Atc 70, keep loosing spark

[R-tifacts]

My 85 70 keeps loosing spark, it is points ignition and it sits alot between use. I have to pull the flywheel off, sand the points flat with a nail file and then it runs again...for a while then it just shuts down and has no spark. This has happend 4 or 5 times, points were before my time, I know points ignitions were a pain but it seems like I'm missing something. I did put a new set of points in it. My question is why does this happen? and what can be done about it, short of convering to cdi. Do the points burn down as they open and shut???

[tri again]

current runs thru the points when the are closed and they throw spark
or actually throw current to the coil when they OPEN
and that triggers the spark to the plug.
did you put a little grease on the cam that bumps to open the points?

yupp, the first thing I do is superfine sandpaper between the points and then a clkean piece of paper between the points to
wipe out the grit I just created, then they run good until they corrode again.

is the gap good?

is the alignment of the points good?
like do they meet nice and parallel?

I had a honda minitrail 50 that did the same thing and NO fun to
pull the flywheel every time.

I wonder what moderates the current thru the points?
They say condensers either work or not.
Wish I knew.

If I make an absurd suggestion, the REAL 70 folks will jump in to correct me.

Guess everyone is trying to figure how to evacuate the east coast.

[Vealmonkey]

Whenever you file down your points, you should always recheck your gap. Always keep a spare set of points and condenser handy or 2. A little contact cleaner every now and then never hurts. Also don't forget to put a drop of 2 of light machine oil where the points contact the shaft. Also, depending on how old your coil and your spark plug wire may be, they will eventually start to break down and build up resistance as those assemblies heat up. Check your plug condition as well. You may be dealing with several factors besides the points. Best of luck finding the problem.

[R-tifacts]

Good amount of info guys thanks alot, I will look into it and if I find the smoking gun (or two) i will let ya know.:beer Lets say I want to convert to hei, anyone done this? Does the hei 70 quad stator and flywheel bolt right on or is the crank diffrent too?

[tri again]

Most excellent point(s) VM, no pun intended.

I know powered points, like juiced from a battery have current running thru them constantly when closed
which is why leaving the key on is bad, kinda welds the points together if it's not running.

But you'd think the intermittent current thru them from a magneto, they should last forever.

Heck, every car on the road before the 1980's had points.

Points look like they are chromed so cleaning them with sandpaper is said to be a bad idea,
but we all do it because it works.
either to clean off the corrosion but may ruin the chrome plating or whatever it is.

Like you say, higher resistance somewhere else may be causing it too.

(on a car engine hooked to a scope) I DO know that if you pull a plug wire back and make it jump a bigger gap, the
voltage to the plug will darn near double,
from say 40,000 to 80,000 volts
and is a good way to clear a fouled plug.

hmm...now I'm having flasbacks of getting knocked on my &^%$
from plugwire leakage.