Float height measurement question

[bmonnig]

Guys,
I've had a problem with fuel coming out of my overflow hoses while at a standstill on my '00 KDX 200. To hopefully fix this issue, I'm trying to set my floats with my dial calipers. How do I best measure the float, but avoid parallax (sp?) error? I'm trying to measure from the gasket area on the carb to the top of the float itself. Unfortunately, the floats on my 2000 are kind of trapezoidal shaped, as opposed to perfectly square. This doesn't give me much area at the top of the float (when carb is upside down) to look at. This makes it tough to make sure I'm flush with the gasket surface, but also exactly parallel with the top of the float (as opposed to looking at some slight angle).
It'd be much easier if I could measure to the mold lines on the floats themselves, but since each float is differently shaped, I'm not sure the mold lines are in the exact same spot.
I'm open to any advice on how to accurately measure the float height using my dial calipers. FWIW, I'm using the JustKDX spec of 16 mm +/- 1 mm as my goal.

Brandon

 

[MX175]

We may be able to save you a lot of time and aggravation. Don't start with measurements. Start by replacing you needle. Not the one that is in your slide and has a clip on the end. Change the one that is moved by the floats. It is more likely that it is not sealing against the seat correctly than something changed your float setting, See the last response (currently) in the thread listed as "following son". Member "canyncavr" does a great job of explaining the situation and the remedy. Keep your eyes out for his responses. They are always better than the rest. If you don't have a hearby dealer that has the correct needle, try www.sudco.com, www.carbparts.com, or any of the bigger internet dealers. Let us know how it works out.

Mark

 

[HOTRODKY428]

CAN YOU GET A NICE FLAT STRAIGHT EDGE ON IT, SUCH AS A THICK FEELER GAUGE ?

 

[JCW]

An easy way to check the float level in the bowl is to close the petcock and stop the fuel flow. Then, take out the screws on the bottom of the bowl and drain out the fuel in the bowl. Next, put the bowl back on the carb, but do not put the screws in it (hold it up tight with one hand) . Then, open the petcock and let the bowl full up. After you have given it enough time to fill up, close the petcock and carefully drop the bowl to see what the fuel level is. The other thing I would do is to clean out the "needle and seat" as MX175 mentioned above. It's easy to get a sandy crud up in there and create some opening and closing problems. Just a couple of ideas (from past similiar experience) Good Luck!

 

[bmonnig]

Guys,

     Thanks for the input.  I ended up using my calipers to get the readings.  I sighted along a straight edge of the caliper jaws to make sure I was parallel with the bottom of the float. 

     It turns out my floats were lightly tweaked.  One was higher than the other.  Using my calipers I was able to set them both at the exact same height, and set them to the 16mm +/- 1mm as specified.

     I also cleaned/wiped down the float needle, and cleaned out the needle seat with some q-tips.  No grit, but a fair amount of yellow varnish-like buildup came out.

     I'm not sure which adjustment did what, but the bike doesn't puke gas anymore.  Also, today the bike fired on the first kick (which hasn't happened in a while).   It's the first time I've fired the bike since doing the cleaning/adjustment.  Hopefully it'll stay! 

Brandon

 

[smb_racing]

here's an idea that might help you out, attach a piece of clear tubing (aquarium hose) to the drain on the bottom of the float bowl. Hold the open end of the tube up near the top of the carb body and turn loose the drain screw, the fuel will level out in the tube at the level it is in the bowl. From here you can base how you want to adjust.

 

[MX175]

WAY TO GO BMONNIG!!!!!!!

Isn't it a great feeling to know that you improved that bike yourself? It is fantastic to know that fuel is flowing smoothly through the needle and seat and that the floats are set to the right height.

A little confidence in your own ability goes along way, both riding the bike and in maintaining it.

 

[canyncarvr]

re: '...(when carb is upside down)'

Used to be standard practice to turn a carb upside down to check/measure/change float level. That was before 'they' (the proverbial THEY) started using spring pins in the needle.

If you turn the kdx (pwk) carb upside down to check the float level....you'll be off a good bit. Your fuel level will end up TOO low if you don't take the pin into account.

Yeah....it won't pee anymore. A/F mixture will be considerably leaner, too. Seeing as most kdxs are way to rich to start with, that alone may not be a bad thing.....but it's certainly not the way to fix an A/F mixture problem. You'll find yourself on the dunes at the coast one day with a piston glued to the cylinder!

Check CDave's site. He used to (I haven't checked recently) have a write up on a level checking device. Similar to what smb mentions.

You can use the float mold lines on the 'H' model kdx. Parallax is avoidable by keeping your line of sight perpendicular to the float body at the mold line.

Sounds more complicated than it is. Same procedure you use to measure anything.....you can't be lookin' sidewise at it!

I changed my '00 200 to 17mm for the express purpose of carburetal continence. It works fine 98% of the time. The other 2% is when the bike is so wonky on the stand that no reasonable float adjustment would matter.

If you didn't take the spring pin into account (this all brought on the the 'holding upside down' comment), you should recheck your float level. The measurement is taken as the float just touches the pin...not with the spring at all depressed.

BTW...the reason the floats were out of whack in the first place is likely due to less than required care used when replacing the fuel bowl. It's easy to tweak the float if you're not careful.

The bowl needs to 'swing' onto the body of the carb......kind'a like it's loosely hinged on the intake side.

Cheers!

 

[bmonnig]

Originally posted by canyncarvr  
If you turn the kdx (pwk) carb upside down to check the float level....you'll be off a good bit. Your fuel level will end up TOO low if you don't take the pin into account.

If you didn't take the spring pin into account (this all brought on the the 'holding upside down' comment), you should recheck your float level. The measurement is taken as the float just touches the pin...not with the spring at all depressed.

CC,

     As always, thanks for your input.  :worship:  I'm used to working on CV carbs on streetbikes, and the spring-pin is common there (I'm used to newish-sportbikes).  As such, when I measure/set the float height, it's not actually with the carbs upside down.  There's some degree of rotation that will put the float tang in contact with the needle pin, but without actually putting any of the float weight on the pin.  This is the point at which the float height is measured. 

You can use the float mold lines on the 'H' model kdx. Parallax is avoidable by keeping your line of sight perpendicular to the float body at the mold line.

     How can you use these mold lines?  Rather, what is the height of the mold lines from the gasket surface?  I realize it's 16mm +/- 1mm from the gasket surface to the bottom of the float, but how does that translate to the proper height for the mold lines?  Also, with each float being differently shaped, is the mold in the same spot on each float?  IE, can you accurately use the same "mold line height" for each float?  I'm not trying to be confrontational, I'm just wondering at the specs for using the mold lines.  Of course, if you're just trying to set the floats "parallel" using the mold lines, that's pretty easy to do.  ;)  

     As far a parallax, I agree with your comments.  The hard part is keeping the line of sight parallel!  The floats are dark, small surface (on the bottom), and it was hard for me to get good reference points for a steady measurement.  I ended up turning the calipers slightly, and "sighting" along the ID measurement pawls (on the calipers) to the bottom of the float.  Much like aiming a rifle using the top of the barrel.  It seems to have worked great for me.

Sounds more complicated than it is. Same procedure you use to measure anything.....you can't be lookin' sidewise at it!

     Sadly, I've repaired too many bikes where the owners seemed to be doing just that!  Well, assuming they took any measurements at all... :flame:  

I changed my '00 200 to 17mm for the express purpose of carburetal continence. It works fine 98% of the time. The other 2% is when the bike is so wonky on the stand that no reasonable float adjustment would matter.

    I too went on the + side of the measurement.  I've got them set at about 17 mm.  They were on the 15mm side initally, so I decided to go to the other end of the acceptable range to see the difference.  Working well so far!

BTW...the reason the floats were out of whack in the first place is likely due to less than required care used when replacing the fuel bowl. It's easy to tweak the float if you're not careful.

     Yeah, I know.  My fault.  :think:  I purchased the bike in Arkansas, and I live in Missouri (Lake of the Ozarks).  On the way home, my buddy in Springfield, MO wanted to ride with me on my "new" bike.  Of course, the KDX initially ran like crap.  Pulling the carb revealed all kinds of varnish and gunk in there.  It looks like the "less than 6 hours on my 2 year old bike" statement by the seller might be correct.  :scream:  A quickie carb clean (friend riding his bike around waiting on me) resulted in me tweaking the floats.          

The bowl needs to 'swing' onto the body of the carb......kind'a like it's loosely hinged on the intake side.

    Ayup.  See my "some angle that puts the tang in contact with the pin, without putting pressure on it" comment above.

Thanks again!

Brandon

 

[canyncarvr]

re: 'There's some degree of rotation that will put the float tang in contact with the needle pin, but without actually putting any of the float weight on the pin. This is the point at which the float height is measured. '

To each his own...but I'd have a hard time doing it that way. You end up with a freely moving float, the carb held at a wonky angle whilst you're trying to measure something with a caliper.

I hold the carb upside down, bowl flange horizontal. Then place my finner between the float and carb body to raise the float to where the tang just touches the pin. With the carb level, the float held in position it's easier to avoid parallax problems when measuring.

re: How can you use these mold lines? ...Of course, if you're just trying to set the floats "parallel" using the mold lines, that's pretty easy to do.

Guess I didn't wonder a whole lot at the process. I held the carb as noted, made the mold lines parallel, measured 16mm. While spot on spec wise, the point was to reduce peeing...not so much get to a particular number. I bent the tang such that the mold lines were off parallel to the tune of 'about' 1mm from the center of the float to the edge. Re-set the floats to again 'just' touch the tang to verify the 1mm slope. Done.

re: Sadly, I've repaired too many bikes where the owners seemed to be doing just that!

Well, sure! Fits with the 'moh tight is moh better' idea (as applied to fasteners).

Had no intention of impugning your methods. You get an idea of who knows what after awhile 'round here. You do. Great!

I have spent a fair amount of time trying to resolve somone's carb problems before......only to find that the AIR screw being referred to was black in color and plastic in nature.

oops.