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Putting my bike back together, and I go to start and it’s full throttle when it starts. What is going on?


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Ok I did a lot to the bike it’s been off the road a long time here is what has been done . 
crank seals

electronic Ignition w/ lighting coil 

different head 

new throttle cable with OKO 26 carb . 
it’s a 76’ ty250

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Not to be funny, but, is it a new carb?  If so, is it definitely a genuine OKO?  There's a lot of fakes around that literally don't work.

If the carb is snapping back ok it must be an air leak or something weird going on in the carb with the idle jet or choke.

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I would too look up the gas cable installation and how the idle screw that adjust the slide is set up. 

With new and different carb I adjust the idle screw so that it allows the slide to close completely. 

When the engine fires up I then use the throttle to keep the motor alive while turning the idle screw in until the engine have a steady run. 

I then readjust the screw once again when the engine is warmed up and finally when I have adjusted the the petrol or air screw and the jets. 

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Since you replaced the crank seals, take a good look at them.  Many years ago I had a CT175 that I had split the cases.  I put in new crank seals, put everything back together, started it and it went WOT.  Everything looked good including throttle linkage, etc.  After head scratching I checked the crank seals and discovered the bore was about 1mm too big, allowing air leakage into the crankcase.  This essentially is the same as running WOT.  I replaced the seals, and problem solved.   It's worth a look.

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