Lag in throttle response

[allanseth23]

Okay ill go straight to the problem. When i twist the throttle it seems that theres a 1 second delay before the engine picks up, cleaned the carb and adjusted the valve clearance the ignition timing is on stock specs and no engine mods. No electrical issue the scooter idles fine. Any help or idea is highly appreciated.

[BettinANDlosing]

The Kymco 250's do that stock. You should get 22g Dr pulley sliders and that goes away. Also the carb is tuned slightly rich for stock so make sure you're air filter is totally clean.

[zombie]

I just posted about the accelerator pump fouling on another thread... Is it a sort of "bog/stumble" or is it just a delay?
Most of these 4t scoots do have a natural delay due to the vacuum diaphragm. A stumble is something different.

[allanseth23]

Before it was hesitation so i thought it was just a dirty carb after cleaning and read mrbios thread, bogging of engine is gone but this i notice some delay in engine response even while on center stand. I checked the accelerator pump and it is working fine.

[zombie]

Can you post up a short video or maybe post up on youtube so we can see/hear what you mean.

It might just be normal... Have you adjusted the idle Mix screw? Good air filter? Good fuel? clean fuel filter? new spark plug? correct spark plug?

Lots of maybe's here.

[BettinANDlosing]

If its the lag I'm thinking of, all of the 250s do that until you tweak it a little. The accelerator pump makes a momentary rich condition.

[zombie]

Could you simply shave off the actuator rod, and eliminate the accel. pump?

[BettinANDlosing]

Not even needed, bending the tab that pushes the plunger just a tad so it squirts less works great. But rather than mean it out like that you can drill a few hours in the air box, up jet just a tad then it'll feel good. Also slightly lighter Dr. Pulley sliders do a good job of getting rid of that lag. My 250 has instant throttle response.

[doublej]

No throttle response lag with my '05 ever.  Rollers now are carbon fiber/graphite 17 gm. with new belt and guides. 

[BettinANDlosing]

Damn 17g is light as hell dude. And that will get rid of the slight lag in throttle on the 250's. Depends on where you live to, if its child it won't be so overly rich when you gas it because of the accelerator pump.

[mrbios]

No throttle response lag with my 2005 GV250 once I cleaned the carb properly.  Before that I had an off idle hesitation.  My setup is 100% stock.

[tanuki]

Hi All,

My new to me 12 days ago '04 GV 250 is now up and running.
Thanks to mrbios for his help, as well as others.

I did the unthinkable Wednesday, embarrassing really. I pulled the carb off to extract the jets, pedaled 8 miles to the motorcycle shop to get new jets, pedaled back and by that time I guess my mind was disconnected from where I had left off earlier because as I grasped the carb I somehow twisted and lifted at the same time and snapped the float in half forgetting that I had left the vulnerable float assembly on the carb without the protection of the float bowl installed...pure dummy maneuver.

The float lay there now in 2 pieces sitting there right before my eyes. What an impatient dummy I thought, now I will have to wait 2 weeks for another one.
Ive made plenty of mistakes in 36 yrs of wrenching on my own bikes but that one made me pause and THINK.

Fast forward to Thursday evening at Columbia Scooters in Portland and low and behold they sold me the only one they had, a used one. Installed and running, Im a lucky guy and grateful to Columbia Scooters that they even considered selling me a used part because a lot of businesses wont.

Had a blast today, ran all over the Portland/Beaverton area for hours on end without so much as the fabled stumble/bog just above 3-4 grand rpm. Upon reaching 4500-5000 rpm it takes off with plenty of power, actually quite impressive to me that this humble 250 rips along like it does. Ive owned literally dozens of motorcycles of all sorts over the years  and few of them had the power to weight ratio this scooter does.
The small wheels will still take some adjusting on my part but I bicycle at least 30 miles per week year round so its not a totally foreign feeling.

Well done Kymco! Oh yeah, almost forgot to mention..I was entranced by the 2013 Downtown 300I on the showroom of the dealership, wow!

[BettinANDlosing]

Hi All,

My new to me 12 days ago '04 GV 250 is now up and running.
Thanks to mrbios for his help, as well as others.

I did the unthinkable Wednesday, embarrassing really. I pulled the carb off to extract the jets, pedaled 8 miles to the motorcycle shop to get new jets, pedaled back and by that time I guess my mind was disconnected from where I had left off earlier because as I grasped the carb I somehow twisted and lifted at the same time and snapped the float in half forgetting that I had left the vulnerable float assembly on the carb without the protection of the float bowl installed...pure dummy maneuver.

The float lay there now in 2 pieces sitting there right before my eyes. What an impatient dummy I thought, now I will have to wait 2 weeks for another one.
Ive made plenty of mistakes in 36 yrs of wrenching on my own bikes but that one made me pause and THINK.

Fast forward to Thursday evening at Columbia Scooters in Portland and low and behold they sold me the only one they had, a used one. Installed and running, Im a lucky guy and grateful to Columbia Scooters that they even considered selling me a used part because a lot of businesses wont.

Had a blast today, ran all over the Portland/Beaverton area for hours on end without so much as the fabled stumble/bog just above 3-4 grand rpm. Upon reaching 4500-5000 rpm it takes off with plenty of power, actually quite impressive to me that this humble 250 rips along like it does. Ive owned literally dozens of motorcycles of all sorts over the years  and few of them had the power to weight ratio this scooter does.
The small wheels will still take some adjusting on my part but I bicycle at least 30 miles per week year round so its not a totally foreign feeling.

Well done Kymco! Oh yeah, almost forgot to mention..I was entranced by the 2013 Downtown 300I on the showroom of the dealership, wow!

How bout a little love on yelp it Google

[allanseth23]

Problem solved! At last throttle lag is now a thing of the past, after relentlessly cleaning the carburetor in my desperation i accidentally turn the carb upside down and saw the needle slide inside the vacuum piston (the needle is supposed to be fixed in there). Put a clip on the needle and some shim to let it sit a bit higher on the main jet.

Also off idle hesitation is gone after re jetting the stock pilot #38 to #45 and main jet #102 to #105

I notice the engine runs smoother with impressive acceleration.

Thanks for all your inputs!

[zombie]

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