Author Topic: 2-Stroke starts and idles flawlessly, bogs/dies on throttle  (Read 3380 times)

Echo51

  • Newbie
  • *
  • Posts: 2
    • View Profile
Hello! My sis bought one of these for the cheap, it looks miserable, and never quite ran well, but it was somewhat driveable back when she got it. Now it's sat over winter and i wanted it gone out the garage so started fiddling. It starts perfect, cold or hot. Idles well. when you go to rev it, no matter if quick or slow, it will takes revs, to a point, then stop increase revs and sound like it's not running right at all.

I've had the carb off and cleaned, checked the vacuum petcock valve works properly, reset the air screw on the carb, replaced the gas.
New Sparkplug, and checked timing and the coil delivers a spark all while it's running badly.
Had the exhaust off to check it wasn't plugged up but no dice, but i did notice the piston has scratched up and down it's side.
The auto-oiler is also out of order(the lever that the cable pulls on is stuck firm, so it's running pre-mixed gas.
Compression test built up 7-8 bars easily.
Running without airfilter and blocking the intake partly/feeding it starter fluid when trying to run it full throttle doesn't change anything making me think it's ignition or other issue.

Anybody have any ideas? ¨
SHould i be looking at the reed valve/etc for intake leaks? Bad CDI that sh**s the bed once the revs increase?

Update: Air screw fully in, it's able to rev quite better, but not perfect. The Autobystarter/Auto choke seems to be immobile and stuck open = always full choke = too much fuel.
« Last Edit: May 22, 2018, 08:21:48 PM by Echo51 »

mclark999

  • Sr. Member
  • ****
  • Posts: 276
    • View Profile
Re: 2-Stroke starts and idles flawlessly, bogs/dies on throttle
« Reply #1 on: May 23, 2018, 11:55:43 PM »
If the bystarter is stuck on, you should still have good power when it's cold. Once it's warm, it would make it overly rich and run poorly.

From what I've heard, getting the carb good and clean is your answer. You may have to try cleaning it again.

If taking off the airfilter doesn't change the way it's running at all, that's very odd. It should lean it up a lot. 
Denver, Colorado, USA 5,300 Feet Elevation

2007 Kymco People 50 2T
Tecnigas Trek exhaust
OEM variator with 6 gram rollers
OEM 16mm carburetor

Echo51

  • Newbie
  • *
  • Posts: 2
    • View Profile
Re: 2-Stroke starts and idles flawlessly, bogs/dies on throttle
« Reply #2 on: May 24, 2018, 07:04:34 PM »
Hmm, thanks for the input.
I'll give the bystarter a mess about, check it's functioning as intended more in-depth, and give the carb another good-over cleaning.

Air filter on/off changed nothing, neither did covering the intake hole mostly with a finger, just got it soaked in gasoline. :D

An Error Has Occurred!

Call to undefined function split()