =20 ohms

=test stator = 30 ohms

=change houd candle and test

= stop engine



View attachment 45942
View attachment 45943
View attachment 45944

Hi again
When i test the high voltage reel = 2,2

When I test the stator (measuring from the plugcap to the wire that goes to ground. And note that I have taken the coil of my bike) = 7300

What this tells me, i have no idea

 

[visiteur1948]

test high voltage red motoplat =22 ohms is good !

your test cable blue and black motoplat stator is ?

 

[Joniver]

test high voltage red motoplat =22 ohms is good !

test high voltage red motoplat =22 ohms is good !

your test cable blue and black motoplat stator is ?

The green wire = Ground

This is what i measured. As you can se the high voltage red motoplat is not 22, but 2,2 ohms

And the motoplat stator is 7300

or am i doing this wrong?

 

[juicypips]

Personally i check ht wire and plug cap in that order before assuming anything else. Good luck.

 

[Joniver]

Personally i check ht wire and plug cap in that order before assuming anything else. Good luck.

HT wire?

 

[juicypips]

The wire from coil to spark plug cap is copper/carbon core wire these on cars are ht leads. So on bikes is a???
The resistor on cap can break down, the lead can frey internally etc.

 

[visiteur1948]

mesure ohms for this
model only !sorry !