TOPIC:

I have an ongoing problem with carbs flooding and I am looking for some opinions. My carbs were flooding and I changed my fuel tap for a spare GT750 one that I had, that seemed to cure the problem until yesterday. I had done a couple of hundred miles since I changed the tap and the bike was running lovely, but yesterday about 10 miles after filling up I got stuck in some traffic and the bike started missfiring. When I got home some fuel flooded out the bottom of the airbox, but stopped as I now have a vacuum tap, when I put it to prime it started flooding again. I removed the top of the airbox and saw that the fuel was coming out the middle carb, so I took them of and checked the float valves which were clean. I Put the bike back together and it seems to be running OK again. I suspect that the problem I have is my fuel cap, it has been replaced with a pattern one which doesn't utilize the vent system but apears just to vent through the key slot, when I fill the bike up I am getting fuel coming out of the cap, I think my problem is that the cap is not venting properly and when I get in slow traffic the heat from the engine is expanding the fuel and vapor in the tank which in turn is causing a positive pressure which is enough to overcome the float valves and flood the carbs., I have the original cap but the chrome is bad, another thought I had was to drill a small hole in the cap an fit a nozzle and a small hose like what the old trail bikes had, I would be grateful for any suggestions.

I do not think its your fuel cap
I thing the float valve getting stuck or the diaphragm get stuck up and keep the needle up

Eran

Put the original gas cap on the shelf until you can have it rechromed.  Don't be drilling any holes in it !

"I thing the float valve getting stuck or the diaphragm get stuck up and keep the needle up"

The position of the diaphragm/high-speed needle has no relevance.

I do agree however that there's a good chance your float-needle is getting hung up by the retaining spring if they are aftermarket parts.  


 

found it its definitely the cap is restricted,it started doing it today and I loosened the cap and it stopped right away and was fine for the rest of the day.

This whole gas tank venting came up 4 years ago and rather than rewriting it again, please see/review this link.

Gas tank venting system Topic
 

For the sake of completeness, I'll share that I heard that a guitar string (one of the larger, wound ones) chucked up in a drill makes a great "Roto-Rooter" to clear the hard line part of the vent.

Just take it very slow in the beginning, because the guitar string will twist itself up in knots if you try to rush it. This trick allowed me to clear a blockage that nothing else would shift.

This chewed up the rubber seal under the fuel cap, but I know somebody out there sells them. Can't remember who.

Richard