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petrol is leaking into one of the cylinders on my vfr 400 nc30?

My vfr 400 nc30 leaks petrol into one of the cylinders.... ive removed the carbs, checked everything, the float heights, the float pin and seat, and they are all in good condition. what could be the problem? i remove my carbs and every time there is petrol all the way up to the top of one of the cylinders.... please help i dont know why it is doing this. ive even tested my carbs while its on a table.. i put fuel in via the fuel line.. and the carb isnt leaking any petrol!

ive also asked and im waiting for a reply, so while i wait, i want to ask here too.



Mark there is a fuel filter, i think im going to swap one of the pin and seat from the other bowls, then i will know for sure if its the float seat ad pin, because only one of the carbs are leaking not the others.

2 Answers

  • Mark
    Lv 7
    8 years ago
    Favorite Answer

    Its either the float heights, the float pin or seat or you have crap in your fuel ( I know you checked them). I would replace the pin and seat and put in a fuel filter.

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  • 8 years ago

    Agreed. It's the float needle allowing fuel to pass. Either float height, or debris holding it open. The only way for fuel to get into the cylinder is through the carburetor so that's where your problem lies. BTW, there should be an overflow tube that allows that gas to pour out on the ground rather than into the cylinder. Check if it's clogged. I once bought a bike where the idiot had tied the end of the hose off to stop it from leaking. The gas had nowhere to go but into the cylinder and filled that and part of the air box. Stupid people shouldn't be allowed to own motorcycles.

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