I am no stranger to this forum, but I am new to the f1..
I purchased an '87 the other day so I could teach my wife how to ride and then later we could rebuild it together.. So I had it out in the driveway warming up and it fell over in its right side and died a few seconds later.. The bike will still start and idle but fuel now pours from the left side overflow tube between carb 1 and 2.

What causes this problem? Is it the floats, or something like that that gets stuck open? I am about to take the tank off and show her how to pull the carbs but I was hoping someone could shed a little bit of light on this..

 

Anybody?? I am really lost on what I should do now.

 

Wife and I took carbs apart this morning. They are fine, jets are clean and floats are all adjusted, cleaned float valves as well. Fired bike up and it still has gas coming out of the overflow tube. I let the bike run for a minute and sprayed some water on the headers, cylinder #3 isnt firing..

 

Ok so I figured out that if you turn the fuel pump off everything runs fantastic, but if you hook the pump back up it floods the carbs and leaks all over again.

Does anybody know if I can just leave the fuel pump off? I know that sounds like a stupid question but some fuel pumps on bikes just maintain pressure at higher speeds. Does this one still let fuel through?

My next question would be can I just bypass the pump all together and just gravity feed the carbs straight from the tank?

 

The higher pressure of having the pump on is most likely blowing past some o-rings. You probably need to replace the o-rings on the ends of those T-piece tubes, happened to me. Generic o-rings from a multi kit won't fit as these are a low profile, had to get them from the dealer, any that I tried were too "tall" to fit back into the carbs. You have to take the carbs off the retainer bar and separate them to pull the T-pieces. I'd just buy a rebuild kit if you are getting that far into them and change all the O-rings in all 4 carbs, then you will need to sync them.

Not running the pump will run the bike lean and will be a lower pressure (most likely low enough to not flow past a worn o-ring but still run the bike).

 

Very possible, I am going to take the carbs off and do a leak test in a few minutes.. Whatever si wrong with them happened because the bike tipped over.

 

the drop jolt could have shifted them some and rolled a stuck o-ring or cracked it if it was worn. With mine, when I took the T-pieces out the o-rings were flat even with the plastic, so they were just worn and not sealing.

They were working fine until I took the carbs off but not apart, put them back on and it was leaking, because I moved the T-piece around to get the fuel supply line off I broke whatever seal was there, so I'm thinking you dropping it moved the part some like I did and just pushed that o-ring from 99% to 100% needing replacement.

Make sense? let me know what you find.

 

Makes sense, but the leak is actually fuel coming directly out of the overflow tubes. So it leads me to believe that a float is sticking open and when I turn the pump off the fuel level no longer rises in the float bowls causing the leak to stop and the fuel to burn off, but when i hook the pump back up it fills the bowls and one or 2 of the float valves dont seal causing the carbs to flood and the fuel to run out of the overflow tubes.

I got the bike pulled back apart but figured I would mow the lawn while i still have daylight. I will crack open the carbs and let you know what i find as requested..

 

If you take the carbs apart, the part that the float attaches to that threads into the carb (10mm I think and it has the little screen filter in it if I remember correctly), there is a washer between each of those parts and the carb itself, those can screw things up too if they are squashed or missing if the carbs were rebuilt before and those weren't put back on, those would cause fuel to flow out the tubes too.

I know this only happened after it was tipped over, but something is definitely off here.

 

Just an update.. I have been out of town on a job for about 2 weeks but I came home yesterday and fiddled with the bike a bit. Turns out one of the floats was sticking open and causing the bowls to overflow from the t's.. Gave them one more really good cleaning and everything is groovy now!

I just hate leaving unanswered threads so I figured I would give you guys the update on what the solution to my carb problems was.. Hopefully it will help someone out in the future!