Recently I noticed these two hoses sticking out right besides the gear shifter on my 2008 Honda Hornet CB600F. I have never noticed them before, and I don't think they were sticking out like this when I bought the bike.

What are these hoses? And should they be connected to anything?

I couln't find anything that looks like these hoses should be connected to. The other end, of the thicker hose is connected to the coolant resevoir under the seat, the other hose, I was unable to trace.

On the internet I found that one hose is a "coolant overflow hose" which seems strange to me, because when would coolant ever overflow except when filling it up?

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2 Answers 2


Those are the fuel tank overflow and coolant overflow hoses. A very full fuel tank can sometimes overflow a bit because of heat and sloshing around, overheating coolant causes pressure which needs to be released, the overflow hoses are there to channel gasoline and hot coolant away from the rider and onto the ground so you don't start on fire or get severe burns. They are a good thing™.

Sometimes those hoses can get positioned wrong, just make sure they are pointing straight down.


One is fuel tank breather (used to let air into the fuel tank) also overfill hose when you fill your tank let it in sun gasoline might expand and overfill. other one is coolant overflow ( when you fill too much coolant and when coolant get hot it expands and might overflow ) nothing to worry about those exist on every bike.

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