2001 GS 500, stock except for rejet, 15,000 miles
I rebuilt the carbs (new needle valves and needle valve seats) earlier this year after I picked up this project bike. I thought I had worked out all the kinks, but now I have this one. On several occasions, after a ride of 15-25 miles, I notice fuel dripping from the airbox overflow after I shut the machine off (it will drip a small stream, then nothing for about 5 seconds, then another small stream, etc.....). This happened really bad one time while I was out and about and had to trailer the bike home because of excessive fuel dumping out of the overflow. I figured the float hung up. I took it apart (being careful to keep the carbs right side up to see the condition that they were in at time of failure), but found everything in working order. 99% of the time that I have this issue is the 1st time I shut it off after turning the petcock to reserve while riding it. I have taken off the fuel lines and tested the petcock in all the positions and it works fine. I took the fuel cap assembly off yesterday and cleaned the vent out real good with carb cleaner to rule out the "burp" effect". I had a full tank of gas when I took off for work yesterday, got to work and popped the gas cap off and heard no rush of air.......rode home last night and pulled in the garage and popped the gas cap and again, no rush of air. I put the old cookie pan underneath it as always just in case of any leaks and went to bed thinking all was good,,,,,,,,,,,,,,,,,,Checked this morning and saw a little bit of fuel in the corner of the cookie pan...not alot, but a measureable amount.........
-Is this normal?
Not normal. What is the fuel level using the u-tube method?
Quote from: Paulcet on March 08, 2012, 06:25:17 AM
Not normal. What is the fuel level using the u-tube method?
Haven't tried the clear tube method yet, but I set both floats at 13mm +/- 1mm per the manual when I rebuilt them.
I did the clear tube method before I came to work. The left side setteled in the tube right at the bowl/carb body line....the right carb leveled at least an inch above the bottom of the carb body......Dammit...WTF is wrong with the float in the right carb? I have checked and re-checked it several times and put new needle valves and seats in it......
Quote from: craigs449 on March 08, 2012, 02:43:21 PM
I did the clear tube method before I came to work. The left side setteled in the tube right at the bowl/carb body line....the right carb leveled at least an inch above the bottom of the carb body......Dammit...WTF is wrong with the float in the right carb? I have checked and re-checked it several times and put new needle valves and seats in it......
Rap on the RS carb body with a screwdriver, see if the level changes (shake the bike) after bumping the starter.
I'm betting the float needle BORE is worn, and making the float needle stick open. The tiny amount of fuel after the petcock makes its way in.... then to your floor.
Pm me if I'm right.
Quote from: ohgood on March 08, 2012, 04:23:10 PM
Quote from: craigs449 on March 08, 2012, 02:43:21 PM
I did the clear tube method before I came to work. The left side setteled in the tube right at the bowl/carb body line....the right carb leveled at least an inch above the bottom of the carb body......Dammit...WTF is wrong with the float in the right carb? I have checked and re-checked it several times and put new needle valves and seats in it......
Rap on the RS carb body with a screwdriver, see if the level changes (shake the bike) after bumping the starter.
I'm betting the float needle BORE is worn, and making the float needle stick open. The tiny amount of fuel after the petcock makes its way in.... then to your floor.
Pm me if I'm right.
I replaced the needle valves, valve seats, and valve seat o-ring when I rebuilt them. Is this something different than what you are referring to?
I had a problem similar, clean and clean the carbs replace the float needles, set the floats and still leaked gas out the overflow. It came down to I was getting small pieces of trash under the float needles causing them to stick. Just a thought, it drove me crazy finding what was going wrong after taking the carbs apart a thousand times.
04 500f
Timing mod
Pilot 20
Mid 60
Main 132.5
Yoshimura rs3
K&n drop in
Quote from: wolfs02shadow on March 08, 2012, 06:57:45 PM
I had a problem similar, clean and clean the carbs replace the float needles, set the floats and still leaked gas out the overflow. It came down to I was getting small pieces of trash under the float needles causing them to stick. Just a thought, it drove me crazy finding what was going wrong after taking the carbs apart a thousand times.
04 500f
Timing mod
Pilot 20
Mid 60
Main 132.5
Yoshimura rs3
K&n drop in
Good advice, but I added inline fuel filters on the fuel supply lines from the tank when I replaced all the lines and rebuilt the carbs. I am pretty sure they would catch any little bits of garbage in the fuel before making it to the carbs.
Well, looks like I am gonna take these suckers off again and see what the issue is now. I am gonna triple check the float heights and see if I can test them this time before putting it all back together.
Quote from: wolfs02shadow on March 08, 2012, 06:57:45 PM
I had a problem similar, clean and clean the carbs replace the float needles, set the floats and still leaked gas out the overflow. It came down to I was getting small pieces of trash under the float needles causing them to stick. Just a thought, it drove me crazy finding what was going wrong after taking the carbs apart a thousand times.
04 500f
Timing mod
Pilot 20
Mid 60
Main 132.5
Yoshimura rs3
K&n drop in
This would explain things though.......when I have had this issue and taken the carbs off, I only checked to be sure that the floats were not hanging up on anything and were in proper working order. Since I replaced the needle valves and seats, I haven't checked inside there or cleaned the seats because I assumed they were good to go as long as they worked properly. I am hoping to get it apart (again) today and see what's going on.
Thanks for the advice. :thumb:
Check your filter to see if it's catching any trash and when your fuel line is off pour a little out into a container and check it.
04 500f
Timing mod
Pilot 20
Mid 60
Main 132.5
Yoshimura rs3
K&n drop in
Quote from: craigs449 on March 08, 2012, 06:09:52 PM
Quote from: ohgood on March 08, 2012, 04:23:10 PM
Quote from: craigs449 on March 08, 2012, 02:43:21 PM
I did the clear tube method before I came to work. The left side setteled in the tube right at the bowl/carb body line....the right carb leveled at least an inch above the bottom of the carb body......Dammit...WTF is wrong with the float in the right carb? I have checked and re-checked it several times and put new needle valves and seats in it......
Rap on the RS carb body with a screwdriver, see if the level changes (shake the bike) after bumping the starter.
I'm betting the float needle BORE is worn, and making the float needle stick open. The tiny amount of fuel after the petcock makes its way in.... then to your floor.
Pm me if I'm right.
I replaced the needle valves, valve seats, and valve seat o-ring when I rebuilt them. Is this something different than what you are referring to?
no, you did the right stuff. just look at the bores that the needle floats ride in. if there is varnish / trash in there it will keep them from moving freely = leak
any amount of trash under the seat of the needle float will cause a drip or stream. :)
Pulled the carbs off today and found both floats and needle valves in working order. I pulled the float and needle valve off the right carb to have a good look inside the seat and noticed an imperfection in the brass near the small end of the seat. I pulled it off and hosed it down with carb cleaner and it looks like that might have been my issue. almost like somebody barley touched it with a Dremel tool and caused a divot. I am assuming that the needle most of the time was able to seal it up with the rubber, but sometimes it could'nt seal it and I had leaky gas. I pulled the o-ring off the new seat and fitted it to one of the old ones I kept from the rebuild and buttoned everything back up. Started it and all seems well for now..........I will check it again when I ride her into work tomorrow.
Thanks for all the advice/replies :thumb:
-Craig