Kymco People S 50 4T Stalls / Unresponsive Throttle

[superkoot]

Hello,
New to this forums (just moved on from all my 80s Sprees) and just purchased a 2007 Kymco S 50 4t (2500 miles) that looks like new. I must start by saying wow on how nice, large and comfy the machine is. The 16 tires and brakes make the old Sprees look like micro machines.


The bike is a bit cold starting but fires once it fires up it does alright. It will ride ok but the throttle response is a bit slow (seems to be better after it is warmed up). After twisting the throttle is hesitates (.5 to 1 sec) then picks up. The bike also had the tendency to stall at red lights when stopped (a bit random and haven't determined a consistant pattern yet). Any ideas?

The bike also seems to be a bit sluggish up long hills (seems to drop to about 18-22 mph) and goes about 35 on flat ground. Is this typical or are there any built in restrictions like the old people 50s? Do the performance parts for the people also work for the s 50 4t?


Thanks for all the help and I'm excited to be a part of the kymco forums. The bike is a beauty and it is the best 50cc two seater I've ever ridden! Thanks again for the help

[Shaka]

Sounds like you might need to adjust your mix screw on your carb to cure the hesitation.

[zombie]

Shaka got the first question, and to answer the second...YES the scoot is restricted, some after market parts will interchange,and I would recomend making a plan before purchasing parts. search other posts w/ your model scoot (especially the de-restrict) There is alot of info on this forum that will help you avoid the tunning pitfalls. If you do your mods right you will wind up w/ a reliable machine-If not you will regret spending the money on the wrong parts in the wrong places. Look through, and post back. People here are quite friendly, and helpfull

[superkoot]

Wow, I'm surprised how easy that was. It was almost too simple. I made the adjustment and the stalling and hesitation are gone. I looked in the service manual and it gives the air screw adjustment as:

BA10AB.AC.50 : 1* +/- omega turns

I've never seen this notation. What exactly does it mean?

My scoot seemed to run best with the screw out 2 1/2 turns (seems like a lot compared to the other scoots). Does this seem right?

Also, the spark plug was all white on the tip? (Lean?) Should it be replaced or will a good cleaning do?

Thanks again!

[Shaka]

I'm not sure what that notation means.    Glad you solved the problem though!  I'm running 2 1/2 turns out on mine also, however it is an Arreche carb.  I don't think that sounds unusual, better rich than lean though!  You could probably get away with just cleaning the plug, but may as well replace it. 

[superkoot]

Quick update:

Bike had been running alright in the afternoons (~65 degrees) (thought problem was solved), however it seems to still struggle in the mornings (~45 degrees). In the mornings super slow throttle response and seems to want to quit when stopped on an uphill or downhill.

The air/fuel screw adjustment has helped the stalling but still a bit erratic when idling in cold temps. I'm planning to clean the carb and check the valves (doesn't anyone know the correct valve measurements?) this weekend. Hopefully this will help.

Anyone have other suggestions? Similar problems?

Thanks again for the feedback!

[zombie]

This link is the wrong page, but it will get you to your manual

[zombie]

Forgot to post the link!pdftown.com/PDF-Kymco-Vitality-50-2T-4T-Service-Manual.html