Honda ATC70 - No Spark - Coil issue?

[Jackyl71]

So I got a new-to-me 1984 Honda ATC70 off Craig's List that I am working on rebuilding for my 9YO daughter. She's been kind of jealous since i finished the ATC110 that my son rides...

I finished the top-end clean-up and rebuild, finished off with a tune-up kit (new condenser and points) before dropping the motor back in the frame. I took some time to adjust the timing (no pun intended), then added a new coil (Chinese off Amazon), plugged it all in (including a new spark plug), gave the starter a tug while grounding the plug and... NOTHING! No spark, no shock... Just nothing... :wondering

SO I started working backwards:

Plug was fine
No spark from coil wire
Checked the coil resistance values vs. Clymer manual

Primary - 0.8 ohms (Clymer says 0.2-0.3 ohms) *** NOT IN SPEC ***
Secondary - 3.07k ohms (Clymer says 9 to 11 ohms) *** NOT IN SPEC ***

Used test light (6v) connected to Black alternator wire and get good light when pulling starter (I have POWER)


So I have to speculate that the new coil is just plain bad from the get-go, seeing that it looks to be so far out of spec. (This was a somewhat common comment on the reviews on Amazon)

Does anyone else have any experience with this? Should I still get at least a little twinge of spark (or light shock) even with the coil out of spec? Should I just scrap the Chinese coil and pick up another one, maybe from somewhere more domestic? Can anyone post their ATC70 coil resistance values, just as a comparison? Are there any other tests I should run?

And on a somewhat related note: So after installing the new points, I set the point gap by loosening the screw, insert a feeler gauge, then re-tighten the screw. THEN when you have to adjust the timing, you need to loosen THAT SAME SCREW, and readjust the points so they just begin to open as the flywheel comes to the "F" mark, then re-tighten the screw. So why did I set the point gap in the first place if I'm just going to change it to set the timing? Or am I doing it wrong?

And to make setting the timing easier, I was considering sacrificing an extra flywheel, cutting away the extra metal, just leaving the keyed hub and timing marks, leaving full access to the rest of the generator, points, condenser, etc., underneath. Does anyone else think this is a good idea? Or just a waste of a good flywheel?

As always, thanks for reading and your consideration. Any input is helpful!

Jackyl71

[Beau]

i had a very similar issue with my 70.

bought a new coil off ebay.

turns out it was the wrong one. even though it said it would work it wasnt.
had a mechanic tell me the 70 is a 6volt coil and the one i order was a 12 volt i think is what he said. anyways he changed the coil and its worked great.

try changing the coil

[coolpool]

Adjusting the points is the same as adjusting the timing. I believe you're over thinking this. Set it .014 (????...been a while) and start from there. Adjust more or less if you're not happy with the performance. You've picked one of the trickiest motors to set the points on in my opinion. That's why most are shelved with pull starts missing. People get frustrated screwing with them and chuck them in the corner. Once you have it dialled in it should give you many years of good service.

[NeverLift]

Borrow you 110 coil and see if that works.

[jb2wheels]

Tried a different plug yet?

I like the idea of trimming down a flywheel. I've seen it before somewhere. Otherwise PITA to reach in there.

[Jackyl71]

Thanks for all the suggestions. In the end, this is what I did...
I had figured that when I hooked up 6v light bulb to the AC Gen and ground, gave a pull, and the light lit up nice and bright, all was good with the Gen. So I moved to the coil. Tried the new Chinese coil - nothing. Tried the old coil that came with the trike - nothing. Bought another cheap coil from eBay - still nothing. :confused:
So I went back to the beginning...
I used the battery-powered light bulb method for setting the timing the first time I reinstalled the AC Gen after replacing points and condenser. I thought I had it right because it flickered bright/dim at the FIRE line. It wasn't until I watched a this YouTube video (https://www.youtube.com/watch?v=NEQfKv2FTxo) on setting the timing that I noticed how MUCH brighter and dimmer the light should go when hitting the FIRE mark that I went back to the points. They were FAR from set correctly, never closing or even coming close. So I set the rotor at the FIRE position, adjusted the points so they were JUST making contact, then fine tuned the setting using the battery/light bulb. I could really see the difference in the bright/dim now!
I put it all back together and tried powering the light again when I pulled the starter. This time the bulb lit bright and pulsed sharply! HAHA! Progress!
I reconnected the new coil, but still got NOTHING! (DAMN IT!) I connected the other new coil, and got NOTHING! (DAMN IT!) I connected the old, original coil, and SPARK! (YAY!) :w00t:

So my lesson learned was two-fold. 1) If you need to start at the beginning, go all the way to the beginning. And 2) Just because the description on eBay or Amazon says a part is for a 1983 Honda ATC 70 doesn't actually make it so. (#2 also bit me on a replacement throttle cable)

This rebuild certainly not as easy as my ATC110 (smh)

Jackyl71