KymcoForum.com
General => Technical | How To => Topic started by: jmmc on February 26, 2020, 01:03:42 AM
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Not exactly a barn find but an elderly couple bought a Yup 50 in 2002. He died shortly after that. Long story short she needs money and I offered to get it sold. It looks brand new being inside and covered. It only had 130 miles on it. I drained and washed the fuel tank, I put a new fuel filter, and battery in it. Could not get it to run. Took it to a guy who got it running albeit a bit rough. He cleaned the carb and that was about it. He did do some sort of Breather mod in a can shaped filter attached to the air box... I can start it but its starting to run worse. The plug is now black and when I pull the plug I can see black fluid and I suspect its getting waaay to much oil. I got it to run with the air screw out1-1/4 turns but it eventually falls off to were it wont even get to top end.
I'm not a mechanic but I'm handy. I do not know a lot about 2 strokes, I shot to soon and put new tires on it when he said it ran so I have $350 in this thing and was hoping to get $800. now I can only see selling it for some stupid low price for an 18 year old As New scooter. She need what little money I can profit and I need help.
8)
Can I adjust the amount of oil being injected. Sadly I do not even know where the oil pump or meter is? I had a ngk 8 plug and stepped it up to a hotter 7 but that did not help. I really don't want to go the way of pre mix I think that would be a deterrent… maybe I'm looking at that from my age of 64 not 20 something. I need some help Please J.M.
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Someone on here knows. Hang in there for awhile. There are some two-stroke wizards on here.
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bought a Yup 50
This is IMPORTANT: what's a "Yup 50"? You won't get much of a response unless we know that this thing is.
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It looks like Kymco made a yup/sting 50 from 2002 to 2007. I don't know about the oil injection.
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being totally ignorant myself as to what it was when the Widow showed it to me, I simply took the scoot, the paper work, manual etc. put it in my truck and went home. I thought I saw it was manufactured as a model by Kymco from 02 -10. I included a shot of it I searched the net and quickly found a image etc for a 2005 https://bikez.com/motorcycles/kymco_yup_50_2005.php (https://bikez.com/motorcycles/kymco_yup_50_2005.php)
I appreciate any words of wisdom. looks like a well made product.
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It looks like you have a couple of dealers in the area they might have some information. Upstate cycle and Powersports.
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Nice find. These really are pretty simple engines - and all the Kymco horizontal engines are basically the same.
Your plug is probably fouled from flooding - repeatedly trying to start it when there is some problem.
I don't recall what the correct plug is, but replace it. Problem is probably in the fuel system. Properly cleaning the carb and setting the adjustment screws correctly is the place to start.
There is an adjustment for the oil feed. Do you think anyone screwed with the setting? How bad does it smoke?
I wonder if insects/critters may have stored food, or clogged up the intake or exhaust....a clogged exhaust would cause these symptoms.
If you get it running remove that added air thing. It does you no good.
You can probably download a service manual from the 'net. The Yup, Cobra, People, Vitaltity 2T, and Sting from the mid 2000's used the same engine. Super 9 is similar, but liquid cooled.
Around here, there are lots of ads in Craigslist for scooter/moped mechanics offering help. You may find some assistance there if you can't do the work yourself.
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Thank you for your input. I feel like I might be able to resolve this some help.
Correct plug via manual is NGKBR8HSA I dropped one hotter in there a 7 obviously got me no where.
The guy I took it to initially cleaned the carb and being as it would not start initially I'll go with he did it. It would fire with a shot of starting fluid but not stay running.
The breather mod he put in there was in his opinion required. I provided a new air filter for it, but he said it would not draw through it. Being as he has it siliconed in there I'll leave it as one less Varriale to mess with for now. Forgive me if I think a young person might think its a cool thing. 8)
No critters in this thing. there was not so much as a spider web on it just 18 years of dust dirt. It was covered in a clean dry area. All I did was takes some pats off and wash it well
It does not smoke at all once its warmed up and running.
The fuel / air mixture, and resolving how much oil is mixed in is the key as you indicate. It ran "fair" for about 4-5 miles of almost continuous wide open throttle, but it started falling off. as it got around town stop and go. Sketchy in the mid range but not too bad once full throttle full speed was reached. but I would not buy it if I was in the market for one running like that...
I can't really afford more money or I'll have little to give back to the widow lady. I thought maybe $800 if it was running well. I've got $350 in it already.
I'll search for a service manual. Again thanks for the words of assistance…
I'll take any input from guys like you who probably have a ton of knowledge to offer
reality is I can't afford to throw more money atit as I need to get it sold for as much as I can for the widow owner. maybe a tad more butthose two guys would take me to close to whatit mightsell for and I am notconfidentof what that is... is $800 unreasonable for an as new scooter with 150 miles on it... OK its 18 years old... New Tires though! ;D
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I misunderstood your mission. I thought you had purchased the scoot; I see now that you are trying to help sell the scoot.
I don't think that $800 is unreasonable for the scoot in it's present condition. If it ran well, perhaps it could sell for a couple of hundred more. I'd be interested if you were close by - but I know that there was a "scooter scene" in the Greenville area. The two smokes are desirable for enthusiasts.
To check the oil feed - the seat and "pet carrier" lift out with a couple of bolts. Follow the throttle cable - it splits and one cable goes to the carb, and the other to the oil adjustment lever. On the lever there is an indicator pointer that is at a mark on the case when the throttle is closed. As the throttle is opened you will see the indicator move. It should be at the mark when closed if no one has played with it.
I'd still say that the carb is dirty from what you have described. Pretty simple to unbolt, take off the carb cap and remove it. Since it does run a little - after a reclean - put some Seafoam in the fuel and give it a go.
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text'd with a guy who says the following: after sitting all those years the first time I cranked it up the seals in the lower end probably got torn up. equated it to a dry rot rubber band. Says the lower end is loading up. Once it loads up the fuel separates from the oil and the oil is left behind in the lower end and it builds up. The process it takes to move all the fuel is called scavenging, but it cannot scavenge properly because the lower end is not completely sealed. Says it will smooth out eventually as the seals will get somewhat reconditioned via the gas and oil in the lower end. Says I need to ride the heck out of it. several hundred miles...
Today I put a cleaned up plug in it and it started right up. Turned the air/fuel mix screw out 1-1/4 turns. Idles OK. Just sitting there I slowly got to full throttle and held it there. after a few minutes it finally jumped up to got to full revs. I held it wide open for a good 10-15 min. idled back shut it off and pulled the plug. WET... wet sticky oily.
I followed the oil tank hose and it runs though a hose end to and dumps into.... forgive my ignorance... I assume some sort of down stream mixing area/device. there is a linkage to the throttle cable there, so I assume its "metering" it some how?
I ordered a shop manual so maybe that will provide some answers.
What the other mechanic said about the seal gone bad after sitting so long is more than plausible. But if anyone has additional observations I'm open.
As long as that plug is wet and oily its never going to run right.
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Wet plug is your indicator. Running rich.
I didn't want to mention it before, but you should not use starting fluid to attempt to fire a 2 stroke, as the seals may be damaged. However, if the seals were damaged you would be running lean, as air could be introduced into the crankcase. Your seals should be ok. The only way to determine would be to perform a leakdown test, and you are not there. Leakdown test would be indicated if you were lean, and had a seizure.
It completely slipped my mind before, but you need to check the auto-bystart - also known as the "electric choke". They work by having a plunger extend into the carb closing off the enrichment circuit as the device warms up. It "warms up" as the key is turned on; takes a couple of minutes. If the device is faulty, or if the leads are disconnected the carb will run rich. You need to check it's operation.
Here is link to a service manual for the People 50 - it is pretty much the same engine as you have =
http://scootermasters.com/manuals/kymco%20People%2050-complete.pdf (http://scootermasters.com/manuals/kymco%20People%2050-complete.pdf)
Manual shows that A/F screw is one turn out. Adjustments to made when engine is warm.
Good luck.
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Thank you dan V. for hanging with me. Today and on a few prior start ups, I (think) I experienced the auto choke cycle. It starts right away and if I just leave it sit, it slowly ramps up and then backs down automagically... once it falls off I can take the throttle and slowly go to full open and in about a minute or two it will finally get to a full throttle run. not that I know what that is specifically, but its really humming along. Today I did that and obviously it smokes like crazy ramping up but clears out to something reasonable after running a bit. It will run fairly smoothly at this level for as long as I hold it open. I did it yesterday for a good 20+ min and the muffler was so hot it was smoking the tire when I stopped!!! I had to put a piece of sheet metal there until it cooled down. Probably not good.
The down side is... If I shut it off It will not come back up to full throttle. It runs rough and gets about 3/4 of what it was. IF I pulled the plug it would be wet with oil. frustrated I walked away.
I'll check the area you mentioned but did not see that defined in the link
a plunger extend into the carb closing off the enrichment circuit as the device warms up. ??? picture/page
If the device is faulty, or if the leads are disconnected the carb will run rich. You need to check it's operation. Faulty due to sitting or such is a possibility.
I wanted to ride it when it was really humming along but once its shut down... no returning to full throttle. And that's under no load.
J.M.
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OK...so from what you are saying it sounds as if the bystarter (choke) is working as it starts easily, has has fast idle speed, and then slowly idles down in a few minutes.
The Kymco service manuals are pretty poor. I don't recall if they detail how to check the bystarter operation by disconnecting it, powering it, and watch to see if the plunger extends. They mention it, but don't really explain it, and they go into taking a hose and blowing into the carb - which I have never been able to figure out how they want that done. Anyhow, google the procedure - it should come up.
Now the "smoking the tire" thing? You mean the exhaust gets so hot that the rubber was ready to combust?
You didn't have it on the road while this was going on? Did the exhaust to head connection get red hot? What about case in the area of the gears, and the wheel - were they extremely hot?
"I wanted to ride it when it was really humming along but once its shut down... no returning to full throttle" - this is confusing to me. So it appeared to be running well on the stand - "humming along". "Shut down" - you mean returning the throttle to idle, or turning the engine off via key/kill switch? And then it would it then start/idle, and then not rev up?
Have you pulled the carb to clean it again? I still think something is amiss in there.
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I would suggest the problem is the carburetor as well. When I purchased the two 150's in my signature the carb on the Lambretta could be cleaned but the carb on the kymco could not get the smallest passages unplugged and replaced with a cheap Chinese carburetor off ebay.
Not good to let the motor run for extended periods without adequate air flow.
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The general consensus is carburetor so I guess I need to go there. They have always been like voodoo to me. I am very handy... wife says I can fix anything, and generally I can but I hired a guy to go through it because I don't do motors. I saw a few carbs on Ebay and for less that $50. You're saying I can drop something like that in there if I can't make this one right?
So just take it off... take it apart, clean and reassemble... I can do that. I just was always Leary of adjustment screw and jets and such. What do I clean it with? what fluid? I have a compressor... tools in general.
The carb is where air and gas mix, but that oil seems to be the issue. seems like way to much.
Is there any credence to what the guy who cleaned the carb said: lower end is loading up. Once it loads up the fuel separates from the oil and the oil is left behind in the lower end and it builds up. The process it takes to move all the fuel is called scavenging, but it cannot scavenge properly because the lower end is not completely sealed. Says it will smooth out eventually as the seals will get somewhat reconditioned via the gas and oil in the lower end. Says I need to ride the heck out of it. several hundred miles...
So I never sensed anything other that the exhaust as blazing hot. And I know about air flow my bike is a BMW Oil head but needs air so you can't just sit there with it running. Shame on me. Lesson learned. scooters are foreign to me. Learning with your help though.
Thanks Kansas Kymco for jumping in. All I want to do is get it running and sell it for whatever I can get. I'd like to give the widow at least $500. It basically brand new at 18years old... With the manual I ordered, I'm now up to $375. that has me north of $800 which was my target. Praying God places the right person here to fetch a nice scooter for les then 1/2 of new. Deceased husband paid $2195. I have a nice cover an almost new helmet, some tools, and now a service manual...
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OK... totally confident in what is required. Found a decent How To for the same carb and its pretty straightforward. not too complex at all. Sound is bad with the wind, but I get it. I can total get that accomplished. https://www.youtube.com/watch?v=qRN_fDh3LKE (https://www.youtube.com/watch?v=qRN_fDh3LKE)
I suspect it will be clean as I have faith the guy who did clean it, did a good job. Wish I would have come here first but the goal was to get this off MyPlate. Now its not a rush. just get it done...and done right.
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I do not know a lot about the two stroke motors and how the oil is regulated. Just telling you the issues I had with the two scooters I bought that sat for years. If you purchase another carburetor it will have to be of the same design for everything to work correctly. It's possible that even though you had the carburetor cleaned contaminates from the fuel system could have clogged some of the passages again.
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That's a decent video about the carb cleaning. I am surprised that he didn't take the straw from the carb cleaner and put it into the holes to clean the passages after the jets were removed. It will not hurt - blow the carb cleaner into any holes you see.
My Bet and Win had 158 miles on it when I bought it at 14 years old. It didn't run for crap. I found out that whomever "cleaned" the carb before left out the washer and O-ring, and some other little parts (that your carb doesn't have). Don't assume that whomever had done work on the scoot before has done it correctly.....
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You can also just strip the carb as indicated at the video, remove the small metal clip on the carburetor needle, and submerge all carb components except the small needle clip in white vinegar for 24 hours. The white vinegar will dissolve all gunk inside the the channels and after 24 hours you can just use an air compressor to finally blow out the remaining vinegar or possible remaining gunk inside the channels.
We used this method to clean out clogged carburetors at my previous job and it worked perfectly.
Just remember not to submerge the needle clip in vinegar - on certain carbs the metal clips get destroyed within less than 24 hours by vinegar completely.
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quick note. I received my Service Manual and its actually pretty decent. I was worried when I went to some of the Free ones on line with crude drawings and such. This will be a help to me and a plus for whoever gets to own this little beauty. Probably not a lot of 18 year old scooters out there. especially with 150 miles (not Km's) on them.
I have an all day conference Saturday, so It'll probably be next week before I can get back to it. Time changes so a little time after work will help.
Just wanted to stay engaged so you did not think I have given up or such... 8)
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Thanks for the update. Let us know how it goes.
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I'm back.. Saturdays got eaten up. I got brave and removed and dissembled the carb. Its fairly simple as it applies to moving parts etc. I did make a mistake. I went and purchased parts cleaner in an aerosol can instead of Carb cleaner which seemed to be more for cleaning it in place? The cleaner did a good job and I will say that guy I paid to clean the carb obviously did not disassemble it. The jet that has the multiple sets of tiny holes offset from one another in the main jet area was clogged. Took some fine wire and pulled out some green crud. Blew parts cleaner through it from both sides so its clean. My problem was the parts cleaner. The throttle stop screw that has an O-ring … the parts cleaner swelled it and when I was reassembling I pinched it and as I was trying to recover from that in backing it out.
The parts cleaner by this time was eating the plastic handle on my screwdriver so … huge flub on my part.
SO... no idea where to get that O-ring save for finding a store that sells or has a broad selection of sizes, Maybe the scooter store has them? Or..... being as it seems to be a bottomed out insertion I am confident I could Teflon tape that groove for the o-ring to be air tight ???
So aside from that, I think I'll be in a better place with a clean carb. Thoughts on O-Ring?
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Would a dealer or parts supply house have a carburetor rebuild kit for the carburetor with the correct parts?
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Here's a diagram of the carb
Looks like your Oring is not a separate piece and comes with the idle screw.
Try your local ACE Hardware or auto parts store
CJS
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Lowe's hardware drawers.
Stig
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I did some tinkering on two strokes. The oil is either injected, in which case there is a separate oil tank...or it's premixed. If it's premixed you need to find out the correct ratio (shop or owner's manual or try 40/1, using two stroke oil.) The carbs on two strokes are touchy, jets and passageways must be very clean, air box and air filter must be stock, float level must be right on, the air/fuel mixture ratio is critical. If the plug is wet, it's flooding, if dry and black it's getting too much oil. Two strokes show some blue exhaust smoke (oil) even when running correctly. My guess, it's flooding.
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I did some tinkering on two strokes. The oil is either injected, in which case there is a separate oil tank...or it's premixed. If it's premixed you need to find out the correct ratio (shop or owner's manual or try 40/1, using two stroke oil.) The carbs on two strokes are touchy, jets and passageways must be very clean, air box and air filter must be stock, float level must be right on, the air/fuel mixture ratio is critical. If the plug is wet, it's flooding, if dry and black it's getting too much oil. Two strokes show some blue exhaust smoke (oil) even when running correctly. My guess, it's flooding.
If there is a "oil" cap under the seat close to the fuel cap then the scoot mixes it by itself. The more the throttle is open the more oil it mixes with the fuel.
On my wife's Vespa 50 the throttle cable is connected to the oil opening cable (pardon my English), probably the same or similar on most 2 stroke 50ccm machines.
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Hi, here is the carburetor workshop manual for the YUP 50. I hope this will help if you still need it.
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Here is the oil pump set up for the YUP 50