Carb Rebuild Gas pouring out

[Spootinay]

damn I forgot to mention that picture of the float is just an example of the types of floats i have.

all four of my floats are sealed (boiling water test) and intact (no dents)

what is the spec for those types of floats on those carbs?

[mack]

float height

25.7mm to start. Roll your carbs over so they're sitting on the tops flat and level. Hook up your gas lines to the T's closest to the bowls and check to see if the float valves leak first. Leave the bowls off for this one. Remember to lift the floats until a bit of gas comes out as you have to remove the trapped air first. Dry everything with Q tips then sit and watch for 10 minutes to see if the leak is at the float valve and needles first. If they don't leak there then we'll progress to the next step. What type of float valve needles are you using?IE do they have the black rubber tips or are they bare metal? Also look at the needle seats and ensure they are polished smooth and shinny so the needles seat properly if they do leak at this step. For thoughs carbs the float valves are threated. Whatch around the shoulders to see if the leak isn't in the thread as well. Get back to us and well walk you through the next step. P.S Don't burn the bikes. This is frustrating , but an easy repair.

[James England]

I'm beginning to wonder of the butterfly seal thing is a bit of an urban myth or rather overrated? I mean, every time someone mentions carb problems, somebody comes back with the butterfly observation, like it's some sort of chant and response...... Those seals were use in loads of carbs throughout the 70's and 80's and I've spoken with carb rebuild people who flatly deny that they are as fragile or temperamental as people seem to think. On some carbs, these seals actually have a hole in them by design. I've heard of people ultrasound cleaning them with no ill-effects and I've sprayed them with carb cleaner and dunked them in all sorts of things without any problems,

Having said that, I'd be interested to hear from people with actual experience of mishaps with the seals due to soaking or whatever. As you know, I'm a contributing member of the forum and value it immensely, so I'm not being disparaging.... it's just sometimes I get the impression that little nuggets of what might be disinformation circulate, get re-used, requoted and then become the gospel truth. See what I mean?

[DAVINCI]

+1 on that, James. I feel the same way on the floats-crushed-by-compressed-air theory. My opinion, for whatever it's worth, is that the crushed float is caused by too many winters outdoors. Water buildup in the bowls freezes and crushes the float. Of course, I'm talking about a bike that's been pretty much abandoned outdoors for a few seasons.

[jetmechmarty]

James,

I soaked my XS650 carburetors in carburetor cleaner many years ago. I still don't have evidence of them leaking. Some of the butterfly seals on my XS1100 were passing some air, so I replaced all of them. As far as the 11, I don't know what caused them to fail. I suspect it was just age.

[jetmechmarty]

FWIW, I just found the butterfly seals at $2.43. I think that's each.

http://www.yamahasportscenter.com/fiche_select.asp?mfg=Yamaha&partnumber=256-14997-00-00

[BA80]

I'm beginning to wonder of the butterfly seal thing is a bit of an urban myth or rather overrated? I mean, every time someone mentions carb problems, somebody comes back with the butterfly observation, like it's some sort of chant and response...... Those seals were use in loads of carbs throughout the 70's and 80's and I've spoken with carb rebuild people who flatly deny that they are as fragile or temperamental as people seem to think. On some carbs, these seals actually have a hole in them by design. I've heard of people ultrasound cleaning them with no ill-effects and I've sprayed them with carb cleaner and dunked them in all sorts of things without any problems,

Having said that, I'd be interested to hear from people with actual experience of mishaps with the seals due to soaking or whatever. As you know, I'm a contributing member of the forum and value it immensely, so I'm not being disparaging.... it's just sometimes I get the impression that little nuggets of what might be disinformation circulate, get re-used, requoted and then become the gospel truth. See what I mean?

I tend to agree James. I've soaked a lot of carbs in GUNK carb cleaner an I don't recall having ruined any shaft seals. It's possible that they could be damaged if the shafts have been removed but if your going to remove the shafts you might as well do those seals anyway. IMHO

[DGXSER]

Alot of misdirected info here it seems, first because the butterfly seals will never be a cause of flooding carbs which is what the thread was dealing with. Now that being said, I am sure it is like anything else, it is only a danger if done XSively. I can drink a beer and still ride or drive without issue, but after a case or two, well, probably should not. So spraying them with carb cleaner, dunking them in carb cleaner and scrubbing most likely will not harm them, even soaking them for a period of time may not ruin them.

But how long is to long and how much is to much, all depends on alot of things. So on the side of safety, us shadetree types that work on stuff for a break form normal every day hussle and bussle of life and do not know those answers get suggestions of not doing it all all as it can be avoided and still get the carbs clean. As much of a complete PITA as it is to change them, since most of us do not even break the carbs apart to clean them, let alone peen out those tiny little screws and all that stuff, I would definitely not go to the trouble of changing them out till they show definite signs of leaking.

[jetmechmarty]

Alot of misdirected info here it seems, first because the butterfly seals will never be a cause of flooding carbs which is what the thread was dealing with.

Yep. When they leak, they allow air to pass. Don't most threads go off on a tangent?

[BA80]

Yep. When they leak, they allow air to pass. Don't most threads go off on a tangent?

Don't they though. However, so do good conversations.

[Spootinay]

25.7mm to start. Roll your carbs over so they're sitting on the tops flat and level. Hook up your gas lines to the T's closest to the bowls and check to see if the float valves leak first. Leave the bowls off for this one. Remember to lift the floats until a bit of gas comes out as you have to remove the trapped air first. Dry everything with Q tips then sit and watch for 10 minutes to see if the leak is at the float valve and needles first. If they don't leak there then we'll progress to the next step. What type of float valve needles are you using?IE do they have the black rubber tips or are they bare metal? Also look at the needle seats and ensure they are polished smooth and shinny so the needles seat properly if they do leak at this step. For thoughs carbs the float valves are threated. Whatch around the shoulders to see if the leak isn't in the thread as well. Get back to us and well walk you through the next step. P.S Don't burn the bikes. This is frustrating , but an easy repair.

i have the bare metal float valve needles. Ill do as suggested and get back asap

[crazy steve]

If you replaced the float bowl gaskets, you might want to trim the excess gasket inside at the sides of the gasket surface; some aftermarket gaskets are wider than they need to be there and the floats can hang up on them. A nice sharp razor blade will work....

[DGXSER]

Yep. When they leak, they allow air to pass. Don't most threads go off on a tangent?

Yes they do, and I am sure I take some that way, so not intended to malign the thread direction, just to make sure no one reading it would think the two issues were linked. I know in my early days of mechanics and such I could easily have been lead to believe they could.

[jetmechmarty]

Don't they though. However, so do good conversations.

What, pass air, or go on a tangent?

[BA80]

I guess that would depend on the person posting and what they have to say marty.