KymcoForum.com
Scooters - 125 to 300 => People 250 => Topic started by: escor on May 02, 2017, 07:17:02 PM
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Hello
I am almost 50, do live in Switzerland and I just purchased a kymco people s250 in blue with about 6'000 miles. I am very happy with this scooter.
I changed the spark, the engine oil, the transmission oil. But I am a office clerk "without" mechanical know-how.
The air filter was totaly dirty with black dust: but I had not a new air filter, so I cleaned the air filter with pressured-air. It is now "cleaned" and quite OK.
My problem: the kymco runs still only up to 90 km/h quit normal, but then it takes a long time to get up to 110 km/h. And 110 km/h is the high speed... but it should be 130 km/h on the speedometer. (I have an older foresight 250: an the foresight runs much more faster after 100 km/h).
After my cleaning und maintenance and changing oil, the kymco was only a little bit faster, but still too slow after 90 km/h.
(sorry for my english, I try my best....) :-[
The old spark (which I replaced) was black on the top. So I think, that there is too much fuel?
So I have two questions: :)
What can be the reason for the insufficient top speed?
Can it be the carburetor? How do I adjust more air oder less fuel? I know the idle screw, but where ist the screw to adjust the air-fuel mixture? In which direction I do have to turn the screw?? Does any one have a picture of this screw?
Is there another possible reason for the low top speed? ::)
Maybe I have to adjust the valves? :o
Or can it be the choke (not dismissing 100%?) ? ???
I am glad about every tipp and hint! And I hope, that I will found some help in this huge forum. Thanks a lot! ;)
Wish you a warm spring time an hot summer
Yours, from Switzerland
Edi
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:)
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What a beautiful bike! I would doubt it is the valves but never rule out anything, probably more like the carbs. With no history on the bike it is hard to say, it could be a lot of things overall.
1. Did the bike sit for a period of time?
2. Have the rollers been changed?
3. Was the previous owner a tinkerer type person?
4. Does it feel like it runs out of power, misses, backfires, etc?
Many more questions can be asked but we are shooting in the dark.
With you having no mechanical skills maybe you should find a shop and take it their.
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I agree that it should be able to hit 130 km/h.
If I recall correctly, the screw on the carburetor only adjusts the air/fuel ratio at idle and low speeds. It could be that the carburetor needs to be thoroughly cleaned though.
Definitely replace the air filter. That's a reasonable explanation for a rich mixture.
Valve clearances are something you should check regularly anyways, so if you don't know when they've been checked last I'd recommend doing it. You're also probably due for a new fuel filter.
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Also, not relevant to your problem, but it's also a good idea to replace the brake fluid if it looks dark. It'll absorb moisture from the atmosphere just by sitting.
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Hello
Thank you very much.
1. Did the bike sit for a period of time? It was used very few the last 2 or 3 years. But it was used for small trips on sunday.
2. Have the rollers been changed? No, there is nothing changed (not the rollers where the belt is transmissioned).
3. Was the previous owner a tinkerer type person? No, but very old. The maintenance was made by a kymco dealer at 300km, 3000km, 7000km and 9'000 km (2 years ago). The kymco was used rarely the last two years (the owner got retired).
4. Does it feel like it runs out of power, misses, backfires, etc? Not at all: the scooter goes very good and smooth but strong. The acceleration is great up to 80, 90 and then it's over. I was today on the high way...with wind in the back I did about 105, maybe 110. Against the wind 100.
But changing the fuel filter is a good idea. And of course: I will also change the break liquid: I changed it two times on my honda, so I know how to do. Maybe this change will make the scooter faster ;D ;D
Cleaning the carburator? This is something I have to let do the dealer. But here in Switzerland, the Dealer takes 100 Dollars / hour and I do earn 22 dollars/hour... And If the dealer spends two or three hours, this makes me "poor" :-\
I bought today the new air filter (about 39 dollars...): I will replace the cleaned, old filter tomorow. Maybe there will be an effect.
But it is not very nice to feel no acceleration. I can not overtake a truck safely. With the old 250 foresight (which has 35'000) I can easy overtake a truck that drives 110 or 120.
Thank you very much. I will report you, if I find out something.
Yours
Edi
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Here's a cheaper option for air filters in the future: http://www.ebay.com/itm/HiFlo-Air-Filters-HFA5006-551-5006-/262497090216?hash=item3d1e0bbaa8:g:8AoAAOSwHoFXsDy1&vxp=mtr (http://www.ebay.com/itm/HiFlo-Air-Filters-HFA5006-551-5006-/262497090216?hash=item3d1e0bbaa8:g:8AoAAOSwHoFXsDy1&vxp=mtr)
Or just do a search for HFA5006.
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Hello
I did change today the air filter. I cleaned also the fuel filter with pressured air (seemed to be ok). And I cleaned the variomatic/transmission (there was just dust, but it was quite clean). It was much easier to open the transmission-cover than I thougt.
Then I went on the high way...puh...100, maybe 105 km/h.
I went to an hill and then I got on 120 km/h downhill, not more. But later, on the high way, I had 110 to 115...
So I think, the high speed will come better an better: the scooter just need some highways drives??
But still: compared to my honda 250 or to an Yamaha x-max 250, the people is very slow, no power. Up to 80 it is realy ok, but from 80 on up to 90 the scooter is weak. And from 100 to 110 I can count slowly to 50...
Maybe someone has another idea?
I will try to make some "high-speed"-drives and I hope, that the scooter will get used to it... it seems like if I had to force the scooter to drive faster again.
Thank you
Edi
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Must be a fun place to ride a scooter !
What is your elevation ASL ?
Naturally aspirated engines lose 5% power each 1,000 feet above sea level.
My guess would be your elevation is the reason for about half what you view as a problem.
It's merely a result of circumstances.
The tiny 50cc engines can't hardly get out of their own way at the higher elevations.
Have fun !
redk
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A black spark plug usually means there is too much fuel for the available air. Yep, altitude could be a cause of this. Changing your filter was a good thing to do. It would not hurt to lean out your air/fuel mixture screw some in my opinion. I too am waiting to hear what your altitude is. By the way, that is a beautiful scooter!
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Concerning altitude, I think you're missing the part where the bike is performing unfavorably compared to other 250cc scooters.
If driving the problem away is helping, you could try accelerating matters with some kind of magic fuel additive (seafoam, b12 chemtool, and techron for instance are available in the US anyways).
If you are going to change the idle air/fuel mixture, there's a picture in the manual at 3-6.
You'll need a tachometer and a long flathead screwdriver. I think I recall it fitting through a hole in the frame to the pilot screw.
If I recall correctly, tighter is richer, looser is leaner. First you'll want to find the point where the rpm is the highest. Then find the two points where the rpm drops by having it too lean or rich. Set it in the middle on those points, then turn it 1/8 turn richer.
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From where I sit, lacking all the information, in an ancient thread, ...lol
Adjusting that idle mix isn't going to make much difference.
It will be necessary to pull the carb, at least enough to roll it over and remove the main jet from inside the float bowl.
You will need to work with it, so write down the number stamped on it representing the jet size.
You might begin selecting the replacement main jet by purchasing one that is 4 or 5 digits higher than the existing one. This will lean out the air/fuel mix at higher operating speeds, and down through mid-range. Re-assemble and go for a speed run.
If it spits back out of the intake at high speed, the main jet is now too small. Allow the engine to cool as you motor back to your shop and do not run the engine while it is set up lean. This can be bad for the engine.
Of course it would have been better to purchase 2 or 3 additional jets, when you were at the parts dealer, but it gets kinda pricey, and it's most likely you will never use them again, unless you make a serious change to the exhaust system, or install expensive performance parts within the engine.
Chances are, the dealership may not have jets in the size you require.
There is another option.
First, you must have the tools on hand to do the work.
A decent soldering iron, flux, and solder, and a number drill set with pin vice, in the range necessary... and this goes back to, you must disassemble to find out what is in there, before anything may be done.
If running rich at WOT, you may determine by trial and error, which of your small drill bits is a proper fit for the main jet.
Assure yourself you have the consecutive drills smaller than that size.
Solder the main jet closed, then drill though the solder in a smaller size. Perhaps 4 sizes smaller.
If it shows a lean running condition at WOT, pass the next drill size up, through that solder and run again.
You must retune the idle mix each time you do this, but it will be a quick process, since you should already be reasonably close.
Some main jet needles have a selection of circular grooves near the top where a circlip adjusts the height of the needle, controlling flow from the main jet for mid to high range ratio. A groove closer to the top of the needle will make it leaner, lower down will make it richer.
Better to be a very little bit rich than lean, which builds heat to quickly.
There are also needles with different tapers and they interact with the main jet like a finger in the dike, As the needle within the slide is withdraw upwards, a change in the taper will influence fuel flow.
There are a number of other things to fiddle with, if you are heading towards the winning circle, yet that is beyond the scope here.
it is most likely you will not need to replace your needle or the emulsion tube.
redk
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Hello
Thanks a lot to all and specially to REDK
I do live on about 800 Meters. So there is no problem with high altitude. But when I go up to the mountains, the foresight 250 runs about 60 km/h on 3000 Meters... big difference.
No: the 800 meters are "nothing" to consider.
I will try to run some highway Kilometers and then I try to adjust the carburetor as REDK told me: I hope, I will achieve this.
Thanks
Edi
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I have an '07 S 250, tuned to perfection it's top speed via GPS is 76 on flat ground, calm day. 0-60 will keep most cars off your tail and it will keep up with any 250cc bike I've encountered until that magic 60 at which point they drop a gear a disappear while I creep up to 76.
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Process of elimination, give the carburetor a good cleaning, all jets and passages. make sure the gas tank supplies enough gas.
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I'm getting mixed up with kmh to mph conversions.
This is the run I made after the scoot got back from the shop, freshly tuned, the Kymco mechanic says this is typical of the breed. They also tend to run rich from the factory.
https://youtu.be/zs5wxduQpA0 (https://youtu.be/zs5wxduQpA0)
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that is a good looking scoot
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Hello
Thanks to all :)
I did clean today the carburetor with break cleaner and pressured air as well as I could.
Then I went to the highway. Now the 250 runs up to 68 miles, maybe 70 (about 110 km/h) without problem.
This ok OK and all over much better then before. Smother and stronger.
The acceleration is also better: the kymco runs up to 105 quit direct. After 105 the scooter gets weeker. 110 is now "easy" to go. And after 110 km/h you have to be very patient to get one km/h more. But you can go maybe up to 120...if you are patient on the high way.
I hope, that it will be more better when I do drive more.
By the way: I tried today a new Daelim 250 S3. This scooter runs up to 130 km/h as hell, then the scooter is getting slower up to 145 !!
Of course, the Daelim has injection etc.. And then I tried today (I did visit my dealer...) also an older honda forza 250, this scooter went also up to 125 without Problem.
So: the 250 Kymco is still not very perfect for top speed driving, but I can live with him.
Thanks to all for helping me
Edi
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I ride mine at 60-65mph all day long no problems and I get a kick out of the peole who see a scooter don't expect it to be as quick as it is.
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Hello all
I cleaned the carburetor and the old nozzles with break-cleaner (as I write above). The result was, the kymco runed faster, but not perfect.
I bought yesterday two new nozzles. The big one and the small one in the middle of the carburetor.
Now, the Kymco runs up to 85 miles !
Incredible... :)
So the problem was, that there was a film or covering on the nozzle even if the nozzle looked clean.
Great!!
I am very happy.
Thanks and all the best
Edi
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Thanks for the update Edi! Ride on brother!
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Excellent !
Still, better to relax and enjoy the fun riding. Be observant and take advantage of all that is around you.
Fair WX motorbike riding has Got to be among the best things around !!!
HI-speed WOT runs demand you focus on the immediate situation and so many of the nicer things are missed.
redk
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Hi REDK
You are right!
I do drive slow and enjoy the landscape. But sometimes on the highway there a trucks and then it is good, if you can overtake them fast and quick.
And, of course, in the mountains, you need to have some power.
So it was more: I don't like an car or engine, which does not run like it should. And if I know, that there are 20 miles speed missing, I just "must" detect the reason for the missing top speed.
I prefere to drive safe and spending some more time to arrive, that is for sure.
By the way: the kymco is smooth gliding, the engine is really rolling. The Yamaha X-Max ist more agressive, the engine is more responsive, nervous. The kymco is perfekt to cruise.
Thanks
Edi
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Edi, it would be great if you would post some pics from your travels!
I like pics !!
Seems like you see some interesting things.
redk
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Escor, I understand what you mean by wanting the engine to be working right. I was bothered by this on your behalf, and I'm glad you found the problem.
A 65 mph scooter is fine. An 85mph scooter running 20mph slow is not.
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Here we are....
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and more...
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more
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last
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WoW !
Look at all those hairpin turns !
That must be Great fun !
redk
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Beautiful!
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That 1st pic is Awesome ! I will use it as a screensaver for a while !
...and I would definitely be slowing, to a stop... What a Great view !!!
redk
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What country are these in?
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Have you downloaded the manual (free online)?
Carb removal and clean on a GV250 - body work will be different but the rest is the same. Nice looking scoot. As the others have said there is plenty to investigate. Your English is fine and easy to understand.
In my opinion what matters and what doesn't:
Matters a lot:
Carb - proper cleaning especially the pilot jet.
Spark - ignition (electronic and not too much to go wrong except loose or damaged wires.
Vacuum slide in the carb - if it is working improperly it can kill high speed power.
Jets - must be clean and the pilot jet passage is too small and clogs easily *** the pilot jet provides a ramp to the main jet AND contributes ~15%? at ALL speeds once the main jet opens.
Tampering - because the carb clogs easily with lack of use - one year or more it may have been removed for cleaning before - look a the screws for signs that they have been unscrewed for cleaning. Very likely improper repairs have contributed to your current problems.
Wrong main jet - I experiment with larger main jets. Going too big will actually dramatically reduce power by delivering too much gas - probably not your problem but you should record the numbers stamped on the pilot & main jets.
Matters little
Valve adjustment - never adjusted valves on any motorcycle or scooter and noticed any difference before vs after.
Air filter - it is very large on the Kymco and it would really take alot of miles or dirty conditions before it would impact performance. I do wonder why with only 6,000 miles or km? it appeared very dirty.
Pilot jet idle adjustment - will effect idle and little else. have adjusted it ever which way and so no change except idle - high, low, stall at lights but no effect on the open road or highway.
Spark plug - I have yet to change a spark plug on any 4 cycle engine and see any difference. I'm wondering why your plug was dark / black which indicates a rich (too much fuel) situation.
Idle Screw - before adjusting it. Turn it in 1/2 turn at a time until it lightly seats as it will be damaged by over tightening. Record where it was set at (per the manual)
Kymco Carburetor Remove & Reinstall http://youtu.be/uE3d9QI2m2Y (http://youtu.be/uE3d9QI2m2Y)
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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Thanks for posting those vids, Mrbios!
They are Great !
...I have adjusted valve lash and seen Huge change in performance !
MOF, have one torn down right now because the valves tighten up until it will no longer start properly.
(Tnx for the reminder, gotta get that one running !)
redk
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Your're welcome. It was TONS of work and time to make them.
The only time valves made a huge diff for me was on my 1981 yamaha 650 special. At around 25K one of the exhaust valves stuck and the bike had almost no power and sounded weird. Got it adjusted a local ducati dealer and it ran great until crashed at ~ 36K.
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not sure what's more gorgeous, the mountains or those dead sexy curves carved into them...
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Hello
Thanks to all of you.
The country I do live is Switzerland
https://www.youtube.com/watch?v=p0HGDHN22Gc (https://www.youtube.com/watch?v=p0HGDHN22Gc)
https://www.youtube.com/watch?v=JtGUpydFl-I (https://www.youtube.com/watch?v=JtGUpydFl-I)
I will try to check the carburetor and the spark etc. as soon as possible again: but at the moment I am very pleased with the top speed of my kymco.
Next is to change the front tire. But this is no big problem: I have close to me a farmer, which has the equipment to change all kinds of tires. He takes only 30 dollar to change the tire :) And then I have to adjust the front light, it beams to high. But there is a screw, should be no problem.
Thanks a lot to all of you, thanks a lot for the cool videos!
All the best
Edi