74 Z50 no longer has spark?

Joined
May 10, 2001
Messages
889
Likes
0
#1
Well, about a month ago I tuned up my 50, New plug, carb kit, rings, and some other things cleaned up the points and that. Well, it ran prime for a good wile. Then about last week I was ridding it hard and it got real hot and was misfiring real bad. I let it cool off for a few hours then tried to start it again, it woulden't. :think: I polled the plug and wasn't seeing any spark against the cly. I cleaned all the wire connections and inspected all the wires for cracks and checked the ground and all that. Put it back together still no spark. I'm getting power from the stator (held a voltage tester to the wire that connects to the voltage regulator) so I'm at a loss here. Any one have any ideas? Thanks
 

Jon K.

Subscriber
Joined
Mar 26, 2001
Messages
1,354
Likes
4
#2
Z-50 with a voltage regulator? You got a battery on that beast?

I bet what has happened is the points have closed up. The points cam is behind the flywheel and will get rust on it. Usually because the chain has come off and poked a hole in the mag cover, allowing all manner of mud and dirt and stuff into the mag.

The rust will cheerfully wear away the points breaker block (the fiber looking thingie that rubs against the cam lobe).

You can check your points gap (.020 is about right, it is supposed to break on the "F" mark) through the holes in the flywheel, but if you do indeed have a rusty points cam the flywheel will have to come off and you must polish the cam. Scotchbrite it for fifteen minutes or until you get a nice smooth finish. Dab a little grease on the felt to keep it happy.

Oh, and make sure to look at the engine case and cover to see if there is any chain damage. Sometimes you can fill the engine case damage with Bondo. The cover is best replaced, as they are pretty cheap if I remember right. $20.00 or so.

Keep us posted. :)
 
Joined
May 10, 2001
Messages
889
Likes
0
#4
No, no battery. . . I honestly don't know what it is if its not a regulator. The box type thing that is connected to the spark plug wire and connects to the points and all that. That is what I am talking about. Also its a brand new plug in there gaped correctly with no ridding time on it. I planed on pulling the fly wheel today but I had to paint so it will be tomorrow that I work on it.
 
Joined
Nov 6, 2000
Messages
81
Likes
0
#5
Don't assume a new plug has no problems. I would stick another one in there & try it. Very small chance 2 plugs are bad though.

TT
 

JuliusPleaser

Too much of a good thing.
Joined
Nov 22, 2000
Messages
4,392
Likes
0
#6
MM, the 74 Z50 has no rectifier or battery. The part you are talking about is the ignition coil. It's mounted on the frame under the gas tank, right? If you have fire coming from the stator, then your points should be fine. The coils are pretty weak on the early Z50s, so I would test that next.
 
Joined
May 10, 2001
Messages
889
Likes
0
#7
JP how would I go about testing the coil? (I thought thats what it could be.) Also It is bolted near the rear of the seat under the frame, this is the coil corect? Thanks.
 

JuliusPleaser

Too much of a good thing.
Joined
Nov 22, 2000
Messages
4,392
Likes
0
#8
Follow the wire that's connected to the sparkplug and it will take you to the coil. Check the wire going into the coil for fire. If there is current going in, but none coming out, you probably have a bad coil.
 
Joined
May 10, 2001
Messages
889
Likes
0
#9
Okay, looks like I need a new coil then. Thanks for the help.
 

Jon K.

Subscriber
Joined
Mar 26, 2001
Messages
1,354
Likes
4
#10
If the sparkplug wire comes out of it; then that is the coil.

Again; carefully go through the points setting before replacing any parts.