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Post by johnny3d on Aug 19, 2013 22:42:30 GMT -6
[replyingto=admin]JR[/replyingto]With the kill switch in the "off" or "do not run" position it does nothing. Attempts to start it will not turn the starter motor on or anything else. With the kill switch in the "on" or "run/fun" position, the starter kicks on and it attempts to start the bike as normal.
I'm not sure which I would want to take off and put a teaspoon of gas into. I do know that there is gas going through the carb because I can smell it on the plug and smell/see it just inside the manifold (I think that's what it's called) when I take the carb off the head. I can also smell the gas slightly if I just let it turn over and over.
I did try the "dry" carb trick to get it to turn over... meaning that I took the metal cover off the top of the carb and put a teaspoon of gas down into the carb, put the top back on the carb and attempted to start it and got no fire.
It doesn't seem like I would have fried my CDI to me either since I hadn't even touched the CDI when I was working on the carb and what not. I hadn't disconnected any of the electrical outside of disconnecting/removing the battery. I was very careful not to short the battery or hook it back up wrong when I put it back in.
So far it seems like I am simply not getting spark. I am getting gas and air into the engine, but it simply doesn't ignite. When I've taken the plug out and held it against the block,screws, and even tried holding my finger to the tip I've gotten no spark. The ignition coil does register some resistance. The wires are definitely leading to it are definitely intact (tested with the multimeter), and the CDI's black wire is definitely getting DC power when the key is turned on.
I did notice that there is a yellow cable coming out of the automatic choke that was disconnected and a connection in the wire bundle that looked somewhat crushed. It did not look to me like that had ever been connected. So it's possible that my automatic choke has never worked properly. I did hook up that yellow wire to that connection as it was the only place a connection could hook up there, but I also don't think that is the primary issue here.
I'm going to re-tune the carb air/fuel mixture screw one more time (2.5 turns out) and try and start it again. If it doesn't fire I'm probably going to call this Outdoor Motor Sports place that sells Kymco ATV's and a number of other bikes and see what my options are about bringing it in there.
I've rebuilt carbs for 50cc scooters, taken out and installed a number of 50cc and 80cc scooter engines. Tuned a bunch of 50cc/80cc carbs... swapped jets in carbs... etc. I've worked on car engines and what not... but I'm at a complete loss as to why my scooter will not start. Essentially I'm just shooting in the dark here because EVERYTHING seems like it should just fire up or even fire up and stall or fire up and run rich or run lean or something... but it's just not firing. It just isn't getting a spark for some unknown reason.
Maybe it is a bad CDI? Maybe it's something else... I'm at a complete loss.
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Post by johnny3d on Aug 17, 2013 21:34:11 GMT -6
Well... I went out and tested and found DC current on the black wire leading to the CDI. I also tested the resistance from the black/yellow wire leading to the coil and the green ground wire leading to the coil. Both tested fine. I did notice that on the coil they had the black/yellow wire connected to the 'green' lead on the coil and the green wire connected to the black lead on the coil. That's how it's been set up since I originally got the scooter but it still seems odd.
Turns over perfectly, starter seems strong. Power to the CDI and the wires leading to the ignition coil are all good. The NGK DR8EIX spark plug is brand new.
Spent about two hours fiddling with it, attempting to start it, and fiddling with it some more. Checked the carb again. Re-set all the air intake system back in place again. Adjusted the air/fuel screw to about 1.25 turns out or so. And still it doesn't want to start...
Maybe one of you guys knows a great scooter mechanic/guru in Western South Dakota who can save the day? I know you guys say I can do it myself but I've been tinkering with this problem for 8 days and am losing hope in my ability to fix the issue (even with good advice and help).
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Post by johnny3d on Aug 17, 2013 9:37:48 GMT -6
So far all attempts to track down/fix this issue have failed. I'm beginning to suspect that I need to purchase a new CDI, but I'm not certain about that yet.
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Post by johnny3d on Aug 14, 2013 11:06:59 GMT -6
I tested the ignition coil with a multimeter and its definitely is getting a reading with the Ohm measurement.
On the x10 setting I'm getting a .9 to 1 reading.
Next I figured I would test the wires leading to the ignition coil.
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Post by johnny3d on Aug 12, 2013 18:50:32 GMT -6
I heard it might be a good idea to re-jet it since I'm at about 3500-4000 ft. I've also heard that if I switched from the airbox to a UNI pod filter than it would lean out to where I need it.
I heard from a mechanic guy I called that I can take the ignition coil down to a NAPA and they'll test it for free. So I'll run that down there tomorrow and see if that's functioning or not. If that is functioning that is one less item on the list that I would need to replace to find the culprit in my system. If the ignition coil comes up as being bad, I'll just order a new one of those. I'll eventually figure it out (with a little help from folks like you guys). ;D
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Post by johnny3d on Aug 12, 2013 17:06:46 GMT -6
I was just looking and I can order a new ignition coil and CDI for $31...($40 with shipping costs) which is about how much a new multimeter would cost me.
Thanks for your help so far, by the way... I'm just getting a bit disheartened because what should have been a simple carb adjustment is snowballing into more and more cost.
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Post by johnny3d on Aug 12, 2013 16:17:58 GMT -6
I'm pretty positive that I did not hook the battery back up the wrong way or even short it out. I'm always really careful about that kind of thing.
The gauges come alive, the starter turns, and it sounds like it is trying to start, but no "fire" sound coming from it. I've been hunting around on the web to see if I could find a shop that would take a look/work on it anywhere near me... so far no luck.
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Post by johnny3d on Aug 12, 2013 14:32:39 GMT -6
Well... bought a new plug this afternoon. It wasn't the plug.
I'll end up picking up a multi-meter in the next few days. I had one but it got ruined a bit ago and I hadn't gotten around to replacing it yet. I unscrewed the plug boot and it looked to me like it was getting a decent connection there, but still no spark.
The thing that gets me is that I hadn't done anything in particular with the electrical system aside from disconnecting the battery. All I had done was adjust the carb a bit... So frustrating and it's going to cost me at least another $30 (for the multimeter) just to figure out where it's actually not functioning.
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Post by johnny3d on Aug 11, 2013 16:27:22 GMT -6
I do not have a spare spark plug to try it with. I only have the one plug on hand. I tried pulling that plug and putting it against the valve cover with it in the boot and it produced no spark when I had my wife hit the starter. So if that works, that means I'm not getting power to the spark plug and/or that spark plug is simply dead. I should be able to buy a replacement plug tomorrow either way.
The kill switch is definitely in the "fun" position. When I put it in the "no-fun" position it won't even attempt to turn over the engine.
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Post by johnny3d on Aug 11, 2013 15:57:56 GMT -6
Attempted to clean the current spark plug using some naptha and a bit of cloth to clean up the black soot. It being Sunday, I couldn't get to the store. I tried adjusting the air/fuel mixture screw all the way in (not tight) and then backing it out 1 full turn then 1.25 then 1.5 then 1.75 then 2 full turns out. I took out the spark plug a few times to check and there was definitely gas getting into the chamber, but no telling if it was too much. So far, it hasn't started... All in all I'm starting to lose hope that I'll manage to get it running again.  |
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Post by johnny3d on Aug 10, 2013 22:20:21 GMT -6
Worked on it some more today. Bought an equivalent of the tool you showed up there (the ratcheting offset screwdriver). Mine looks a little different, but it's essentially the same. I took out the spark plug and turned it over for a few seconds, but no gas came out of the hole. The spark plug was pretty black on the tip. It looked just like what a picture of a plug from a rich running engine would look like.
I put the plug back in and tried to start it... no luck. I pulled the air box off, adjusted the air/fuel screw a bit, put the air box back on, and tried to start it again... no luck.
My plan is the following: I'm going to pull the carb out (partially... enough to get at the screw easy but not so much as to need to disconnect everything from it). I'll put the screw all the way in (but not tighten) and then back it out 1.25 turns. I have read that 1.5 turns out is about factory average so 1.25 should give me a little leaner than normal setting to account for the altitude. I'll put the carb back in place. I will also buy a new spark plug. I'm concerned that the one I have in there right now is too fouled up to get a good enough spark to fire. I'm planning on picking up an NGK Iridium DR8EIX spark plug. I'll install that. Then I'll put the airbox back in place and try to fire it up.
I did pull the plug after a couple attempts and I did notice that there was a small amount of gas on the plug and it smelled of fresh gas. The amount on the plug evaporated almost instantly. It didn't seem like an excessive amount of gas to me.
If there is anything else you think I should consider or anything you think I ought to do, please let me know. I have a battery tender installed in the bike and the battery has been kept topped off during this process.
Right about now I'm seriously missing my old 50cc carb... it was so easy to get at that screw. Keeping that one tuned up was so simple. Thanks again for your help and suggestions so far.
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Post by johnny3d on Aug 10, 2013 9:07:30 GMT -6
I assume you mean the spark plug when you say to take the plug out? Not trying to be dense or anything, just want to be sure.
I'll look for one of those tools today. I'm still not certain how I'm going to adjust that screw while it's running even with that tool. The air box blocks most of the access to it. Or do you have some trick to reaching that with the air box still on?
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Post by johnny3d on Aug 9, 2013 21:57:40 GMT -6
Thanks for the reply. I didn't have one of those fancy tools you showed up there. Looks cool though. I loosened the carb and turned it a little so I could turn the screw a bit. I turned it 1/4 turn and then put everything back. When I tried to start it, it tried and tried but no spark, no fire, no start... So I turned it back how it was before and tried to start it again... same result. Currently it's sitting out there charging the battery (I have a battery tender installed in it). I'm at a loss since everything is essentially the same as it was before only now it won't fire up and even run rough.
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Post by johnny3d on Aug 9, 2013 15:47:01 GMT -6
[replyingto=johnny3d]johnny3d[/replyingto]I'm pretty sure I know which is the air/fuel screw...
Since I won't be able to adjust that while it's running, how many turns out should I be setting it for about 3500-4000 ft above sea level?
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Post by johnny3d on Aug 9, 2013 15:12:01 GMT -6
I've just recently moved up into the mountains of South Dakota (about 15 minutes from Sturgis). I've noticed that my Jonway YY250t is idling really rough and that the idle adjustment doesn't seem to be functioning properly. If I turn it down low, it drops the idle down below were it should be (about 1000rpm). If I turn the idle adjustment up, it'll get up to about 1200rpm and instead of continuing to go up it'll start making a 'pop  op op' kind of sound and will jerk a bit. If I crank the idle adjustment screw up all the way it'll idle smoother but too high... I think the problem is that I need to adjust my air/fuel mixture screw, but I'm not 100% sure where it is on my carb. I think I've found it (down out of reach facing down on the back of the air/fuel output side), but if that is it, I can't figure out how to reach it to adjust it while it's running. I made a video so you can hear it somewhat. Hopefully it helps. If there is something else or another video you would need to help me figure this out, please let me know. Here is a video I made quickly so you could hear the problem: Link |
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