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no start after top end rebuild

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I finally got my 04 rm 125 together after a new wiseco piston and replated cylinder. At first the bike started fine and ran fine for a bit then died out. Now it runs for about 10-15 seconds and just bogs out and does it everytime i try to start it but it will fire right up after it dies. it will also just die right out when i put the choke on. I checked the carb , jets, and needle and seat and everything looks fine. ive also adjusted the airscrew to leaner and richer and no difference. The petcock is also working fine also. any ideas? i did not touch the carb during the rebuild, and it ran fine before. I cant figure it out

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It sounds like it's getting too much gas. Is plug wet or dry? Did you check the float height? Check shut off valve on float to see if it stops fuel from entering carb when float is up? Air filter clean? I would take carb apart and clean good if you didn't do that. The bike sat while you rebuilt and may need a cleaning. And be sure to check the shut off valve to be sure it's stopping the flow of fuel. When the bike is running, it may vibrate enough to keep the valve loose and let fuel in.

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The plug is wet so you are right, it is getting too much gas. And i have checked the float height a few months ago and it was right on but i will check again tomorrow when i have the carb apart. And the airfilter is fresh. How can i check to see if the shut off valve is stopping the flow of gas? im thinking this is my problem

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this thing is kicking my ass. I checked the seat and it is seating correctly. I checked the float level and its at 12mm and the float "floats". I also cleaned the carb. now it will only run for a second and then die out and there is no gas running out the overflow. I adjusted the throttle cable while i was rebuilding... it would click at about half throttle and i was trying to stop that, but i have adjusted and adjusted and no difference.I cant think of what else it would be? any help at all would be appreciated...

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Try setting the float at 14 or 15 mm and see if that makes a difference. Are you measuring it from the metal surface of the carb where the gasket sits? While you have the carb out, remove the bowl and keep the fuel line hooked up. Put a container to catch the gas under the carb, turn on the gas, and lift the float up to make sure it stops the fuel from flowing. I would also change the throttle cable. You don't want that getting stuck once it's running and you're riding it.

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haha i knew it was something dumb.The tip of the spark plug was bent to the electrode and there was no gap at all. Put a new plug in and putting it threw heat cycles now. The only thing that bothers me now is how that plug got bent... i checked the top of the piston and saw no damage... and after 5 minutes of running with the new plug i checked the gap and it had stayed the same. But thanks for the help guys

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