Possible To Have Stator Wire In Front (Visible?)

[Pierce1989]

Hey guys, came across a problem. My '81 200 ATC has weak spark, new ignition coil, boot, and CDI didn't fix it. The excitor stator coil measured about 190 Ohms, so I ordered a new one from G&H Discount ATC Supply. It tested 275 Ohms, and I soldered it on like an idiot before checking if it fits, tried to bolt it on, doesn't fit. The connector for power wire is perpendicular with the coil instead of kinda towards the top like the original to clear the metal, and also the plastic on the sides is too bulky to fit mount it. I did notice if I flip it over, with the brackets on the side pointing up instead of down like originally, with the wire connector up towards me, it fits.

Is there any issue mounting it like this? I'd solder on a little wire extension, and make it tight to the top so it doesn't get caught in the flywheel. May have to grind the sides of the metal brackets where the screw goes so it's flush with the circle with this setup. Anyone have this issue with aftermarket stator windings?

Also no returns on electrical, so need to make this work or order another one that would possibly have the same issue!

[Pierce1989]

To follow up incase anyone runs into this same issue, it does work. You can mount the excitor coil with the hole you solder the wire into pointing up towards you. Started trike up like normal in the driveway and it runs the same. Will do some plug chops to see if there's still black sooty plugs with the stock carb as lean as it can go.

[ps2fixer]

Are you sure it's a weak spark vs running rich? The stock exciter coil spec is 245 ohms on your machine which it will never read exact, similar machines spec 100-400 ohms so I'm pretty sure 190 ohms would be usable, but the new one likely puts out more voltage. Also what CDI did you use? Aftermarket solutions generally are generic listings, so hard to know for sure if it's the right timing curve etc, but if it runs the same it sounds to work fine. The pulse generator is the last part not mentioned, but that's more or less just a trigger for when to spark.

To me the black plug sounds to be a rich condition. Get a new NGK/Denso plug and run it for 5-10 mins and plug check it to see what the situation is. You might have to re-jet the carb, never know if someone drilled the jets larger, or put the wrong ones in.

Stock jetting should be #95 for the main jet, jet needle at the 3rd slot, pilot screw 1 7/8 turns out. I don't see a pilot jet mentioned which is strange to me. These specs are based on the 84 ATC200ES manual since the 81-83 ATC200 manual I have isn't the greatest resource.

Also notice under the rich mixture section there is a mention of an air jet, so maybe that's what the pilot jetting is based on (air instead of a fuel jet)



As far as the exciter coil install, the biggest thing is to have the coil part be located right, the wiring/soldering doesn't matter as long as it doesn't short out or interfere with anything else. Same should apply to the ignition coil, it can be mounted any way desired, but the metal mount point needs to have a clean connection to the frame since that's how the coil grounds to make the circuit to the spark plug.

[Pierce1989]

Thanks for the explanation. I bought new CDI, new coil and boots, put them on and didn't see a difference in the size of spark. The CDI was a $20 from G&H Discount ATV Supply. I removed them, put the stock CDI and igniton coil back on, then put that new excitor coil on. Now when I start the trike, it spits some black smoke when revving, and doesn't idle correctly. Which is telling me there was an issue with the spark and this new excitor coil may have fixed it, and now the carb needs new adjusting? Also, when I soldered the wire to the excitor coil, I have it tight over the coil and soldered but the wire is not protected. I put electrical tape around it at first but was concerned it'd come off due to the flywheel moving so quickly and possibly damage something, so I removed it. Hopefully it's okay being bare?

[86125m]

my dad's bike has had the same type of aftermarket exciter coil for 20 years with no problems. are you sure the engine just doesn't need a top end rebuild? what about the carburetor if not clean or not jetted properly it can give you all kinds of problems. This doesn't seem to be an electrical issue it seems to me to be either a carburator or engine problem.

[Pierce1989]

my dad's bike has had the same type of aftermarket exciter coil for 20 years with no problems. are you sure the engine just doesn't need a top end rebuild? what about the carburetor if not clean or not jetted properly it can give you all kinds of problems. This doesn't seem to be an electrical issue it seems to me to be either a carburator or engine problem.

I'm sure it does need a top end rebuild! I don't think either of my '81 ATC 200s have had top end rebuilds by previous owners. I didn't consider this because they always run great, it just bothers me that the spark plugs are black with dry soot after riding for a couple minutes. I just rode it on my street for 3 minutes, using just enough throttle to just putt to test pilot jet, and the plug was black with dry soot. My pilot jet can only be cleaned and not removed. It is the original carb but is the Keihin one with the pressed pilot jet, which I think is somewhat rare (had another post on here about it). What inside the topend do you think could cause it? I thought it was electrical because the gas wasn't being 100% ignited, leaving some residue behind.

[Pierce1989]

Alright, just put new CDI and ignition coil (cleaning contacts beforehand), it has the new excitor coil, and still black soot plugs immediately. Please help! I've thought maybe it's getting more fuel in the combustion chamber than it can burn, even though I checked the float level a few weeks ago when I cleaned the carb trying to diagnose this issue. Could the float or needle cause this, even if the bike is running fine? The valves are adjusted to spec, but could black soot be from the exhaust port not opening entirely? I'm running out of ideas... As a test I have tried rejetting 2 sizes smaller, leaning out the carb needle and pilot screw, and it still has black soot on the plug even as it's starving for fuel by being so lean. Makes no sense...

[ps2fixer]

Yea kind of sounds like a carb issue, maybe someone tried to clean out the pilot jet with a torch tip cleaning set which is basically a super tiny file, or they used a drill bit etc. Hard to really tell for sure since it's such a tiny hole to start with. A set of numbered drill bits could tell you what size the hole is, and find what the stock size of it should be with some internet research.

I know it's not decremented much, but it might be worth while buying a China carb and giving that a shot, generally of what I've seen the are set a bit on the lean side.

Fuel not burning isn't directly a spark issues, too much fuel doesn't burn hot enough, so the soot buildup happens. Same goes if it's too lean, it burns too hot and leaves a leaves a white powder. Very similar to how a wood stove works, too cold of a fire (too lean) creates a creosote build up, having a super hot fire afterwards burns the creosote up and leaves a white powder, care has to be taken though because a chimney fire is possible with too much creosote buildup.

Anyway if you have a nice bright blue/white spark, the ignition system should be fine.

As far as the top end goes, the valves can leak causing low compression, valve seals/guides could be worn and leaking oil into the cylinder (possible cause of the black smoke/buildup), or the rings could be worn or broken making it have low compression and possible oil getting past the rings. Basically to test the top end you'd do a compression test and see if it's in spec. There's also some techniques to tell if low compression is caused from the rings or valves but can go into that later if you have a compression tester or can borrow one.

[Pierce1989]

You're the man ps2fixer, thanks for taking time to give advice. I just did a compression test, 150psi on the dot. Tried a couple times. My manual says 156 +- 14, so it seems like the topend may not be the problem. I actually bought 2 Chinese carbs that didn't fit exactly without modifications and would die going up-hill, so I just removed the bowl gasket and pilot screw/oring/washer and put them on my Keihin. I'll try them out again. Thanks again

[ps2fixer]

Just to make sure, that's 150psi with a warmed up engine right? Also note the service manual says to do full choke and hold the throttle full open. Not saying it's a weird number or anything, just want to make sure the process is right so the number is accurate.

Service manual I have has the same numbers you said, the 84 200es also has the same specs, so yea it sounds like you're engine is healthy compression wise (rings/valves) and also suggests the timing is good.

Good spark, and good compression, so the missing leg is correct amount of fuel.

Also if the needle and seat don't seal to stop the gas flow into the float bowl, it can cause a rich condition too. If you leave the gas on, does the carb ever leak gas? Float level too high would have similar effects, not sure if that carb has an adjustable float level though. I know those 200cc series carbs are a bit strange, I had a couple ATC200X's I got for parts and the single carb that came with them would run fine on one engine, but not the other that had better compression and such. I ended up using a ATC185S carb on the better compression 200x engine and it ran pretty well till it's timing chain broke.

I can't really think of anything else except carb/fuel related on why the plug would be black. I guess it's still possible for the valves to leak oil down their valve guides and still seal well. Does the machine use a noticeable amount of oil at all? A trained nose should be able to tell the difference in the smell of the exhaust for burning oil vs rich on gas (both causes black smoke). Bring it up to Michigan and I'll give it a sniff lol.

[Pierce1989]

Just to make sure, that's 150psi with a warmed up engine right? Also note the service manual says to do full choke and hold the throttle full open. Not saying it's a weird number or anything, just want to make sure the process is right so the number is accurate.

Service manual I have has the same numbers you said, the 84 200es also has the same specs, so yea it sounds like you're engine is healthy compression wise (rings/valves) and also suggests the timing is good.

Good spark, and good compression, so the missing leg is correct amount of fuel.

Also if the needle and seat don't seal to stop the gas flow into the float bowl, it can cause a rich condition too. If you leave the gas on, does the carb ever leak gas? Float level too high would have similar effects, not sure if that carb has an adjustable float level though. I know those 200cc series carbs are a bit strange, I had a couple ATC200X's I got for parts and the single carb that came with them would run fine on one engine, but not the other that had better compression and such. I ended up using a ATC185S carb on the better compression 200x engine and it ran pretty well till it's timing chain broke.

I can't really think of anything else except carb/fuel related on why the plug would be black. I guess it's still possible for the valves to leak oil down their valve guides and still seal well. Does the machine use a noticeable amount of oil at all? A trained nose should be able to tell the difference in the smell of the exhaust for burning oil vs rich on gas (both causes black smoke). Bring it up to Michigan and I'll give it a sniff lol.

Again and again, you are the man. Thanks so much for the help.. I think I was thinking too deep into it. I put on the Chinese carb, set pilot screw out 1.5 turns to begin with, and it cranked up. It needs some tuning, but I tried all ranges of throttle in 2 laps around the cul-de-sac just like the test with the Keihin carb. No black soot at all. That being said, it's too late to bother the neighbors too much so need a longer test but running this same test on Keihin carb gave black soot.

The reasoning behind me disregarding the carb as the problem is because the bike ran great, I have been inside that carb cleaning like crazy, trying different main jets, moving clip on main needle, checking float height...nothing stopped the black sooty plugs. I am thinking either the float was allowing too much fuel, main needle wasn't seating properly, or needle valve wasn't shutting off fuel properly, allowing too much fuel into combustion chamber? I'd love to hear the science behind it. Also, last time I tried this Chinese carb it would run but cutoff uphill or at random times. Possibly just needs tuning.

[ps2fixer]

Yea lack of power under load I'd think it's too lean (typical for Chinese carbs), tuning likely needed but continue your test to see if no more black smoke, and see what a fresh plug looks like with that carb. A wire wheel/brush could be carefully used on the spark plug, the better route is a plug cleaner, which is basically a mini sand blaster, just remember to blow out the plug well before installing to get the sand out if you have one.

Carbs are fairly simple over all, all they do is allow so much fuel to go into the engine with so much air flow. Kind of a metering device. I've built a carb with pvc pipe and some valves for adjusting and made engines run off gas vapor. Hint, it's nothing special like people hype it up to be for MPG etc.

Anyway, the pilot jet is for low rpm. At low rpm the throttle plate/plunger is mostly closed, so there's high vacuum between it and the engine. A small jet is used and the main adjusting screw is for that jet generally. It's basically the low, or idle area tuning of the carb. It makes less effect at high rpm since it's so much smaller than the main jet.

The main jet, which on these Jap engines is generally a needle on the end of the plunger is the mid to high rpm jet. Once it's opening, it allows a larger flow of gas due to the lower vacuum present. The need clip adjuster changes how much the needle valve is open vs the plunger (top end fine tuning), the main jet sometimes has an adjuster, but pretty sure your carb is setup where you'll have to swap jets around to change the tuning. For the needle goove adjustment, the highest closest to the tip groove is most lean setting, while the lowest is more rich.

Needle & seat is the valve on the float in the float bowl, basically it allows or stops fuel from getting in the float bowl so the fuel level is somewhat consistent, which helps keep the tuning accurate. Bridges and stratton engines sometimes have a strange design in this area, and the fuel tank was part of the float bowl system, so a full tank the engine ran slightly rich, and an empty tank the engine ran normal/lean. Nearly every bridges engine I've seen will back fire if you rev it up and let it back to idle when the fuel tank is at say 1/4 full.

Anyway, here's kind of a diagram to visualize the effects things have and different rpms. I know I've seen a better diagram in one of the service manuals for something, but can't seem to find it. It had actual rpm numbers ,and was showing truly the real effect as it was part of a diag manual for whatever machine. Anyway, different carbs have different designs, so this isn't a one size fits all, but it's pretty ok to look at it for a generic sense of what's going on.



Also seems the source talks about a lot of what I just said, I didn't read it but I suspect they go into better detail than what I have.
Source: http://www.iwt.com.au/mikunicarb.htm

Basically that diagram tells us you putting around at say 1/8-1/4 throttle and having a very rich condition is most likely the pilot jet. If you did a similar test by cleaning the plug and getting on the road or where ever and getting in a high gear to use 1/2 throttle would show if the main jet/needle are sized/adjusted right.

Anyway, I'm not a true expert on carbs or anything, but I can apply what I know/understand. Hopefully this gives a little insight on the magic of a carb =).

Oh also should mention, an engine running rich will still run/perform pretty well. It might chug a little and not rev up as quick, but it still runs more or less smooth at static rpms. It can run while being so rich that a situation called washing the cylinders out can happen. Basically under normal operation, there's a thin layer of oil on the cylinder walls that the piston rings ride on to help seal and reduce friction. With too much gas, the gas is a strong cleaning agent for oil, and makes the surface more or less metal to metal, excess heat builds up and can wear out the cylinder wall/piston rings. On a 2 stroke it's not nearly as big of a thing because there's oil in the fuel, but they can have a similar effect on the cylinder walls when running too lean (most of the oil is burned up from the higher temps), and the cylinder walls, piston, and rings can score making those lines on the cylinder walls. It's fairly uncommon for 4 strokes, but still possible. Figured I'd point that out, since a smooth running engine doesn't mean a well running engine. In fact look at any high performance engine like a super charged v8 with a "loppy" cam in it to get the most out of the engine at high rpm. Generally they idle like complete crap, but get in the range they are designed to run well in, and they make massive horsepower. It's hard to find a video of this effect, either it's a cold start and the person is trying to warm it up then kill the vid before letting it idle, or it's on a drag strip with the idle high where it's not doing it (not exactly street cars). This was about the best I could find that was still carb based. Sounds to be well tuned just based on the little blip he gave it. Not really an apples to apples comparison, but just wanted to show an extreme case lol. Throttle response has a lot to do with ignition timing and tuning.

https://www.youtube.com/watch?v=o8k5PwUMUI4

EDIT:

Of course after I post I find a vid right away that shows a more typical example. Olsmobile engines have kind of a loppy cam from the factory and has almost a miss sound to them, completely normal though.

https://www.youtube.com/watch?v=_9EMiPl0WoA

Here's what basically every 350 olds sounded like when I grew up (my dad was a olds fan). My dad put 350/455 olds engines in trucks most of his life.

https://www.youtube.com/watch?v=X9JgRuboAuU

[86125m]

the chinese carbs are touchy some of them work really really well like the ones on my 200x and my 125m. But the one I bought for my 200m never would run correctly.

[ps2fixer]

the chinese carbs are touchy some of them work really really well like the ones on my 200x and my 125m. But the one I bought for my 200m never would run correctly.

I'd be interested what would happen if you took the good working one from the 200x and put it on the 200m. I'd assume it would run well assuming no intake leaks etc since both engines consume about the same amount of air, so fuel tuning should be really close if not the same for both engines. Maybe one carb layout is garbage while the other layout (200x) is good, or are both carbs the same that you used?

Kind of side tracked from the topic, but should be interesting to learn from.

[Pierce1989]

Thanks for all the replies and explanations everyone. Learning from the advice on here and doing it myself saves so much money and adds the experience, so thanks again! So with Ps2fixers advice leading to the carb, it seems like it was the issue. Won't know 100% for sure until I can take it out to the everglades and ride some... the little tests in the cul-de-sac aren't enough. So now the questions are:

1. Should I put the original stator back on with the wire in the back so I don't have a live wire going over the aftermarket stator to the front pointing outwards? If that thing breaks while out in the everglades, that's miles and miles walking back to the truck. Or is it unlikely to break if it's soldered and tight?

2. Offtopic, but can't find answer on google. '81 200 has never had a taillight, or the storage/tool box it mounts under. The 2 wire are hanging off in the back with wire ends on each of them to block water or anything. Bike runs, but headlight is sometimes on, sometimes not. Could these affect it? Should they be soldered together to close that part of the circuit, or is it not affecting anything whatsoever electrical? If not it's probably just a bad connection somewhere. Bout to dig through it, but wondered if this is affecting the circuit in any way?