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Hey all! I’m new here and have some questions in regards to my 99’ Yamaha YZ400F.


Got the bike for a deal. $1000 bucks. Has the Keihin FCR carburetor on er’. Guy I got it from said that about 40hrs ago it had top end rebuilt. I believe him because it has excellent compression and will break your ankle if you don’t time the kick the way you should. Only issue It had was it wouldn't stay running unless choke was pulled. No big deal. Got a carb rebuild kit, cleaned jets and holes, put her back together and It started up after 3 kicks and ran as it should. Rode it around for maybe 5 minutes, everything seemed great! 30 minutes go by after getting ready to go ride, I decide to fire it up again to make sure it works still. This time when it started up she was smoking blue smoke like a diesel in -30° weather. Smelled heavily like burnt oil and had a very blue color to it. Stumped, I figured maybe float needle was stuck open and fuel filled into crankcase and overfilled it (dipstick was reading super high). Checked needle and seat height, drained and changedoil/filter. Put in the 1.2-1.3 quarts, kick started it and it fired up: no smoke! Until 10 seconds go by and it’s smoking like a chimney again. Shut it off and checked dipstick and no oil registering. Fired it up again with blue smoke and all to let it run a little. Shut it off…. Dry dipstick…. If I let it sit for maybe 10 minutes and fire it up, it won’t smoke initially and then turns into a chimney after around 10 seconds.  I’m stumped. Any wisdom on what’s going on?


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