Yamaha FZ-09 Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hi everyone,

i just bought my very first bike, 2015 fz09 with 1200 kms on it (newbie here lols) i noticed that there’s a small oil drip. Do i have to be concerned about it? Picture attached.

thanks in advance!! Ride safe everyone!!
165270
 

·
Registered
2016 xsr 900
Joined
·
962 Posts
Those are the fuel system vent hoses, if they are dripping it should be fuel, and indicates that you likely overfilled the tank, or maybe got a splash of fuel up around the fill hole
 

·
Registered
Joined
·
442 Posts

·
Registered
Joined
·
2,909 Posts
Those are the fuel system vent hoses, if they are dripping it should be fuel, and indicates that you likely overfilled the tank, or maybe got a splash of fuel up around the fill hole
And or you filled the tank and then parked it out in the sun the fuel expanded and dripped some out ..normal !
 

·
Registered
Joined
·
636 Posts
Five, possibly six years old and only 1200 km on it? Why is it so?
Interesting case. Very strange to have this most awesome bike just sit... Judging by the picture, the the stand looks mighty clean. ( seems legit ). LOL.
 

·
Registered
Joined
·
636 Posts
Those are the fuel system vent hoses, if they are dripping it should be fuel, and indicates that you likely overfilled the tank, or maybe got a splash of fuel up around the fill hole
And or you filled the tank and then parked it out in the sun the fuel expanded and dripped some out ..normal !
This right here is the culprit. psyco and abe57 hit it on the money. I overfilled my tank once, when I parked it at home in the hot sun, gas expanded and it dripped from those vent hoses.
 

·
Registered
Joined
·
125 Posts
This right here is the culprit. psyco and abe57 hit it on the money. I overfilled my tank once, when I parked it at home in the hot sun, gas expanded and it dripped from those vent hoses.
The heat from the sun could also be causing the gas to evaporate, creating a humid environment and causing condensate up in the gas cap area that gets caught by the overflow holes. So theoretically you could be getting drips in hot weather and direct sun even if the tank isn't full. This part is pure conjecture on my part, though

The thermal expansion coefficient of gasoline is approximately 950x10^-6 per Kelvin. If you pump 3.7 gallons of 70 degree F gasoline into the tank and it heats up to 120 degrees F it's volume will increase to 3.8 gallons, an increase 0.1 gallons or ~3%. So theoretically you should only lose a tenth of a gallon from thermal expansion with a change in temperature of 50 degrees. This is assuming the 3.7 gallon tank on my 09 actually only holds 3.7 gallons. Not sure how leaning the bike on its stand would affect the amount that would spill out.

Sources:
Thermal expansion of gasolines from 0 degrees to 30 degrees C (nist.gov) - OK, this data is from 1916. Finding a more recent source for the expansion coefficient.
1.4: Thermal Expansion - Physics LibreTexts - new source, looks like the coefficient hasn't changed
Thermal Expansion Calculator (omnicalculator.com)
 

·
Registered
Joined
·
442 Posts
No disrespect to the lucky (?) buyer of this 1200km/ 5 or 6 year-old bike - but if it were mine I'd be engaged with other age-related things before worrying about a minor oil/ fuel drip. Like - replacing the tyres, even the tires, which are probably nearing their use-by date at that age, especially if standing unused for so long. And replacing all fluids before riding - brake fluid, coolant, engine oil (and fitting a fresh filter). Having done all that, enjoy the bargain! ;)
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #13 ·
I live
i live in the Territories. We only have a good at least 2 months of warm weather. Lols
 
1 - 15 of 15 Posts
Top