pa50 timing/contacts

I seem to be getting a very intermittent spark. it is a new plug. when i remove it and clean it i get a spark. but i got it started at the weekend, ran for a few minutes before dying. when i tried restarting it, i was not getting a spark. took the plug out. which was dry this time, but was a bit darker. still no spark after cleaning it

Any other reason why i wouldn't get a spark?

How robust is the coil/condenser generally. it has been unused in 15 years.

Contacts:

i've set the gap and checked they open at 'fire', question is should they snap open, on my bike the open gradually, (still to check the position of the crank when spark happens). I may need to adjust when the contacts open if my spark is not happening (basically advance or retard the timing) how is this done, i assume the contacts are opened by a cam on the crankshaft, does the contact assembly move on the stator plate?

can the HT lead (cable from coil to plug) be replaced, or is it fixed to the coil

Re: pa50 timing/contacts

You said nothing about a "NEW" spark plug? Buy a new one.

2-strokes are the hardest on spark plugs.

Re: pa50 timing/contacts

The points should not snap open. Then open gradually, over a range of a few degrees.

Re: pa50 timing/contacts

thanks legendre, thats what i wanted to hear.

ed, it is a new plug, as i stated!!!!!!

Re: pa50 timing/contacts

The points backing plate does not move. When you set the point gap, you are actually checking the condition of the cam rubbing block to see if it is worn out or not. The timing is set by adjusting the point gap. You should set the timing with a timing light to get the most accurate setting. You have to make sure that the points are closing. If they do not close the low tension side of the coil will not be energized, thus no spark.

Re: pa50 timing/contacts

How do i advance or retard when the contacts open?

Also, can i replace the high tension wire from the coil?

Is there any way to test the coil/condenser unit?

Re: pa50 timing/contacts

A set of points has two main parts - the fixed contact, and the moving contact. The fixed contact is part of the frame of the points, which is mounted to the stator plate with a screw. The moving contact has a spring, and a block that rubs on the points cam.

If you look very carefully, there should be a little notch in one side of the fixed contact frame. The notch is adjacent to two little pegs, which are part of the stator plate. The notch and the pegs work together as a "pry-point" that lets you open/close the point gap. Slack off the screw a bit (don't take it fully loose, just enough that you can move the fixed contact) and use a screwdriver in the pry point to increase or decrease the gap. Then, retighten the screw.

More gap = advancing the timing, less gap = retarding the timing. A tiny little adjustment can change the timing drastically, so trial and error is the rule. After you've done it a few times, you'll get a feel for how much adjustment is required to change the timing a given amount. It's very sensitive!

Re: pa50 timing/contacts

Try using a timing light as well to check it...works!

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