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Discussion Starter · #1 ·
i have an 04 Sportsman 700 (carb model) that will idle all day long but when given throttle it will only go to 1200rpm (if I'm lucky) and takes a while to get there. hold it wide open and it will slowly work its way to 1200. The air fuel screw is set to 2.5 turns out, needle is on the 3rd clip, everything's clean (brand new carb). now the slide doesn't appear to be moving at all, i took it apart and cleaned it and lifted it by hand it feels smooth but it wont move when I use the throttle. also, after about 5 minutes of running (I do have a fan blowing onto the radiator for cooling) the header pipe is glowing red (the Y pipe at the head of the engine). If I hold the throttle wide open and lift the slide by hand, it shoots a flame and dies. all the electronics check out, all fuses check out, the exhaust is clear. I don't know what to chase down or do next, I've exhausted all the options that I know to do. Any help or guidance is appreciated
 

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It was a Chinese carb, you don't even have to ask

Make you a deal - I will pay for your Chinese carb and pay the postage if you will send me the Mikuni carb you removed.
 

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Discussion Starter · #4 ·
does the same thing with the Mikuni carb. someone stripped the threads in the fuel/air screw hole. Jets were taken out of the mikuni carb and put into the chinese carb and still have the same results
 

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does the same thing with the Mikuni carb. someone stripped the threads in the fuel/air screw hole. Jets were taken out of the mikuni carb and put into the chinese carb and still have the same results
then have something other then the carb going on with it if it did the same thing
 

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does the same thing with the Mikuni carb. someone stripped the threads in the fuel/air screw hole. Jets were taken out of the mikuni carb and put into the chinese carb and still have the same results
The Mikuni jets won't fix a defective carb and I'll still pay the postage to get the Mikuni paper weight. I can fix the fuel screw threads or use the rest of the parts to fix another skeleton that I laying around.

Engines are pretty simple - air in air out - right amount of fuel mixed with the air - compression - spark - spark at the right time and it will run. Performance? That has to do with valve lift - valve timing - valve overlap - spark advance.

So I suggest you pay attention to air getting in and out, the compression and valve lift. A clogged exhaust will let an engine idle, but not accelerate.
 
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