measuring float height on a VF500 Can someone explain it ?It's a mystery

Discussion in '1st & 2nd Generation 1983-1989' started by mandolinman, Oct 18, 2010.

  1. mandolinman

    mandolinman New Member

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    I have a vf500 49 states 1986. I put out a thread on cold startinbg earlier today.
    I figured I would check float levels .I consulted the Honda (grainy B&W )manual and the Clymer pics and description on measuring the float level and they show a honda tool in use. Specs call for 7.3 mm, but I cannot tell by the description or pics what or where or how you measure the float arm in relation to the carb body.
    With no hoda tool I made a 7.3 mm tools by taping multiple feeler blades and checking with a digital mike.

    The 7.3 mm tool cannot fit anywere under the float arm, so either my flats are 3 mm off of I am measuring wrong. Can anyone out there explain this mystery ?
     
    mandolinman, Oct 18, 2010


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  2. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    it measures from the sealing surface of the float bowl to the bottom of the float. you invert the whole carb assembly so the float is resting against the needles. Then measure from the flange on the carb where the float bowl gasket seals to what would be the bottom of the float if it were sitting upright like it would be mounted in the bike. This is measuring how the float would be setting when the bowl is full of fuel and shutting off the needle.
     
    Last edited: Oct 18, 2010
    tinkerinWstuff, Oct 18, 2010


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  3. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    by tweaking the float so that the measure number is smaller, you are "raising" the float when it's mounted in the bike and allowing more fuel in the bowl and resulting in a richer running condition.

    by tweaking the float so that the measured number is larger, you are "lowering" the float when it's mounted in the bike and allowing less fuel in the bowl and resulting in a leaner running condition.

    Generally, you should be able to just set the float to the factory spec and all adjustments to the running condition would be made by changing the jets, the jet needle, and/or the idle air mixture screw.
     
    Last edited: Oct 18, 2010
    tinkerinWstuff, Oct 18, 2010


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  4. mandolinman

    mandolinman New Member

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    wow that was quick. So the bowl rests in the needle?


    No way in the world I could have figured it out by BOTH manuals. Is there a special place in hell for manual writers? Ill probably be shaking hands with them after cussing and throwing tools around. Ill take the measurements and report back.
     
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  5. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    remember the needle is spring loaded. There is a spring loaded plunger in the back of the needle that the float rests against. make sure the plunger is free - sometimes old gas gums it up. And make sure the float is resting easy against the plunger, i.e., don't push down against the float messing up your measurement.
     
    tinkerinWstuff, Oct 18, 2010


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  6. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    actually, I think I misstyped above. The measurement is to the "bottom" of the float or the top when the carb assembly is inverted. Must edit my post above.

    I use a small adjustable square as a gauge when I do it.
     
    tinkerinWstuff, Oct 18, 2010


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  7. mandolinman

    mandolinman New Member

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    You used "smaller" measurement twice but i figured it out. The larger masurement equals a leaner mix...right?

    I will set to fatory spec and continue to tackle the cold start problem. The bike runs GREAT warm and at Op temp, but needs ether to start from dead cold.
     
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  8. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    yes

    The 3rd brass tube that is not removable is the pickup for the choke. it's a major pain to get the choke system cleaned out. Must use carb cleaner and probably compressed air (safety glasses). Air nozzle with a rubber tip is helpful when cleaning carbs. The brass tube connects with one of the passages that leads up to the top of the carb by the rubber vacuum slider diaphram.

    hard to describe but you'll know it when it's clear. work the choke plungers too. some people will use a carb cleaning straw, fill with fluid, and wedge it on the brass tube. if fluid drains from the straw and on all four carbs at the same rate, you're good.
     
    tinkerinWstuff, Oct 18, 2010


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  9. squirrelman

    squirrelman Member

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    IMG_0205 xx.jpg


    Float height gauge made from creditcard.....
     
    squirrelman, Oct 18, 2010


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  10. mandolinman

    mandolinman New Member

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    Thanks again I am tackling this today. Ill post the results.
     
    mandolinman, Oct 19, 2010


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  11. Michael E

    Michael E New Member

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    I thought that the description in the Clymer was very clear. The trick is to find the angle to tilt the carb so that there is sufficient gravity on the float to have contact with the plunger on the needle, but not too much that the plunger presses into the needle.

    I second TWS statement about checking to make sure that the plungers in the needles are not gummed up and that they move freely. A few of mine were gummed up.

    Lastly, unless a PO messed up the float adjustment, the floats heights should be fairly close to spec. If you find you are finding large measurement variances between actual and spec then you may be measuring incorrectly.
     
    Michael E, Oct 19, 2010


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  12. mandolinman

    mandolinman New Member

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    I used as .010 guitar string and brake cleaner and I finally punched through the varnish in the tubes after soaking overnight.

    All four tubes were clogged solid after sitting for 12 years.

    Thanks again!!
     
    mandolinman, Oct 19, 2010


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  13. Michael E

    Michael E New Member

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    Ernie Ball, Bullets or Dean Markley's?

    Congrats! That should make a difference.
     
    Michael E, Oct 19, 2010


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