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Discussion Starter #1
Hey everyone,

It’s been about a year since I’ve last ridden my 07 YFZ450. It’s kept inside and has very low hours since I bought it new over a decade ago but have always kept up on maintenance regularly. Decided to pull it out the other day to flush all the fluids, throw in a new battery, etc and get it back up to spec for some riding this summer. When I turned the gas value to on, coolant started rushing out of the bottom from two different hoses at a very fast rate until I turned it back off. Does the same when on the reserve setting as well, but stops as soon as I put it back to the off setting. At first I thought it was probably the water pump seals as I saw many posts about it and planned on doing the full crankshaft removal and replacing all the seals. The more I thought about it though, the more I realized that none of those threads mentioned anything about the fuel value being on or off, and seemed to be more of a drip rather than a full flow like my issue is. I checked my oil and there is no milkiness or coolant in it. Looks very clean. I have attached photos as I don’t remember ever seeing the second hose there before, but didn’t see anywhere that it could have came disconnected from.

Any help is appreciated! Thanks

93560

93561
 

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I am convinced that this is fuel. Carbs with a stuck or leaking float needle are fairly common especially when the bike sits for a while. Also, old gas looks and smells nasty (sometimes greenish in color).

Your carb has five vent hoses so the fluid (fuel) is likely coming from those - especially the main float bowl overflow vent hose. Trace these hoses carefully and you should find your way back to the carb.

Sounds like a carb rebuild, or at a minimum a new float needle and/or seat (I wwould recommend changing both and thenseat cartridge o-ring too. If you rebuild the carb completely, do not neglect to clean and replace seals in the mid-body. So many carb bikes that are hard to start or that run rough at throttle positions other than WOT are due to gunked up mid-bodies.
 

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Discussion Starter #3
I am convinced that this is fuel. Carbs with a stuck or leaking float needle are fairly common especially when the bike sits for a while. Also, old gas looks and smells nasty (sometimes greenish in color).

Your carb has five vent hoses so the fluid (fuel) is likely coming from those - especially the main float bowl overflow vent hose. Trace these hoses carefully and you should find your way back to the carb.

Sounds like a carb rebuild, or at a minimum a new float needle and/or seat (I wwould recommend changing both and thenseat cartridge o-ring too. If you rebuild the carb completely, do not neglect to clean and replace seals in the mid-body. So many carb bikes that are hard to start or that run rough at throttle positions other than WOT are due to gunked up mid-bodies.
Thanks for the response! I will definitely check into this. Need to fully pull it out of the garage and take a look this weekend. What you described makes much more sense
 

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An antifreeze leak can be caused by many different things: A blown head gasket can allow your coolant and engine oil to mix. An antifreeze leak can occur through a hole in your radiator. Corrosion of your radiator tubes or damage because of stones or debris can create a leak.
 
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