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Hey guys new to the forum and new to kawasaki bikes in general but I recently picked up this 1999 kvf 300 that supposedly was having carb issues. I noticed when i first got the bike the crank case was filled with fuel/ oil. Ive replaced the carb but it is still filling the base with fuel. Just wondering if anyone else has had this issue? Im thinking it may be the petcock but i would like your imput. Thanks guys
 

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Welcome to the forum, Fuel tap could be suspect and it could be the carb float valve as well , it should seal to stop fuel flow ,but it might be overwhelmed by a bad Petcock, do you have a Workshop manual
 

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I agree with Ropp. This is a common problem on older vehicles. The root cause is a stuck float or bad float valve. Ordinarily if your KVF has a vacuum operated petcock, this should prevent the carb overflow but it sounds like you either don't have a vacuum operated petcock or you have one but it is malfunctioning. Both need to be fixed.

The odd thing is that your new carb did not fix anything. Was the carb used or new? If the tank has dirt in it, the dirt could have jammed the float valve.
 

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I agree with Ropp. This is a common problem on older vehicles. The root cause is a stuck float or bad float valve. Ordinarily if your KVF has a vacuum operated petcock, this should prevent the carb overflow but it sounds like you either don't have a vacuum operated petcock or you have one but it is malfunctioning. Both need to be fixed.

The odd thing is that your new carb did not fix anything. Was the carb used or new? If the tank has dirt in it, the dirt could have jammed the float valve.
I put fresh fuel in it, brand new carb i forgot to mention the bike is running flawlessly but still filling the base. I don’t believe it has a vacuum operated petcock though it may. (Has two lines coming from fuel tank into petcock and one line from petcock to carb) not sure if one of those lines from the tank is a vacuum
 

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Fresh fuel is good but will do nothing to remove the rust or dirt that may be the source of your troubles. A vehicle with a stuck float or float valve can operate normally because the engine's demand for fuel exceeds the amount that would otherwise leak. However when the engine is turned off the flow of fuel continues and this will end up in the base of the engine with very harmful effects.
 

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Thanks for your advice, i believe im going to take apart the petcock and clean it and clean the new carb, hopefully it helps
 

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Understood. The leakage might be only a few drops of gasoline per minute. Make sure the float can move freely and check the float level also.
 

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float valve is not sealing

on 300's, kawasaki used those STUPID Keihin carbs that didn't have replaceable float valve seats, so when the seat wears all you can do is replace the carburetor with a new one and they ain't cheap

once in a blue moon you can buff the seat with a q-tip and some toothpaste then clean it out perfectly before putting the carb back together. U can't leave ANY of the toofpaste in there or it will stick open and flood the engine quickly

there are some chincanese copies out there for like $80 or so, but they are hit and miss in my experience you might get one that works perfect and the next one (exactly the same) is nowhere near close. Throw it away and buy another until you find one that is close enough to suit your needs

replace the fuel valve on the fuel tank the older stuff isn't compatible with newer oxygenated fuel. Replace the fuel lines too, both of them. There are three on the prairies and they are oddball pre-molded, with one end much larger than the other. I never found anything that "would work" other than the $50 worth of 3 fuel lines from Kawasuki.

lastly if the engine is running rich, that too will build crankcase vapors in the crankcase. So will frequent short trips. Mules have this problem every year from about November through April, I've had discussions (arguements) with customers who said that their 610 had a "blowed head gasket" cause the engine oil was rising and sometimes milky; he'd change it 2 or 3 times in the winters and come June? Problem disappeared....with frequent short trips, normal blow-by gases build up in the crankcase and the oil never gets hot enough to evaporate those vapors out. The cure? On Mules, their governed. Toss it into low gear, floor it and leave it on the floor for about 5 minutes minimum. Does not apply to Pro FXT's, FXR's, any of the Mules with the 3 cylinder Chery engine. Only the Mule 4010 and smaller they are all mechanically governed lawn mower engines that are designed to run 3500 RPM at full load all day long and in a Mule, they just sit and idle most of the time.
 

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I have heard of carbs with non-replaceable float valve seats and have to wonder what on earth was the designer thinking?

Yes it might reduce the manufacturing cost of the carb by a couple of dollars, but come on, we all know that this is a wearable item and needs replacement from time to time. To have to buy a new OEM carb for hundreds of dollars just because the valve seat is worn is beyond ridiculous if you ask me. :mad:
 

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you can call keihin and thank them.

keihin builds a lot of non replaceable seat carbs for OEM's

Honda is one kawasaki is one and I've seen them on polaris and zuki too.

sometimes you can buff them as mentioned above. Really worn ones I have had "some" "luck" by the following. Take your old float valve, put a tiny bit of fine valve grinding compound on the tip, then put the coated valve into the seat, and turn it back and forth a few times. This "buffs" the seat. So long as the seat is not severely damaged it usually works but not always. Then once you're done there you can use some toothpaste on a short Q-tip to lightly buff it out so that the valve will lift/lower smoothly without binding. Afterwards it needs to be 100% clean, and that doesn't mean hit it with the carb cleaner and call it good. I generally soak them for a while in the heated ultrasonic, use a clean dry Q tip to wipe it all out, blow through it, inspect via nice bright flashlight, etc. If you leave ANY compound or toothpaste in the seat, it will cause the float valve assembly to leak again.
 

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It would be nice if someone designed and sold a valve seat re-cutter just like we have for our engine intake and exhaust valves.
 
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