KymcoForum.com
Scooters - 50cc => Agility 50 => Topic started by: dirtyd on December 14, 2009, 05:58:18 AM
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i figure I blew it up.
I installed a performance air filter on my agility. Started with 98. After warm up, I gave some gas and scooter revved up and sounded ok. Went down the road to do plug chop and went about 1/2 mile when I felt the engine lose power. Didn't make any noise or die right away, but had noticeable decrease in power. It still revved when given more throttle, but when I turn around to go back it slowed and died. Now it won't start at all. Put everything back, stock airbox and 82 jet that came with derestrict kit.
I get spark on plug, but changed it anyway. Bowl full of gas. Gas coming out of new air filter before I changed it back. When I took off carb to change jet back to 82, I felt for suction at intake manifold and had suction. Lots of gas inside airway in carb.
Everything back stock now and still won't start.
After only now reading wordslinger's post that he has 110 main, I now figure I was way too lean and blew it up. I'm not sure what else it could be. I had to push it back in the dark so I'll double check all connections and try again when the morning comes.
Guess i'll end up doin that 72cc kit anyway.
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You should try a people 50 $1999.00 . Derestricted clutch boss 45-50 mph . Good luck .
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I'm a bit doubtful that you blew the motor after running only 1/2 mile with a potentially lean condition. The difference of 98 and 110 jets is ultimately not much! Assuming that 110 is the proper size jet; it seems that you may blow the motor eventually, but not within 1/2 mile. I could be wrong though! I would start by running back through the carb and making sure everything is working properly. My bet is that it's just something simple! Good luck!
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If you have not installed a big bore kit the a 98 main is probably too rich. Sounds like you flooded you carb and it needs to be drained and let to dry out. I run a 90 main, and alot of people who don't have big bore kits installed run 88 ones. Gas coming out of the filter and in main airway is way flooded.
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You should try a people 50 $1999.00 . Derestricted clutch boss 45-50 mph . Good luck .
I figure If I have the money to get a new one, I'm gonna go with the Super 8 2t. I love how it looks and the 2t should be able to go fast too. Probably same engine as the Super 9, and representative of kymco says it will retail for the same, $1999!
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So I completely rebuilt the carburetor, cleaned it up good, Checked all connections again, even checked valve clearance which I doubted had anything to do with it, but I checked it anyway. Everything is just the way it was when it was stock.
Still not running.
Guess it's going to the shop.
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Are you absolutely certain your getting fuel?
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I have to agree w/ DRmotto. It is most certainly a simple problem, and like shaka said there is not enough time for a lean (slightly) condition to burn a healthy piston! HOWEVER... The first thing to look at is the spark plug. I posted on your other thread a link to an NGK troubleshoot page I will post it again here. Let it all sort of fall to the back of your mind for a day or so, and look at it all FRESH. There is most likely something simple that you over looked. If you want to give up I will pay to UPS the scoot to Fla. Just kidding, but the real is you can find the problem with the help of the people that post here! Patience my brother...............If jpres. reads this he will have another archive of "do not f*ck with it if it ain't broke" !!!!!!!!
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I put my hand over the airfilter side of the carb to check for suction, got suction, and had gass on my hand when i pulled it away. After pushing back to the house i noticed gas dripping out of the air filter, and there was a puddle on top of the engine from dripping off the carb. seems like it was getting fuel. after rebuilding the carb and putting everything back stock, i did same thing and still get gas on my hands. I'm at a loss.
Next it's The Scooter Garages turn to diagnose. I'm gonna drop it off tomorrow.
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Well thanks to Josh at The Scooter Garage, the Agility runs great. Might even picked up a couple of mph. (Still not too fast though!)
There was a carbon deposit that attached itself to the exhaust valve right where it seals. Turns out the 98 was WAY LEAN. The valve itself also had a small lip on the very edge that might have kept it from sealing correctly to begin with, and the amount of stuff he cleaned off the piston head probably got back a cc or so! lol
I'm gonna hold off screwing with jetting and that air filter till I have the money to fix my screw ups again.
Thanks for your help Josh! I really appreciate it.
I guarantee when wordslinger reads this, he'll say, "I told ya so!"
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That's great! I'm glad you got it worked out! Josh seems like a real good guy!
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Thanks for your input guys, I appreciate it!
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Well thanks to Josh at The Scooter Garage, the Agility runs great. Might even picked up a couple of mph. (Still not too fast though!)
There was a carbon deposit that attached itself to the exhaust valve right where it seals. Turns out the 98 was WAY LEAN. The valve itself also had a small lip on the very edge that might have kept it from sealing correctly to begin with, and the amount of stuff he cleaned off the piston head probably got back a cc or so! lol
I'm gonna hold off screwing with jetting and that air filter till I have the money to fix my screw ups again.
Thanks for your help Josh! I really appreciate it.
I guarantee when wordslinger reads this, he'll say, "I told ya so!"
...I run a 90 main, and alot of people who don't have big bore kits installed run 88 ones.
...wow...I was really beginning to doubt what I thought I knew about my carb jetting...Do you know what jet you wound up with??
..I've been fooling around with different jet sizes for a cpl weeks now, and I kept coming back to the 105...
..haven't been on here much, due to all the time i've spent trying to prove that my setup wasn't even close...dang...
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Carbon buildup is a result of a rich condition if it was running lean it would have been light brown if it had any carbon on it at all. I wish I had a Agility to mess with there is something a bit different on the engine that is a mystery. I know flex is running something like a 88 main and has had great success with his 72cc bbk.
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Carbon buildup is a result of a rich condition if it was running lean it would have been light brown if it had any carbon on it at all. I wish I had a Agility to mess with there is something a bit different on the engine that is a mystery. I know flex is running something like a 88 main and has had great success with his 72cc bbk.
..wow..my stock 50cc, derestricted jet was an 85...with the stock airbox...
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While there are formulas to figure jetting, I don't even look at the numbers anymore. If you have two of the SAME scoot, and try to jet them exactly the same, one of them will still need to be tweaked. I ran mine for more than a year with what I thought was a good set up, and have since gone up at least 2 sizes on all three jets. I wouldn't even want to try to figure where the difference is. I just started figuring forget the numbers, and look at the plug/ listen to the engine. What I assume happened to dirtyd was he was running rich all along, until he swapped the air filter. Running slightly lean would heat, and dislodge all that carbon on the dome, and valves. In a way it may have been what stopped him from doing any real damage. Once you get it sorted out a little Sea Foam, or OMC Carbon Guard in every tank will keep the carbon out of your engine, and exhaust. Come to think of it, have you done a compression test? Worn rings would be a suspect for abnormal carbon. Same with valve seals.
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What I assume happened to dirtyd was he was running rich all along, until he swapped the air filter. Running slightly lean would heat, and dislodge all that carbon on the dome, and valves. In a way it may have been what stopped him from doing any real damage.
I believe your are correct as well. The thing is, word says his derestrict jet was 85, and this only had an 82! The stock was 80 in mine, and thinking how scoots are usually jetted lean for emissions when they are new, I wouldn't have thought the 82 would be rich, but more like where I should be.
Thats why I sell a complete kit that will upgrade your scooter and still keep it reliable. I have over 2 years of R&D with this engine and have cases on the shelf with bad bearings after customers upgraded to 82cc kits (purchased from other shops).
I wish I had a Agility to mess with there is something a bit different on the engine that is a mystery.
???
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Which Carb. do you have?
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The Kymco Agility uses the 139QMB 50cc GY6, however if your jetting was lean then there is something I must be missing. That or the shop has its diagnosis wrong. Either way I would like to know more about this problem and Josh hasn't returned my phone call.
Im all about contentious improvement and as most of you know there are a lot of variations from build to build. Maybe Kymco is using a different carburetor than Im familiar with, I doubt it though. Especially since flextrainer's scooter is so very fast with my 72cc bbk and NCY transmission kit. I guess in a way Im second guessing myself when I really shouldn't be.
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Hey guys I've been out for a few days..work. I am still running the same set-up and no hiccups. I do have the kehin carb instead of the kymco carb. The person I got the scoot from had swapped the stock carb for some generic carb and I asked him for the stock carb. I completely went through the stock carb and it ran like crap. I used a kehin off a scoot that had blown up. I haven't touched it in about two weeks and I drive it about 38 miles everyday! It's ready for the second oil change since the rebuild. I change it every 550 miles. 94 main jet is perfect with the needle set one slot from the top (all the way down). That is with head work, exhaust work and intake work.
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I talked to Josh over at the scooter garage and this is what he had to say.
I just copied and pasted our convo, I hope he dosent mind.
Jeremy,
Either the bike was not run long enough for an adequate plug chop, or it was running lean. I couldn't tell you, as I wasn't tuning the bike. I just saw the plug after the fact, and the valve.
The exhaust valve had white deposits and such on it, which is another indication to me that it could have been running lean.
Now, it also had a lot of carbon build up. It's possible that the compression ratio was a bit higher than it was supposed to be due to the excessive carbon deposits. Higher compression ratios require higher octane fuel, and they run hotter. That's another possibility.
I too was surprised that a 98 would not be slobbering rich for that engine. Again though, I am not/was not doing the carb adjustments and such on it... he brought it to me when it broke and he put it back stock. I fixed it and he went on his merry way.
~ Josh
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I talked to Josh over at the scooter garage and this is what he had to say.
I just copied and pasted our convo, I hope he dosent mind.
Jeremy,
Either the bike was not run long enough for an adequate plug chop, or it was running lean. I couldn't tell you, as I wasn't tuning the bike. I just saw the plug after the fact, and the valve.
The exhaust valve had white deposits and such on it, which is another indication to me that it could have been running lean.
Now, it also had a lot of carbon build up. It's possible that the compression ratio was a bit higher than it was supposed to be due to the excessive carbon deposits. Higher compression ratios require higher octane fuel, and they run hotter. That's another possibility.
I too was surprised that a 98 would not be slobbering rich for that engine. Again though, I am not/was not doing the carb adjustments and such on it... he brought it to me when it broke and he put it back stock. I fixed it and he went on his merry way.
~ Josh
..again...I find this interesting...If the good Dr Moto would take a look at my "read a plug" post, and share any observations he might have, I would be very much appreciative...
..i reckon I have a GwangYang carburetor...at least that is what zombie reckons..I have "CK50QT-5" on top of the slider cap...as yet, I haven't been able to cross ref that number...zombie sent me a link...but for whateve reason, I couldn't get it to work...
peace
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Hey slinger, If you copy,and paste the part # on the top of your carb. Put it on google search, and use the "translate this page" option you will find the page I posted. It goes to a KOREAN company ( I first thought Chinese) That makes a replica of the Agility. Your part # goes to their stock carb. Manuf. by them. I am curious about second & third opinions on your plug as well...
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Hey slinger, If you copy,and paste the part # on the top of your carb. Put it on google search, and use the "translate this page" option you will find the page I posted. It goes to a KOREAN company ( I first thought Chinese) That makes a replica of the Agility. Your part # goes to their stock carb. Manuf. by them. I am curious about second & third opinions on your plug as well...
..it just keeps translating over and over and over...
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Try updating your JAVA. That usually fixes pages that reload. Maybe try a different browser if that doesn't get it.
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Try updating your JAVA. That usually fixes pages that reload. Maybe try a different browser if that doesn't get it.
looks like the "CK50QT-5" is actually a model # for my scoot altogether...Not what I have the service manual for...
...I can't get the site to display all the specs...dang....
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...Engine is the CK139QMB-2....
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...Engine is the CK139QMB-2....
Very interesting.
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Some more looking into the Manuf. of your carb is on MY X-Mass list. Maybe the variations in tunning are some sort of "plot" to keep American scooters non competitive! Yeah Right!
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Some more looking into the Manuf. of your carb is on MY X-Mass list. Maybe the variations in tunning are some sort of "plot" to keep American scooters non competitive! Yeah Right!
..I'm having real difficulty with those chinese sites...
..the CK50QT-5 apparently has different piston rings...I've gathered that much at least...