Agility 50 problems

[yajblackburn]

So I picked up a couple of Agility 50's from the local scooter rental place for dirt cheap.  I work their as a mechanic, but have yet to dig into a four stoke motor.  The bikes wont start, they crank and crank and when they do start up they run for 30 seconds and then shut off.  Like I said before, I'm not particularly familiar with the four stroke motors so I might be missing something here.  I did the usuall, change spark plug, new air filter, new fuel filter, clean carburetor, air screw is 2 1/2 turns out (according to the service manual).  I also checked the gas cap ventalation system but to no success.  If this was a two stroke it would be running by now.....damn four strokes.  I know it's not a compression issue because it does start, it just is so damn hard to get it started.

[Agil]

check the belt for worn, also the cluch, friction area and springs

[Whitewolf]

Hi!yajblackburn.The problem you encounter might be from the fuel level in the carburator.Not enough.This in turn might be caused by a poor fuel flow from the tank or a floater adjustment. Four strokes are better in many ways.You are gone love them as soon as you gone know them. Good luck! Please,let us know the result.

[yajblackburn]

After several months of frustration, and going through the entire fuel/carburetion system.  Someone recently told me to check the valves.  Well I did and they and they was no gap what so ever.  So I adjusted to what the factory (.04).  Well what do you know, it worked.  I never thought this would be the culprit.  It started right up and drove just fine.  Thanks to everyone for their advice.
 

[OldGuy]

Wow, that's freaky! Kinda makes you wonder about the maintenance that's done on rental scooters.   

Anyway, congratulations. 

[yajblackburn]

Yeah, and I am the one that does the maintenance on the bikes!  This is the first two years that they have had 4 stroke Kymco Agility's.  Before that they had 2 stroke Kymco People 50's and Kymco ZX50's.  I'm still pretty uneducated in the 4 stroke area but I'm reading the service manual more and more gaining more knowledge.  Most the rental's I service is cosmetic damage, oil changes and light engine work, nothing that invloves going into the motor itself.  I've heard that the valve's don't usually don't go out of whack, so nobody expected it to be a problem.  It was an easy fix and the bike actually goes faster than the stock 32mph, the bike is in restricted form.  I got it up to 35mph, yeah I know it's only a few mph but you take what you can get right?

[Whitewolf]

    Congratulations! You did it yourself,right on time for the coming season. Unbelivable how out of adjustment they where. I hope you are gone enjoy the 4 strokes from now on.It's the future anyway. All the best.

[OldGuy]

Something else just came to mind. It's probably just as well that it wouldn't run since the valves only cool when they are on the seat. There's very little cooling via the stem. Hope yours aren't burned.