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Float height from.....where?

Discussion in 'The Garage' started by davem222, Jul 8, 2012.

  1. davem222

    davem222 davem222

    Hey guys,
    Thought I had made a mistake, I had set my 79 bs38s with a float height from the lip of the carb body that overlaps onto the float bowl. I soon realized that the carb manual on here says it should be 24mm +/- 1mm from the surface that the gasket sits on. Sweet, so since that surface is 3mm below the top of the lip (from where I was setting it) I actually had it set to 27mm. I had some trouble getting my calipers down to the gasket surface, so I simply did it from the lip but only 21mm. Simple math, 21mm from floats to lip + 3mm to gasket surface = 24mm. Hooray! Checked both sides of each, bolted it on, turned on the petcocks: WOOSH, gas everywhere, coming out of the air filters, etc. Anyone have any clue what I'm doing wrong here? Could my floats be deformed? Do I not set it from the gasket surface?

  2. 5twins

    5twins XS650 Guru Top Contributor

    I think something's wrong with your float needles and their seats. Before when you had the floats set @ 27mm, which is 3mm too low fuel level wise, you reported the float bowl gaskets were wet with fuel and leaking slightly. That means the bowls were filling too much then. The fuel level was up to and soaking through the gasket. Now with them set @ 24mm, making the fuel level 3mm higher, the over-filling condition is causing the fuel to gush out. They're over-filling to way above the gasket now.
  3. davem222

    davem222 davem222

    That's a very good point. Couldn't it be that the floats themselves are deformed in some way? I mean, there's a lot of brass that can get angled etc from the float to the bridge, to the tang, no? Lol, is it possible that I have to replace every last thing in the carb? ha ha ha.....

    Either way 5twins, you are seriously the man, don't know where ya hail from but next time you're in LA, I'd like to buy you a beer.
  4. davem222

    davem222 davem222

    Hey! Guess who's a moron? Turns out, it's me. I was setting the float height with the things tipped so that the float tang was BARELY making contact w/ the float needle (just like I'm used to on my cb350). Then I watched lilbill's video and noticed that he did it w/ the carbs just flat upside down. Did it like that, set it to 24mm, no float gasket leaks, starts one kick with no throttle. BOOM. Long day of figurin' but the conclusion's the same as usual, there was something I didn't understand and/or was doing wrong. Thanks you guys for making it a one day process rather than a one month one :)

  5. MiniDanzig

    MiniDanzig XS650 Addict

    hey what video are you talking about? i've been having issues with my left carb leaking after cleaning. I believe i have set the float level correctly but still have leaking issues. I'd love to see this video.
  6. MiniDanzig

    MiniDanzig XS650 Addict

    oh whoops! found it. i searched "LilBill" like you said not realizing you meant "LittleBill".
  7. davem222

    davem222 davem222

    Whoops, yeah, littlebill, I just wrote lilbill as a joke :)


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