Carb float adjustment

I know most like to use the clear tube method to get the floats just right.

I would love to see if anyone knows what measurement would get my XJs
Hitachi floats in the ball park.

Im working on a XS and ran across this on another forum.

 

17.5 +/0 0.5mm should get you in the ball park.

Measure in line with the main jet, just like the one in the picture. Instead of fully inverting the carburetors though angle them about 45 degrees so the weight of the float isn't depressing the spring in the needle.

 

is there a typo in that measurement? Im not familiar with +/0 0.5mm

 

I conduct a Clear Tube Test.
Odd are 4:1 you'll have one right on-the-money!
Maybe more than 1.
You need 1.

Measure THAT one.
THAT Height is where you need to set the one's that weren't right.
Go-ahead and do all of them to the optimum height.
Re-Clear-Hose Test.
If they're all GREEN or in the YELLOW.
You're done.

 

bend it DOWN or awayfrom the carb body to RAISE float level, bend it UP to LOWER fuel level.

 

He meant +/- 0.5mm. Plus or minus half a millimeter. Then you'll be "in the ballpark" but the clear tubing method will reveal any variations.

A tip: "Bend" is too harsh of a term; what you have to do is "nudge" the tang; if you bend it enough to know you bent it, you probably went too far. Gotta be real gentle and careful or you'll drive yourself nuts.

 

Thanks for the clarification Fitz.

 

17.5mm (+/-) 0.5 mm

Plus or Minus.

You can make a handy Tool out of an Expired Credit Card.
Using a Protractor, ... Scribe a Corner "Square"
Cut the End off making one end a PERFECT 90-Degree Angle.
From the Squared Bottom, ... Measure up 17.5 mm
Scribe a Squared Line across the Card at the 17.5 mm mark.
From the Side which is Square without rounded corners ...
Measure IN ... 1.0 mm at the Bottom and Top.
Scribe a Line from Top to Bottom 1.0 mm wide.
From the 17.5 mm mark, ... add 1.0 mm's and scribe a line above the 17.5 mm Mark.

Remove the Plastic within the Right Angle and the portion above the Upper Line.

What remains is a Measuring Tool which will indicate 17.5 mm's Height above the Carb Body Base where the Gasket seats.

Remove the Gasket.
Place the Float Height Square on the Base.
The Highest part of the Float should be at the represented Height.

 

Right. And that gives you the dry setting, your starting point for the float adjustments.

The you gotta check 'em wet.

 

Thanks guys, you think that badazz penetrating oil will loosen up my stripped bowl screws enough?
I have ONE bowl screw that will come out.

 

as ever Fitz speaks truth about how gently to apply force to the float tang.
I'm the sort that has to establish mnemonic devices to remember things and establish muscle memory to get common tasks optimized and done right repeatedly. Otherwise I take for ever planning just the right way to do a very simple task each time.

My technique for adjusting carb float tangs is this. First as Rick said, check to see that it actually needs adjusting. If it does, with the float out start by bending it with fingers or CARFEULLY with needle nose pliers (nylon tip prefered) Always toward the needle. Adjust it by eye about 10 degrees further than you think it will need. Then reinstall the float. This should have the level say WAY too low. On every carb I've played with, push on the floats gently until they bottom out against the inside of the carb body. This will bend the tang back (raising float level) and get very close to the correct setting. Install the bowls with two screws on opposite corners finger tight. Install the carbs on the bike. Do a tube test.
Removing the bowls is easy with just two screws finger tight. The level should be set a bit low at this point so raising it is easy. just apply a BIT of pressure on the float arm "springing" it up but not NEAR enough to deflect the arm itself. Each time will deflect the tang a bit, raising the float level.
Tweak, install bowls, tube check, repeat. It's pretty dang easy.

If you can find a way to fixture it carefully and securely I would use the tappy with the hammer type impact driver. pen oil is good but the problem is the steel screw in gummy cast aluminum threads. If it weren't for the gas fumes from the carbs themselves I'd recommend heat. That and I dunno if you plan on reusing that gasket.

Anybody got a line on that cold shot pen lube? Supposed to spray on the bolt to shrink it. Kinda like taking a torch to the threaded piece.
Used it? does it work? any clue what I'm on about?

 

Ahem. Gentlemen all:

setting fuel levels

Good to have another excuse to post that link... Len and I slaved over the file for what seemed like forever. :mrgreen:

 

Wow! Nice write up!

 

To loosen and extract stuck fasteners you need to have a Hand-Held Impact Tool.
One of the MOST Important Tools needed for maintaining these Bikes.

http://www.craftsman.com/shc/s/p_10155_ ... =0&prop17=

You add:
1/2 -to- 3/8ths In Drive Impact Adapter
3/8ths Universal Bit Socket.

Use the Impact Driver to loosen the Stuck Fasteners.

Also: Locking Needle Nosed (Vice Grips)

http://www.craftsman.com/shc/s/p_10155_ ... ockType=L4

Having the right Tools when you embark on a project (( Especially, ... Carburetors )) will save time and aggravation.
Plus: Using the wrong Tools will likely cause you to suffer setbacks from causing damage to the Fittings, Screws and Jets needed to be removed, ... possibly ruining them.

 

I will buy the impact tool but I am not comfortable using it on the carb bowls. That little chunk of 30 y/o aluminum might not make it out alive it Im warping on it with a hammer and impact tool.
Ill just drill and easy out. http://www.google.com/products/catalog? ... ps-sellers

 

Foolproof, damage free way to free stuck drain screws:

Screw the floatbowl tightly to a scrap of lumber, using appropriately-sized screws in all 4 holes. (Mounting the float bowl gives you a good way to firmly hold it while off the carb.)

GENTLY apply heat to the floatbowl, not the screw, in the drain area (around the screw.) DO not heat it red hot, just get it good and warm.

Apply Kroil. (Optional, the heat will usually do it alone.)

Unscrew the screw.

I have personally used this method with great success on more than one occasion.

 

Hey fitz, are you talking open flame for heating or one of tose electric type used for paint stripping?

 

I've always done it with a propane torch. I'd think a heat gun would work too.

 

MiCarl, not sure what those electric guns get up to, but do know "Pretty damn hot" is what I've found out!
Might be hot enough to loosen stuff, but not the danger of melting with an open flame.

 

aluminum don't turn red, it just melts

 

True. Fortunately it's difficult to get it that hot with a hardware store propane torch.

I always quit when the wood block starts to smoke. :wink:

 

Me too. Never actually tried to melt one.

However, I've also never tried using a heat gun. I think I'll experiment with that next time (see if I can get the block of wood to smoke.)

 

A brief look at the Harbor Freight site shows the two models they have listed are rated for a max temp of about 1100F -- which a google search shows is about 100F below the melting point of aluminum. TMYK.

 

Wow, if that's what they heat up to then there would be more than enough heat to break things loose with the added benefit of your float bowls not turning into a puddle!

 

Yeah, I confirmed that all the floats were ok via clear tube method today.
Does anyone know what would make gas go into the oil BESIDES a messed up auto petcock?
I tried to run a new thread on this but was told to put a on/off valve from a briggs and stratton mower on the fuel line. I have a NEW manual petcock and I turn it off like clock work.

Thanks for you help in advance.

 

Not sure, but when I rebuilt my bowls, I had one float that would pass the clear tube test, but when I held the carbs upside down, it wouldn't always come back down when inverted, needed a nudge, which i would translate as bad news when riding. It ended up being a slightly warped float pin the made it bind a little when swinging on the pin. Can't imagine anything else that could cause it. Could it be getting past your rings in a cylinder maybe?

 

With the manual shut off you've eliminated the 1st source of the problem, so the only other cause would be that the float needle is allowing fuel in the bowls to get by, which would lead me to believe that the bowls are too full. When riding the bike it's not a big issue, but when parked, even with the petcock shut off there may be enough gas in the bowls and the line to allow it to seep down and contaminate the oil.
The only solution, if that's the case would be to shut off the gas and then run the bike till it dies of fuel starvation, which probably is not the most convenient thing to do every time you pull over for an extended period of time.

 

If you are going to use a Manual Petcock, ... you'd be doing yourself a good turn to have "Spring-loaded -- Viton-tipped" Float Needles.

 

^^^^^ going to look for it now.

 

speaking of float levels, I just finished doing the full rebuild and after many attemps at getting the bench levels set, I installed and bike ran great...then out of nowhere the drain tubes on two I had to adjust started pouring fuel out....is there any other cause? damn I can rebuild a carb no problem but float levels giving me a fit! got to pull everything down again!!

Just frustrating..for what should be the easy part!

 

You have to mount the rack in a fixture of your choice so that it's level front to back and side to side, and set the float levels using the "clear tube method" and fuel from an auxiliary source.

Dry setting them won't do it; from the sound of things you have one or more adjusted way too high or hanging up for some reason.

 

Measure the Height of Floats from the Base WITHOUT the Gasket using the "Clear Tube Method"

Find the ONE (or more) that is closest to this Illustration:



MEASURE the Height of the BEST one found to be within these Specs.
SET the OTHERS to the Height of the ONE that you have on-the money.

 

Rick that's what I used, not my first time around the block either...but for some reason it just is testinig me. I made no less than 5 test rounds but these last two just seem to not react like I'm expecting....not sure if its the tube I'm using thowing me off or not...but its a kick in the butt to think your almost finished, button things up only to get kicked to the back of the line.

So its back to pulling them down again, check these things out...measure and then reset..then I'll be done.

 

Gator, I havn't read all the posts, but it would seem your float needles are letting by.

 

Agreed m8...just the trials and tribulations, its one of those things...you know what's right and still something goes wrong. This next go around I will spend a bit more time making sure the carbs are indeed level, I may have in fact been off a bit..which is enough to create the situation...like a lot of things we get a setback then havve to try again.

Cheers.

 

I have also seen both new and "old / dry" needles change levels after soaking in fresh gas for a couple days OR being opened/closed a couple hundred times during the coarse of riding.

There is really not too much you can do but reset them and monitor until you get some riding time in. Excercise those needles guys

 

Hey Rick, I Googled the "Spring-loaded -- Viton-tipped" Float Needles and only came up with three hits, one of which is quoting you in this thread. 8)
Do you have a link or is this something that Len sells?

 

I honestly didn't think about that..might explain how it was so right on the bench..then an hour later was so wrong...anyway no worries..just more time...really just wanted to vent...I just felt I was good and done with it.

 

My float needles do have a wear ring from where they seat.
The new needles I bought didn't seem long enough so passed
on replacing them at the time. Guess I'll be talking to Len.

 

You SHOULD be able to use the shorter ones but will need to re-set everything AGAIN.

You can "resurface" the needle seat by using a golf tee in a drill and polishing the seat where the needle rests. The wood is just hard enough to polish up the end and take any corrosion off and it will modify the seat ever so slightly to give you a little different sealing spot on the tip of the needle. Doesn't always work but it doesn't cost much to try.

I also like to use a tip polishing bob for a dremel on the seat of the petcock plunger also. That seat needs to be perfect so the oring has half a chance of sealing it shut since there is a fairly weak spring closing it. Many a new kit has failed because the petcock body had some corrosion there to keep it from sealing.

 

I went with replacing everything but the floats themselves...odd bit I checked the outside one with it on the bike and it still shows its at the right level...so I'm not sure what's going on...I will double check tonight to make sure of which ones were flowing out the vent tube...now I'm starting to wonder.

I am curious if you ran the bike with the petcock in prime mode would this create an over flow problem? My understanding is that it shouldn't, but I could be thinking wrong.

 

You're correct; leaving it in PRI shouldn't cause a problem as long as the floats are operating correctly.

The best way to check/adjust the floats is with the rack off and "mounted" so that it is perfectly level front to back and side to side. Some folks build a rack, I use my bench vise. Then you can not only check the levels, you can test the operation of all of them. Every carb needs to be verified individually.