Carburetor kymco 250 people s and high speed problem, black spark

[TLRam1]

Beautiful!

[Redk]

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

[TLRam1]

What country are these in?

[mrbios]

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 

Carburetor Cleaning Part I   
Carburetor Cleaning Part II   
Carburetor Cleaning Part III   

[Redk]

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

[mrbios]

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.

[RatBob]

not sure what's more gorgeous, the mountains or those dead sexy curves carved into them...

[escor]

Hello

Thanks to all of you.

The country I do live is Switzerland





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