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YZ400F Gas dripping out of exhaust upon starting

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Hi guys, I just bought a 1998 YZ400F and I got it home and when I go to start it a couple kicks in, it starting dripping and pouring gasoline out of the muffler and will not start. I am not really familiar with dirt bikes, does anyone know what can be causing this? I also pulled the spark plug and it was dripping with gas. Any help at all is appreciated.

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DO NOT RUN THIS MOTOR until you fix the problem

It can catch fire or explode the exhaust pipe!

 

1. Buy a service manual

2. pull the float bowl and replace the float needle, and inspect the seat for pitting

3. set your float height to factory specs

4. that is a very old motor, and you probably should service the whole carb due to wear, corrosion and possible neglect

 

http://www.dirtrider.com/features/protips/141_0707_keihin_fcr_carb_rebuild/

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Well I figured out why the gas was coming out the exhaust, the float in the bottom of the carb was stuck down, and letting max fuel in all the time. I took the carb apart and cleaned it all up, and it seems to be working good now. No excess fuel coming out. Now the only problem is that it won't fire by kickstarting, it will start if I have someone pushstart me though. When I got it running, it was smoking pretty good, like a whitish, with a slight blue tinge. It seemed to get better after a few minutes to where it wasnt smoking at idle, but if you revved it up it would smoke. It had been sitting for about 6 months over the winter without being started said the guy I  bought it from. I ran out of time to keep running it last night. Does anyone have any ideas why it's smoking? It seemed to have really good power still, really responsive, maybe the mixture isnt set right?

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White/blue smoke is oil, and lots of it, to make it really visible.

 

You probably need to rebuild the head on a motor that old

 

Oil would come from leaking stem seals and/or worn out/stuck rings

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White/blue smoke is oil, and lots of it, to make it really visible.

You probably need to rebuild the head on a motor that old

Oil would come from leaking stem seals and/or worn out/stuck rings

If he had that much gas in it, wouldn't it mix with the oil and thin it out making it slip past seals and such and smoke? I think he needs to flush his out out first thing,.

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If he had that much gas in it, wouldn't it mix with the oil and thin it out making it slip past seals and such and smoke? I think he needs to flush his out out first thing,.

 

That's a really good point.

I'm so glad i thought of it.  :rolleyes:

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