gas tank leaks and i cant figure it out!

[danmac86]

hello, this is my first post so i hope that you can help me...
i bought a '04 gs500f a couple of months ago, i really like this bike!  about a month ago though, gas started leaking out of the airbox drain hose.  i checked the float levels and they were fine, i checked the diaphrams and they looked ok, the vent hose to the bottom of the gas tank is open and clear, so i figured that the needles and seats in the float bowl must not be sealing so i took them apart and cleaned them.  after i put the needles back in it didnt leak gas... for about 2 days.  now it leaks hardcore from both carbureators, im kind of stumped!!  anything else that im not thinking of??   i was thinking about buying new needles and seats to put in it, but they are so expensive that i want to be sure that will fix it.   

also, im getting tired of wrestling this factory air box in and out everytime i work on it.... im thinking about putting some k&n filters on the carb. air horns, what size jet would i need to make it run right?? 

thanks for any help!   

[danmac86]

oh, i forgot to mention...  those 2 days it didnt leak gas and now that it leaks gas again, the bike acts flooded when you try to start it (have to hold the throttle wide open till it clears out and starts)

[wiltse]

take your tank off and examine the bottom of it for pin holes and also check all of your fuel lines and connections... if you find a hole in the tank you can use copper pipe and flux core solder to seal the hole,,, il explain more if you need me to

[danmac86]

ill check the tank tonight, but im having a hard time understanding why this would make the carbs leak??  there was a hose that was leaking when i first got the bike, but i quickly replaced that. 

[beRto]

If the airbox is getting flooded with gas, your carb float valves must be leaking. It seems like you have looked at the right things so far (float heights, float needles & seats). How did you check these? Here is an easy way to check float heights:
http://www.bbburma.net/FloatHeight.htm

Perhaps you can post a photo of the float needles?

Also, are you parking the bike in the PRI petcock setting? If the petcock is set to ON, the carbs shouldn't flood even if the floats are bad. If ON still leads to flooding, there may be something wrong with the petcock.

[danmac86]

i used the float checking trick this website shows to check the floats, and yes i leave the bike in the "on" position on the petcock...  i didnt think of that, would any gas in the lines still leak through the carbs?

[beRto]

i used the float checking trick this website shows to check the floats, and yes i leave the bike in the "on" position on the petcock...  i didnt think of that, would any gas in the lines still leak through the carbs?

If the petcock is working properly, it will not leak in the ON position because the fluid pressure from the gas tank will have been cut off. The fuel remaining in the lines will not really be able to run out because the lines are at a lower elevation than the carbs.

Remember that even if the petcock is bad, your symptoms still point to a problem with the float valve system.