coleman CT200u-ex runs ROUGH, cannot start without bike taking off

[lmfaoojose]

First time poster, i apologize if i do not follow correct formatting

today i bought a coleman CT200U-EX from a friend that replaced the carburetor recently and stated that it ran rich and cannot start without the bike taking off uncontrollably. i underestimated this until i started it in his back yard and nearly took down his fence.

im too young to ever have had a car with a carb so i never had the opportunity to mess with one growing up which means i have very limited knowledge on how to tune/adjust said carb. i read that there are two things that are adjustable which are the idle screw and fuel mixture screw, i messed with both but nonetheless i achieved nothing and the bike still pulls forward no matter how hard i plant my feet or hold the brakes.

is there anything else i can do to make the bike run normal?

my problems are
1.bike runs lean
2.shakes uncontrollably upon start
3.takes off upon start, cannot start without holding brake and planting feet.

what i tried:
turning idle screw clockwise (to lower RPMs?)
turning fuel screw counter clockwise (to lower fuel mixture?)

attached are the two things i turned . black is idle screw, brass is fuel mix(supposedly)

 

[toomanytoys]

Stupid question but is the clutch locked up? Causing it to be always engaged.

What makes you think it's running lean?

 

[SAS289]

Ask your friend if he manipulated the throttle linkage in any way that changed the stock linkage arrangement. Ask him if he tried to "bypass" the governor while replacing the carb. Was there any other work done to the engine?

Until you figure this out you may want to remove the chain or get the bike up on blocks or something for safety. If you put it up on blocks make sure the rear tire can spin freely. A freely spinning back tire will also tell you if the clutch is locked up or not.

A lean or rich mixture will not cause a runaway bike on startup. But the throttle on the carb not moving to idle at startup will. Post pictures of your throttle linkage.

 

[lmfaoojose]

Stupid question but is the clutch locked up? Causing it to be always engaged.

What makes you think it's running lean?

now that i think about it i think that could be the issue as to why its all go 24/7, i think that its running lean because that is what i was told i honestly dont know how to diagnose a engine like this ive only ever worked on bmw engines.


also after 5 minutes i tried to turn the choke off and it just dies every time, i have no clue how to fix this haha

i took apart the carburetor completely and reassembled it and it seemed to run a TAD bit better but still sounds like its bogging.

any clues or fixes?

 

[lmfaoojose]

Ask your friend if he manipulated the throttle linkage in any way that changed the stock linkage arrangement. Ask him if he tried to "bypass" the governor while replacing the carb. Was there any other work done to the engine?

Until you figure this out you may want to remove the chain or get the bike up on blocks or something for safety. If you put it up on blocks make sure the rear tire can spin freely. A freely spinning back tire will also tell you if the clutch is locked up or not.

A lean or rich mixture will not cause a runaway bike on startup. But the throttle on the carb not moving to idle at startup will. Post pictures of your throttle linkage.

my friend said verbatim "its stock but i zip tied the governor arm and removed the limiter screw" i did not know this but this surely cant be the problem can it?

the bike also sat for a couple months so the stuck clutch is a feasible explanation for the back wheel always moving.

 

[SAS289]

The "limiter" screw shouldn't be a problem. You should have a look in there and carefully remove the zip tie. Then start the bike with the chain off or up on blocks to see if it will idle.

 

[lmfaoojose]

The "limiter" screw shouldn't be a problem. You should have a look in there and carefully remove the zip tie. Then start the bike with the chain off or up on blocks to see if it will idle.

where would the governor arm be?

 

[SAS289]

In between the gas tank and the top of the blower housing. The pull start and throttle cable may be in the way of you seeing it easily.