sup guys sorry I havn't been here in a while (been staying with grandpa after open heart surgery). Ok I know my trike isn't Chinese but it has the common 5 pin harness and the principle ideas of making an engine run are the same. The only real difference between this 30yo trike and any Chinese one cylinder with over head cam is that the pulse module is on my cam instead of wired in with the stator.
I have an '82 atc 185 this thing has been burning a little oil for a while but nothing major. The other day I was out riding it and the chain tensioner snapped so I started liming it back to the truck (about 15 miles) having to put the chain back on every 1/4 to 1/2 mile. When I was about 1/2 mile from the truck the chain jumped off again and I just left the machine idling and popped it back on. When I went to take off the bike went about 15 feet and died like I hit the kill switch. I walked to the truck came back loaded it up and promptly ran outta gas in the truck (oops). So I removed the tank form the machine and poured the gas in my truck.
After I got home I noticed that when the chain came off it cut two wires on my stator (green and yellow) assuming that was the running problem I spent the next day fixing the axel and simply spliced the wires back together. I went to test ride it and it fired on the 3rd pull (usually does when cold) it was running a bit rough and when I gave it throttle it sputtered and died. I figured it was just trash under the needle so I quickly popped the carb off sprayed out the needle and the main jet. It didn't help. Being late in the day I left it over night.
Next afternoon after I got off work I did a good cleaning on the carb to make sure it was 100% clean. The small jet was plugged and it had trash on the air/fuel screw. I cleaned both and made sure all the little passages were clear. Also made sure my float was adjusted right. Again no change in fact now it wouldn't hit at all. I pulled the plug and no fire. Being mad I left it over night.
Today I got up and traced wiring and found I had a broke clip on the ground wire. I repaired it then hit the choke and the bike started on the first pull but ran like crap again I hit the throttle and sputter sputter dead. I said to myself this sounds like a carb problem but im pretty sure I've got the carb clean and set correctly.
I thought ok sometimes the valves can mimic a carb problem so I checked them and sure enough the intake valve was a bit tight. After adjusting the valves I have not been able to get the bike to fire up again not even a cough. So as a last ditch I double checked the valves and they were right I went to my other trike that was running before I submarined it and blew the head gasket. I took that carb (same carb exactly) cleaned it thoroughly and installed it well it didn't help either. So I put in a new plug nothing. I just pull on it till I start smelling gas and call it every four letter word I can think of but I cannot get this thing to make any noise.
Im outta ideas, I mean I have cleaned this carb so many times in the past that I could do it with my eyes closed so im sure it is clean but it hasn't helped, I cleaned and tried another carb I know to be good and didn't help, new plug didn't help, adjusting the valves didn't help. Anybody got any ideas? Just in case you think it may be electrical im gonna post a wiring diagram I drew up (hope it helps)


Im open to any ideas at this point this thing by all rights should have been down at the fishing hole for the past 3 hours yet I cannot get any sign of life out of it other than a weak spark.

 

ok this is the first time I have ever tried drawing one of these so forgive the crappy artwork. Ok this thing is pull start only there has never been a battery on this machine. Keeping that in mind these numbers were gained by me pulling out the plug and jerking the pull start several times in succession but if the bike were running Im sure they would be a bit higher (these things are famous for you needing a flashlight to see if the headlight is on at idle but it gets full bright as you bring the rpms up).

Pin one was reading about 7 volts AC
Pin 5 wouldn't provide a reading as it is a pulse not true ac or dc. but a continuity test from pin 5 to the green wire showed 0.0x resistance (last number bounces from 0 to 3)
Pin 3 showed good ground (after I fixed it)
The green wire off the stator showed about 30 volts DC

Coil
From the wire coming from the cdi to ground showed 0.0x ohms of resistance
ground to plug wire and from wire off the cdi were both open

Also the black wire coming from number 2 is just floating (no its not grounded out) the PO had put in the toggle to kill it as this thing no longer has any electronic controls left on the handle bars. I figured if its working im not gonna fix it til it quits.

Now with these numbers I was getting a weak spark and after fixing the ground it was still weak but better than I have ever seen it and until now I have never had trouble getting this thing to start.

 

I found it. God I hate bad new parts.

Most people when you look at a plug you turn it with the gap up.
Well if I would have looked at it with the gap down I would have noticed the center electrode was loose and fell down and closed the gap. One new, new plug and 3 pulls later and boom it fired right off.

 

whodathunkit?! man i've been studying this case and was trying to come up with an idea. looks like you covered all the bases and i learned something here. i would've never dreamed of a failure like the one you just experienced! what brand was that spark plug?

 

was a champion plug. The very first set of plugs i bought for my first car had one do the same thing but that was 19years ago. Id hate to know how many plugs of whatever brand i have bought over the years.

Oh well i guess it proves the old proverb about in the eyes of a master there is only one solution where in the eyes of a beginner there are many. Im sure you have probably got working on these things down at least as good as i have if not better and neither of us thought "maybe they gave you a bad plug". Im pretty sure if someone with no experience would have been there to say it i would have probibily just have looked at him like he was an idiot. But sure enough they gave me a bad plug. Lesson learned 99.999 percent of plugs that you get are good but if you buy enough the one in a hundred thousand will eventually find you.