Fuel Leak

[brianinpa]

So as I mentioned in another thread, I have a fuel leak from the crab, well it is actually just the right side of the carbs. What I found is that fuel is leaking out the the Joint Set, Air Vent. That is item # 10 in the picture below.

Air Vent

• brianinpa
• Dec 6, 2013

I am thinking a stuck float but not really sure. Any help or ideas?

 

[Ansimp]

Definitely sounds like a sticky float or poor needle and seat sealing for the float valve.

 

[slabghost]

It was running good otherwise right? I'd leave it and run ATF in the fuel. Maybe keep a screwdriver handy to tap that car until it cleans up.

 

[joedrum]

1200 floats work rather well compared to others brian ....hmmmmm.....1200 carbs have to be the easiest to work on in the bowl area ....leave the rubber slides and caps alone till you exhaust all other possible stuff no sense in taking this apart till last resort ....clean it up inside bowls and give the flow and flow stop test ...see if it passes

 

[brianinpa]

slabghost » Sat Dec 07, 2013 7:16 am[/url]":3vziw8er]
It was running good otherwise right? I'd leave it and run ATF in the fuel. Maybe keep a screwdriver handy to tap that car until it cleans up.

It was a bit rough until warm so I was thinking it needed to be synched, but yeah, seemed to run fine when warmed up.

1200 floats work rather well compared to others brian ....hmmmmm.....1200 carbs have to be the easiest to work on in the bowl area ....leave the rubber slides and caps alone till you exhaust all other possible stuff no sense in taking this apart till last resort ....clean it up inside bowls and give the flow and flow stop test ...see if it passes

Just wondering Joe, what or where is this test?

 

[slabghost]

Flow test he talks of is feed fuel on the bench to see if the float valve stops the flow.

 

[Joep]

Could be a twisted or cracked rubber seal that goes on the end of that crossover shown on both 10 and 11 and also on 8...... think ~O~ head one that went bad....right Randy? His may have been on an 1100 ...

 

[brianinpa]

I was thinking I wasn't going wait to look at these until I get it all back together again and do a tap dance with a screwdriver, but I guess I really need to open it up and take a look.

 

[brianinpa]

Well I got about 15 minutes of idling and about 5 miles of riding in before I started smelling fuel again and the fuel continues to leak from the Joint Set, Air Vent. Carbs are back off and the floats on the right side are opened up so I can see what is happening and nothing obvious. Nothing is stuck, bent, or out of place. The floats appear to be adjusted correctly too. I don't really want to dive into the carbs further than I have to, so any ideas?

 

[mcgovern61]

brianinpa » Fri Dec 20, 2013 12:53 pm[/url]":44i38hij]
so any ideas?

Yep!

My carb issues were two fold. When all floats were adjusted correctly, one still leaked!! Had to set it for 17mm to stop leaking.

Second thing is, the needle tips and seats looked and felt clean, but they were not sealing. I had to take them out three times and finally ran the needle tips over emory cloth and spun some in the seats. That finally did it.

I did all testing off the bike. My tank was full so reconnecting to the fuel line while on the ground gave enough head pressure to show leaks. One of the tests I did that proved most useful for finding the leaking carb was to let them sit on the floor for an hour with the petcock open and keep looking into the intake. Then I picked them up on a 45 degree angle left then right (simulating leaning into hard turns) and sure enough, old leaky showed up. That was the one that needed to be adjusted to 17mm.

 

[brianinpa]

Not to make myself look stupid, but it won't be the first time... :smilie_happy:

How.can you find a leaking seat if the carb is all closed up? Maybe I am missing something in the translation.

 

[mcgovern61]

brianinpa » Fri Dec 20, 2013 8:18 pm[/url]":10hhpns9]
Not to make myself look stupid, but it won't be the first time... :smilie_happy:

How.can you find a leaking seat if the carb is all closed up? Maybe I am missing something in the translation.

That dribble of gas that seeps out is coming from somewhere! :hihihi:

Once I determined the needles and seats were not sealing, I pulled the units apart to get to the seats for cleaning. If I remember correctly (and don't quote me on my memory) after cleaning I just put a needle in and would drop some gas in to see if it would seal with gravity alone. (It was a long time ago.)