Clinician
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Post by kancur on Mar 12, 2018 5:54:50 GMT -6
Some images: ![](https://s14.postimg.org/gs546f9fx/Imag00001.jpg)
Looking at the spark plug now, it seems quite ok to me. Isn't it? ![](https://s14.postimg.org/uykv1ns0t/Imag00002.jpg) ![](https://s14.postimg.org/40qxzxmt9/Imag00003.jpg) ![](https://s14.postimg.org/a1omx0ov1/Imag00004.jpg) ![](https://s14.postimg.org/ultgvhhgt/Imag00005.jpg)
There are some holes there from which air escapes under that. (can be felt when engine is running, and also black soot is visible in there) ![](https://s14.postimg.org/su0i0ldjh/Imag00006.jpg) ![](https://s14.postimg.org/7x49vyadp/Imag00007.jpg)
Yep, the muffler was welded several times, Looks horrible but worked OK (There's a smaller diameter tube inside that weld, it's not blocking the air flow) ![](https://s14.postimg.org/7kcvprcod/Imag00008.jpg) I want to change head gaskets as I have some small amounts of oil leaking there. I also want to change those G circlips for C circlips. The muffler is in really bad condition... But I don't know how I can test if a problem lies there.
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Clinician
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Post by kancur on Mar 8, 2018 10:56:48 GMT -6
Thanks for advice. Why is it so? I changed my piston and piston rings last year, I mostly wanted to gain some experience and it was fun to do. After the job I got an advice about not using G clip - (They said the extra part on G-clip in comparison to C-clip can break off and damage my piston/cylinder). (The original piston came with a C clip but the new one had a G-clip in the package) I definitely don't think it's necessary to open the head and do this stuff, but I must admit I kind of enjoy it ![:)](//storage.proboards.com/3059616/images/ELWck45kIaBpPYtpvDIj.gif) Will post pictures Thanks
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Clinician
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Post by kancur on Mar 7, 2018 11:38:06 GMT -6
I need to slow down for sure. I really mixed a lot of stuff together. Back to the facts: I was on a short ride - and the sound definitely is not the same as before. The sound from the muffler is not the same, it is more popping instead of humming (Sorry really don't know how to describe it in english ![:D](//storage.proboards.com/3059616/images/j7oliHrgM6d9allIZs7k.gif) ). But I noticed the different sound mostly in the first few minutes only. There's no misfiring or anything, the engine runs nicely, but has no power. I took some photos and will upload them probably tomorrow. Anyway, I detached the whole engine from the scooter as I decided I should change some things (head gasket and seals). And put a C clip instead of a G clip on the piston. So I guess I will start from the bottom anyway.
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Clinician
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Post by kancur on Mar 7, 2018 9:16:09 GMT -6
Hi czmdiver!
It has more than 40 000 km (25,000 miles) on it.
If by current top end you mean speed (sorry I'm not a native speaker), it is about 50 kph (30mph).
I'm gonna dive into it right away and will post some pictures.
Yep, the day after that thing with losing power happened, I checked the valves and intake valve had zero lash. I tried to check if valve spring is not broken but I haven't found a problem. I probably made one pretty bad mistake when adjusting the valve when I think about it, I rotated it while I was pushing the spring with my thumbs. So when I adjusted the lash, the valve might not have been seated properly. --- DEFINITELY have to recheck that ASAP.
My exhaust is like 4 times welded. But never caused any visible problem before. Will check that too.
Sorry I don't understand what that means. Can you explain it in some other words please?
About it running different on center stand and without stand at all (in riding position):
It has higher rpm when on idle and on center stand - The wheel doesn't rotate and clutch works well. When I put it on the ground, the rpm drops. This is probably due to the fuel level changing a bit in carburetor.
I serviced the vario last year. And yes clutch is releasing.
Thank you, Will post pictures and updates.
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Clinician
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Post by kancur on Mar 7, 2018 8:29:27 GMT -6
Thanks for the answer. Yes, the oil level is fine. The engine is pretty easy to turn by hand, but it has compression - Seem just about normal. And the problem doesn't seem to get worse when engine heats up - it just works bad all the time now.
Another thing came to my mind. There's a big difference on how the scooter idles on the stand vs. on the ground. Don't know if it means something.
EDIT: Maybe the engine running lean isn't the original problem. Because I tried moving the needle in the carb after that incident but it did not help. Actually, I don't think it was running lean when the problem occured - the needle was in it's upmost position. I actually think it might have been running rich when that "thing" (loss of power) happened when I was doing 90kph.
Anyway, the carburetor is in it's original setting, with original jets, which always worked just fine, and I don't see a reason for it to run lean due to carburetor suddenly. :/
But are there any reasons except carburetor and air leak why engine can run lean or hot?
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Post by kancur on Mar 7, 2018 6:49:20 GMT -6
Hi guys, thank you in advance for your help! My scoot:
Keeway ARN 125 GY6 153qmi - 4 stroke The problem:I was driving WOT at about 90kph (55mph) for about 10 minutes and suddenly the scooter lost power and started decelerating, the engine was still working but I was only able to manage about 40-50kph (25-30mph) after that. Since then, it can not exceed 50 kph (30mph), and having half throttle and WOT doesn't make much (any) difference. The exhaust gasses smell horribly - I suspect lean condition. I don't have a thermometer but engine seems to be much hotter after a short ride than ever. The spark plug shows signs of lean conditions. Engine was also firing into the exhaust on deceleration. It seems to rev just fine on stand. But doesn't have enough power on the street. At first, I adjusted the valves. The intake valve had no valve lash at all. Only effect I noticed was it is not popping or firing into the exhaust anymore, but this might just be a coincidence. The engine idles, but it's pretty rough, but I have long term problems with setting this correctly. The first 0-20 kph seems ok, but then the power diminishes and runs terribly. It does not boggle or anything, the sound is nice, but it just doesn't have the power. Then I checked the carb.Carburetor OK - all jets clean, I changed the diaphragm just to be sure. It definitely seems to be working OK. And anyway, it would be pretty strange if it suddenly "broke down". I can only imagine three ways carburetor can make a problem like mine: 1. Damaged diaphragm (It's not)2. Clogged main jet (It's not)3. Problems with fuel level (This might be it, but I don't see it happening "suddenly". The float level is not adjustable on my carb, and it definitely seems to be OK to me. I would say this is NOT the problem) Air leaks: I checked for air leaks, and found none. I've had problems with air leaks before, but they were mostly present when idling. When the butterfly in the carb opened under WOT, under these low vacuum conditions the vacuum leaks never were a problem. So I'm pretty sure air leaks are not the cause. I recently changed bad CDI for a new one, which worked flawlessly, so I don't really see how this could cause a lean condition or loss of power all of a sudden. My exhaust is in a pretty bad shape and I wouldn't be surprised if there are problems there, but how could it make engine run lean? I don't know. Can engine running lean be caused by something wrong with the engine itself? Like piston rings or something? I'm pretty lost. I'm thinking about opening the engine and checking the piston etc. (I've changed my piston and piston rings before) but it's quite a lot of work and if it's useless, why do it. Feel free to challenge my conclusions. I'm definitely not a pro and might be interpreting the symptoms all bad - maybe it runs rich in the end.. ![:)](//storage.proboards.com/3059616/images/ELWck45kIaBpPYtpvDIj.gif)
Thank you for your help!
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Post by kancur on Jan 31, 2018 5:12:48 GMT -6
I thought about that too. Might be. It's a 10 years old Chinese scooter with 40 000 km (25,000 mi) on it so a lot of stuff is breaking down. But this was the first major hard to resolve problem since I have it. :-) Anyway, if something changes I will report here.
EDIT feb. 2018: Still running great. Must have been the CDI.
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Post by kancur on Jan 30, 2018 12:30:15 GMT -6
So I exchanged the CDI for a new one today, and it works. I have some carburetor problems and difficulty starting, but the scooter works without dying. And I can honk without engine dying. Will see after a week or two if it is resolved by this. ![:)](//storage.proboards.com/3059616/images/ELWck45kIaBpPYtpvDIj.gif) Thanks for all your help!
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Post by kancur on Dec 21, 2017 4:56:45 GMT -6
But I have more than that one problem. The engine dying when honking is just one of them. The worse one is that I can't start. The spark fires only occasionally. Usually the first spark is the brightest and then it fades to non-existent.
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Post by kancur on Dec 20, 2017 10:42:16 GMT -6
It doesn't shut off when the horn is unplugged and I press the horn button. But I will test it all again when new parts arrive and will keep you updated. ![:)](//storage.proboards.com/3059616/images/ELWck45kIaBpPYtpvDIj.gif)
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Post by kancur on Dec 19, 2017 17:24:13 GMT -6
Thank you guys for all your advice, issue is still unresolved and the temperatures outside below freezing so I will probably not work on the scooter during holidays. I ordered new pickup coil and CDI. It will take a while for it to arrive from china. I will let you know once I test it. Thanks
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Post by kancur on Dec 12, 2017 8:47:22 GMT -6
tried a new ignition coil today. No change at all.. might try taking a more thorough look at the pick up coil.
EDIT:
Ok, I plan to do this now.
Wire CDI directly from battery +12V and ground. Ground engine directly to battery.
I've already done this but I will try once more. If it still doesn't work that leaves several options:
Bad CDI - how could I diagnose it? Bad pickup coil or ground or signal from pickup coil.
Connection to the Ignition coil is already made new and should definitely be fine.
I'm pretty lost, but will try to play with it some more and come up with solution.
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Post by kancur on Dec 5, 2017 10:33:51 GMT -6
Ok, I spent the whole day trying to figure out what's wrong. I tried wiring the CDI +12V and Ground directly from the battery. Made no difference. (The scooter miraculously worked fine for an hour during the day when I was working on it, which made me frustrated because I changed all the cables back to original and it still worked. Then it stopped working later during the day.) When it was not in a "running" mood. Wiring +12V ground and even spark output to the COIL directly made no difference. Now it's evening and situation is like this: It usually only fires the first spark. Or first two, but first one is always the brightest. Then during cranking, it occasionally makes a spark. Sometimes it starts - and works for 10 seconds nicely - than dies without warning. That made me think that maybe I have two problems instead of one. Could this be a sign of bad CDI or bad ignition coil (I'm on my second one as my first failed this year with similar things happening - the engine dying randomly.) The strange thing is that it's still not working when wired directly from battery. (When it was miraculously working during the day, it worked with both original connectors or my direct wires to the battery.) This means that the main problem should be between magneto, CDI and ignition coil. I had the magneto cover fan and rotor down today (I forgot to take a photo). I was testing the spark by moving a screwdriver in front of the hall sensor and it worked flawless with strong spark. Then I assembled it and it was working perfectly. Till it stopped working later during the day without any visible reason. Thanks for your help! Here's a photo of my CDI: ![](https://i.imgur.com/gDWERi3.jpg)
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Post by kancur on Dec 4, 2017 8:37:55 GMT -6
Hi guys, thank you a ton for all your answers. It's pretty difficult to work on a scooter right now as I don't have a garage and it's cold and snowing outside ![:)](//storage.proboards.com/3059616/images/ELWck45kIaBpPYtpvDIj.gif) . I thought several times that I found the cause, but it never is the correct one. I tried checking grounds, connectors - but I'm pretty sure I missed a lot of stuff. So definitely have to recheck that. It's hard for me to diagnose because it's sometimes working perfectly and sometimes not. For example the horn trick does not work now - engine won't die when honking. But now it has come to the point when I have this one persistent problem - that might help me find the real cause. It's the starting problem. Engine runs only as long as I hold the starter button (Seems like a ground problem to me). (After trying to start for like 5 minutes or maybe 10, it will suddenly start working without the starter button pressed and works ok, till the next stop, just a minute is enough and starting is problem again. Sometimes it just randomly dies too. ) Another thing is that it starts fine on first try, but I let go the starter button, it dies, and then it doesn't start. I have to wait for about 30 seconds to crank it because it doesn't fire at all. - This might possibly be caused by the spark plug getting soaked in the unburned fuel after the engine died? - If not, then I have no idea what might cause this unwillingness to start without a waiting period of 30 seconds or one minute. I don't have a CDI photo right now. But I am pretty sure it is a DC cdi. I only have one 12v power cable connected to the CDI which gets juice as soon as I turn the ignition key. I even tried wiring it directly to + of the battery to see if there is any power delivery problem. But I only tried it on the stand and it worked most of the time with or withous direct connection so I don't really know. I think you already advised me plenty of useful ideas, so I should definitely recheck all connectors and grounds and I will let you know then. I'm not sure when the weather will allow me to do that. Thank you guys for all your help! :-) Here is a photo of the front where I suspect the problem lies. ![](https://i.imgur.com/p1IKOdl.jpg)
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Post by kancur on Nov 16, 2017 7:59:01 GMT -6
Thank you, I tried to find bad ground without any luck. It seems to work now, and it might have possibly been caused by bad DC connection to the DCI. But I have to make some test rides to see.
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