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I have a 1987 kawasaki ninja. I've had it for two years and it ran good until this year. When I started it this week, gas started to flow back into air filter box. Has anyone ever encountered this?

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If the float valve in one of the carburetors sticks it can force fuel up into the throttle body. Sometimes tapping on the side of the float bowl(s) will un-stick it. If the carbs have never been cleaned it may be worth doing this.

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Best to check the intake valve seals. If the shim is too large it won't allow the valve to seat properly, allowing pressure to be pushed back into the carb.

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Register your account. You'll be glad you stayed... :-) – DucatiKiller Apr 22 at 7:44

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