KymcoForum.com
Scooters - 125 to 300 => People 250 => Topic started by: ifican on March 16, 2014, 12:40:58 AM
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The sounds and loss of power i have read others have but not really the same problem. When cold scooter runs up to 85 no issues. When warm however only gets to 70ish and goes no more, when this occurs it also makes a strange internal fluttering sound. Sounds like the muffler is partially clogged. Acts 100% normal all other times and speeds. Warm from dead stop, acceleration spot on, any other speed or other condition fine. Only at highway speeds once warm does it make that sound and it makes it every time. As soon as speed drops or let off throttle sound goes away. Get on the throttle again and right about 70 right back. Picked up with 4600 miles on it, has 15.5k as of today. Belt has about 4k on it, has new plug, ignition coil and fresh oil (both). I have heard rumblings of cdi but agree as most cdi's arnt usually intermittent they either work or dont. Though i have had ecms on cars act funky when hot. Looking for input as its driving me crazy, stay 65mph or less and it runs like a champ. Only issue with that is 65 mph around here and youll get run over.
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Ok changed title because i am a little closer, figured if i waited long enough something would happen. Well new symptom, Pretty much from the time i start up when i go to accelerate (roll throttle alittle or all the way), will slowly accelerate for 12mph or so then it takes off. I am really leaning towards fuel so i put in a nice quantity of seafoam yesterday and we will see how that goes over the next half a tank or so. It did do one really weird thing. yesterday after acceleration to highway speed hit a pocket of traffic slowed to 25-30 while splitting lanes. When traffic opened back up would only do about 50mph wouldnt go, same feeling as from my previous post but just no faster. Pulled of freeway put on stand, gassed on it, turned off and back on no luck. Still supper bogged down and wouldnt go. While limping back home, started same behavior as no oomph from start then takes off about 15mph.
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Check your vacuum lines on the carb and the diaphragm on the top of the carb for holes or tears. Sounds like its not opening up the carb all the way and your air fuel ratio is off.
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sorry about delay work has been killing me. Havent gotten around to checking yet but symptoms are becoming more regular and hopefully more telling. What its now doing is most of the time slowly accelerating to around 20 then going strong but more and more will only slowly accelerate to 40ish and go now more, just no real power. If going up really step hill will go up it but never exceeding 10 mph. On way home from work tonight, 75 on highway whole way then once got off highway (slow for offramp exit) would never get above about 40. Its about 1.5 miles from exit to home with several stop signs. No real power, acts like it wants to go but nada. Hopefully will get some time in next few days to dig into it some but otherwise looking for ideas.
one other thing, put on stand when got home and let idle a bit. Lightly opened and closed throttle but rpms stayed up and spun rear tire, higher rpm then fast idle when its cold.
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+1 for Punk's post. Ethanol in fuel swells the rubber diaphragm untill it does not respond to throttle.
Just to eliminate one big issue I would do a compression test, and a vacuum test. If you need help w/ these just ask.
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compression is good, may be down alittle from age but i have owned plenty of bikes in my time that had compression issues and this is not one of them. I will definitely look into vacuum and carb issues. Hopefully will get a chance within the next week to look, will post once i get a chance to look and see what i find. Thx for the input......
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You're welcome. Most often you will find it yourself but throwing ideas out there helps.
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A few things you've written bring to mind some things I've been going through:
Muffler noise - My muffler has about 20,000 km on it, and is making some noises. Normal running, it sounds normal at this point. Back off the throttle, and there's some minor popping. And when riding around 60 mph and greater, I get a sound out of it best described as the jangles of a tambourine fluttering. (Helps to be wearing an open-ear helmet or no helmet to hear it.) I think it is an internal baffle that has let loose. I will eventually be replacing my muffler. (They are not repairable from a practical standpoint.)
Some of those speed issues you mentioned make me wonder if you have some carburetor jets plugged, although your scenario is not quite the same as mine. Especially the constant changing of max speed and power.
I had lost about 10 mph off of max speed; I took it to a shop and the guy found a wet and oily air filter from blow-back. Replaced that. He also found a few vacuum hose leaks. Fixed that and put it together for a test ride. After that, it was worse! Very slow acceleration, and top speed only about 44 mph. Next, he pulled the carb completely and found plugged jets. (I believe he may have used an ultrasonic cleaner? Don't remember.) After cleaning the carb, I had my original top speed as I recorded when the bike was new (73 mph gps.) Acceleration was way better too.
One last word on fuel conditioners: For about 5 years I was living overseas, and my People 250 was kept in storage here. I rode it for a week or two, twice a year when I came back for visits. I had used Sea Foam for a time, but tried a product called "Sentry" after a while. Definitely had an easier time starting it the first time out of storage with Sentry than I did with Sea Foam.
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Appreciate the insight, the top end returned and part of the noise went away with 2 full tanks of heavily juiced seaform. I didnt measure but would speculate was between 5-6oz each tank. First tank it idles rough most of the tank, second tank was much better. Somewhere towards the end of the first tank i realized it was helping. So needless to say i am sure it was gunked carbs, but where we differ is i put about 150 miles a week on it and it has never sat more then 3 weeks and thats not that often.
As for the other part of the noise i discovered the rubber grommets on the heat shield thats screwed to the muffles has rubbed to nothing, so the tambourine sounds for me are from that. It only seems to do it at certain speeds and or wind conditions, that one took a little while to figure out.
My only real issue is i am a bit lazy when it comes to dealing with this stuff, my free time is much more valuable to me so i would rather drop it off to someone and let them deal with it. Problem around that is we dont have many shops around that work on scooters and the one thats the best known i will never deal with again. So i have made my own bed in that regard. As to air filter it was a bit dirty but otherwise doing what an air filter is suppose to do, no other evidence for me of any issues there. When the carb was taken apart was anything changed / dealt with (float) or just cleaned. I was really hoping it would fix itself with cleaner as i really didnt want to tear apart but appears i will need to after all.
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This is making me think of what we call "stacking". It's when you have enough "micro" debris in the float bowl or fuel filter to get sucked into a stack, and block off fuel flow until the engine is shut down, and that stacked up debris settles out. It can happen over, and over, and over.
Sometimes conditioners will help by dissolving some organic particles but mainly the solution is disassembly, and thorough cleaning right down to the fuel lines. In fact for the cost of a couple feet of fuel line is may be best to clean/replace everything from tank to carb.
Inside the fuel tank, and on top of the petcock is a stainless steel micro mesh screen that also should be removed, and washed out w/ Carb Cleaner. The gasket on the petcock/tank is pretty stout so no worries about needing a replacement for that. Those screens are so fine that even sludge from water ( it's in ALL fuel) can block the flow. for an '07 model i'd say it's due for a "makeover".
Maybe some of this will help, and for sure it couldn't hurt
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All great points and completely what it feels like, though last ride it got stuck at one point at only 50mph now that its been sitting a couple days i bet i would go hwy again no problem. And you can be damn sure i will replace the lines i can easily get to because i hate having to go back a second time for something that should have been done the first.
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Keep us posted.
I just posted on a thread with similar symptoms, and it is still on going. The fella w/ the toasty valve.
Lots of similarities between the two posts... I wonder if they have a common denominator??
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Dont feel like searching so am going to take the lazy route and post here. The symptoms initially made me suspect tight valves. So i took it to local guy and had him adjust. Exhaust was spot on but intake were rather tight. Didnt fix the problem but definitely was contributing as the bike would work less and less well as it got hot, cant hurt might help. I was about 7k on last adjustment. I dont remember what kymco calls for but i think it is 4k check if i remember right. So if he has not done them in a while or does not know last time its worth checking.
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Ok time for more input. Pulled the carb and one of the jets was a little gummed but all good now. Spark checkedt out good, compression may be suspect but i need to find more numbers. it would start out about 90 and go to 120 after 5 or 6 cranks. The interesting piece is while fooling with it seemed to have a small air leak around the intake boot side of the carb. As a test wrapped a little electrical tap around carb side remounted and it still seems to have a little leak. Cant tell if its the throttle arm or intake boot. Boot looks crack free but who knows. Local mechanic i was chatting with says change the carb. Remember when this first started bike would only do about 35, though maybe emissions screwing with stuff. so plugged off emissions and seems to go back too starts really slow till 30 or so then takes off again. But it has been exhibiting that behavior previously so not sure if its random or emissions. Either way still not fixed. Input on any of the above?
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Compression will build on each stroke. BUT if there is a valve leak it will build slower. Usually 3 cranks gets it up to top psi.
A gummed up jet means lean, and lean burns valves. What color is your sparkplug tip? Look inside the ceramic part too It should be like a coffee color. Any white/tan/fuzzy appearance is not good.
Those rubber boots fail ALL the time. What makes you think it is was leaking? Usually they crack, and it is easy to find if you flex them around.
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Check your carb diaphragm open the access cover in the met in box and carefully remove the two screws holding the cap on top of the carb remove the cap and long return spring then carefully lift the diaphragm unit out look closely and see if there are any holes or tears evident the replacement is very simple and inside the canister there is what looks to be a plastic screw slightly depress this while turning 1/6 turn and it will unlock the cam releasing the diaphragm from the body be careful not to drop either the little spring or needle to put it together again with new diaphragm use small pair of needle nose to hold screw upright holding canister upside down by needle lower canister over the screw spring assy and when in place either turn slightly to start cam or carefully turn over and use screwdriver to set cam that's all install into carb body carefully setting top into rib and add cover.
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Someone previously said to check diaphragm as well, plan too just havent gotten around to it. As for the leak right after put back together was spraying carb cleaner while engine was idling around boot and throttle arm and idle would choke as gasp. Was a fluke actually finding it cause didnt think to check. Would do it almost every time. Though i was chatting with my neighbor trying to get it to do it again this evening and could not so who knows. Ill try to get at the diaphragm when i get a chance, but honestly probably not going to be for a good week. To many higher priority things going on right now. But we will see.....
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??? What could possibly be more important than your Kymco Scooter?
I'm a doctor, not a ______ ! Go McCoy! (http://www.youtube.com/watch?v=bVhcB9ucmdg#)
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It sounds like your scoot has multiple problems. CDI - no. Valves - no. Ethanol gas - no, I run Costco gas all the time with no issues.
Carburetor - Yes, multiple issues.
The high idle is a sign of a vacuum leak. When the boots on the carb are tightened enough you shouldn't be able to move the carb. If you can move the carb because it is slipping in the boots then the clamp needs to be tightened.
Off idle hesitation - pilot jet & pilot circuit is clogged. You can clean the pilot jet but you must also clean the passage that the gas travels through before it gets to the carb. Unlike the main jet which delivers gas directly into the air stream. Another sign is things ran good while cold - the electric choke will mask the lack of fuel at low speed until the scooter warms up and the electric choke stops delivering extra fuel.
Top speed issues:
Probably the vacuum piston / vacuum slide - the big rubber diaphragm is leaking or not sealed properly. If it leaks even a tiny bit top speed is limited to about 45mph.
Muffler - possible leak. If you get a leak and loose back pressure you will very quickly loose lots of power. Rattles are a result of poor welding of the internal baffle that I call the Hot Dog in many of Kymco's mufflers made in a certain time period. I had to open my exhaust and remove the loose part and weld it shut so did another guy on the forum from (Romania?).
Consider watching my carb videos for more info on the pilot jet cleaning.
Carburetor Cleaning Part I http://youtu.be/w4vW4zh8g0Q (http://youtu.be/w4vW4zh8g0Q)
Carburetor Cleaning Part II http://youtu.be/ig0qHhdxJFE (http://youtu.be/ig0qHhdxJFE)
Carburetor Cleaning Part III http://youtu.be/EjCmiZ5xoeU (http://youtu.be/EjCmiZ5xoeU)
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Great videos thx, the diaphragm looks good. Pulled it inspected and put back, seemed that there was alot of play in the throtte needle but been so long since i had a carb partially apart i forget. Put back together and no real change in how it runs. Next task i think is going to be pulling the carb completely and going over it all. As in the video whats the easiest way to clean the pilot fuel passage. Also does anyone have a surfire way to test or tell if its fuel or spark. Feels and acts like fuel but i have seen spark in the past cause weird issues as well..
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Clogged idle circuit or non functional choke. Just my guesses.
Automatic Enricher Operation (10x Speed) : Choke Bypass Bystarter (http://www.youtube.com/watch?v=O2qRVOkfdaY#ws)
A can of Carb clean will blow out the passage, and these help clean all the tiny ports...
http://www.homedepot.com/p/Lincoln-Electric-Oxygen-Acetylene-Torch-Tip-Cleaner-Kit-KH575/100341101 (http://www.homedepot.com/p/Lincoln-Electric-Oxygen-Acetylene-Torch-Tip-Cleaner-Kit-KH575/100341101)
Have you tried adjusting the idle mix screw? You should be able to stall the bike with it if it is working.
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Clogged idle circuit or non functional choke. Just my guesses.
Interesting video. At first I thought nothing was happening..
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Ok finally got some time so just now pull the carb completely out and basically stripped it. Sprayed a little cleaner in all ports and made sure it was minimally dripping out somewhere. Put it all back together and it runs much better. I need to take it on a few longer rides and a few highway jaunts but it seems much better already. I still think there may be a minor vacuum leak somewhere and the carb may need a good soaking as prelimary minor clean seems to have made a difference. More to come in the next couple weeks as i get some time put on it and we see how it behaves.
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... prelimary minor clean seems to have made a difference. More to come in the next couple weeks as i get some time put on it and we see how it behaves.
I just updated the video links. I used the technique in Carb Cleaning Part III where the plug is drilled to access the pilot jet passage. The Keihin Carb uses the tinyest passage I have ever seen. I recommend increasing the pilot jet to #48. You wont believe the difference it makes and mpg is the same.
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;D ;D
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Ok more good times. Pilot jet and fuel passages seem clean. Looked over carb again today, perhaps the light was better than before but found a small tear in the diaphragm that i did not see earlier. I have a hard time believing that tiny tear could be causing all the erratic behavior but we will see. Will update once i get part in and get it changed out.
A question why i am at it. While searching around i cannot find just the diaphragm. Only part 16019 which seems to be the vacuum piston and diaphragm together. Is that common?
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Whatever mm the carb bore measures. my guess... 32mm ish. Order a whole new carb fo like 50 bucks
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Actually thought about this and as i was looking couldnt find an exact match. The oem carb is close to 250 with shipping and lots of others that look like they would work in the 150-185 range with a couple right about 80 that i could probably make work but would take some tinkering at least from the pic.
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It's a 30mm CVK Carb. There are a couple here... http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.X30mm+cvk+carb&_nkw=30mm+cvk+carb&_sacat=0&_from=R40 (http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.X30mm+cvk+carb&_nkw=30mm+cvk+carb&_sacat=0&_from=R40)
All you really have to do is swap out you jets into the new carb.
This place has the diaphragm but it is 37.50 by itself... http://www.kymcopartsmonster.com/p/Kymco-Parts#/Kymco_USA/BA50AB_People_S_250/Carburetor/2K03080005/2K03080031 (http://www.kymcopartsmonster.com/p/Kymco-Parts#/Kymco_USA/BA50AB_People_S_250/Carburetor/2K03080005/2K03080031)
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Thanks for this, i had already ordered the part i needed, if that does not work i will be looking back at these. Either way will advise for anyone following one way or the other.
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Cool Beans. Keep us posted for sure. ;)
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so i think this one is licked. It makes total sense but i still cant believe a hairline crack in the diaphragm caused all the chasing it did. Its so close to the edge and sits together so nice in general that i missed it the first time i took the carb apart. I only did a 6 or 7 mile test run more testing to go but it ran like new for the first time in about 8 months. All the previous reported problems gone. The other interesting thing was i actually have to turn down the idle. Thanks all for your input and insight.
So there is no confusion that is a stick pin i set inside the tear to keep it slightly open.
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Yep I thought so the people diaphragm moves much more and in turn folds itself more often and so cracks... just plan on replacing it every 12- 15000 miles it's simple and cheap enough just a pain. Enjoy the ride I wish mine were still ride-able. Damn Elk....
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... a hairline crack in the diaphragm caused all the chasing it did. Its so close to the edge and sits together so nice in general that i missed it the first time...
Thanks for the photo and update.