float height setting.

i've been searching and searching and no one has a clear answer other then the 3mm fuel level setting. which is a complete waste of time in setting the carbs. that might tell y ou what the fuel level is. which is all fine and dandy, but i don't want to be taking the bowls off OVER AND OVER before i finally acheive that magical fuel level.

IN THE OLD DAYS. THERE WAS ALWAYS A FLOAT SETTING. THIS FUEL LEVEL THING DIDN'T EXIST UNTILL NOW.

so, can anyone give me an answer as to what the float height should be. that's with the carbs upside down. checking the floats at the base of the carb WITHOUT the gasket.

dealer says 18mm WITH the gasket. but your lucky if the bike runs as there won't be enough fuel in the bowl. i've tried 16 as suggested by another post not on this sight. then i've also tried 14.

the local repair shop says he always adjusts the floats level with the base. which takes the floats to about 8 or 9. everytime i go with the level base height i overflow.


IS THERE ANYONE OUT THERE THAT CAN GIVE ME AN EXACT ANSWER SO I CAN GET MY CARBS SET. instead of screwing around trying different things. . it would be greatly appreciated.

 

The correct "float height" is whatever float height results in the proper fuel level in the bowls.........no two ways around it.

The proper fuel level is actually published in every Yamaha service manual for these bikes, ever since the beginning of time for these bikes. The float height necessary to achieve such fuel level was published in a few early editions of the service manuals, and then dropped, and probably for good reasons (it leads to errors).

The fuel level in the bowl is the actual "goal" you are shooting for. For example, there are no less than three (3)---and probably more---versions of the Hitachi float valve seats and needles available (made by different OEM manufacturers). These needles differ in overall heights, as do the depth of the float valve bores where the needle fits. I will guarantee you that using float valve style "A" will result in a different fuel level in the bowl than when using float valve style "B" if they are both set at the same "float height".

And that's probably why Yamaha stopped publishing "float heights", because they or their carb suppliers were using different types of float valve components as time went on, and thus while the required fuel level never changes (for a given type of carb/engine combo), the float height needed to achieve such a fuel level did change as different components were installed.........

 

i hear what your saying. but i'm old fashioned and i need a float height. i don't want to screw around with sticking some type of tube in the drain hole. filling it up. then have to drain it. disassemble the carbs. make the adjustment. reassemble and check again. that's A LOT OF WORK.

i want to adjust the float and be done. just like i've been doing for 25 years. the float height specs ALWAYS worked for me. cuz right now. i'm screwing around with things i shouldn't have to be screwing around with if i had the damn specs to begin with. i've taken the carbs apart 10 times now to follow up on everyone's suggestion. and the only thing i can't find is the float height.

maybe if someone has the book that was published back in 1984 where it still had a float height.

the dealer says 18 with the gasket. someone on the internet says 16. the repair shop says level with the base. who's right and who's wrong.

 

I understand that the proper float height is 17.5 mm, however I am always confused as to where the point of measurement is taken. I have been using the float at the highest point measured with a caliper to the "deck" of the carb body. Of course the carb is upside down. This has worked to get the bike started.

 

Snowwy, I would recommend that you set one carb to the proper fuel level (via tinkering, draining, etc.) and then measure the float height on that carb, once it's achieving the proper fuel level.

Then you can use that known "good" float height as a basis for setting the other three carbs, using whatever measuring points you used on that first carb.

Then, of course, check the other three to make sure that their fuel levels are okay.


That's about the easiest "shortcut" there is to achieving the proper fuel levels!

 

Here is the link I was looking for earlier :

http://xjbikes.com/Forums/viewtopic/t=9 ... eight.html

 

It's sounds like the tab bending is what's really getting you confused. Try this. Do your clear tube measurement. Note how far one way or the other you are from spec.

Take the float bowl off. Measure from the middle of the float (I think the middle would result in 1-to-1 ratio of wet to dry float height difference) to the to what ever reference point you want on the carb body...like gasket surface. Then take the float off, bend the tang, put the float back on, and compare the difference to your previously measured float height. You want to make the difference equal to the amount you were off with your clear tube measurement.

Then put the bowl back on and find your clear tube measurement. Use gas...not some other fluid. All but one of mine worked with the 17.5mm setting from the gasket surface...but like chacal said...that's not good enough. Remember to keep oriented which way is up or down when you are going from the clear tube spec difference to your dry height difference.

Also, you could try getting one float "right" wet, then measure the float height dry and make the others match. Still double check using the clear tube method...of course!

 

That height is for the HSC32 (Hitachi) carburetors used on the XJ650 and XJ750. I am the peddler of that value and I obtained it from the "Service Data" section of the old Yamaha fiche which seems to no longer be available.

Since it was just a number in a table there was no information on how to measure it. I've always measured to the bottom of the float at along the plane of the jet needle. I've never had to pull one off and redo it using that method.

You need to make sure that the weight of the floats does not depress the spring plunger in the needle or the measurement will be off. You can achieve that by holding the carburetor bodies at an angle rather than straight up and down.

All the manufacturers went from float levels to fuel heights in the early 80s (so it's not really a new thing). This is about the same time they started capping the mixture screws on street motorcycles. I think prior to that they let motorcycles run a bit rich so precision wasn't an issue. When emissions regulations started to catch them they had to get the mixture on the knife edge where the engine would run well without polluting too much - requiring much more precise measurements.

snowwy66 - you did not include your motorcycle model in your question. If you don't have HSC32 carburetors this information is useless to you. Perhaps you should add motorcycle specifics to your signature.

 

i don't kow what the carbs are. whatever the book says. they are stock carbs is all i know. 81 xj650

17.5 mm is a bit lean. the dealer says 18 with the gasket and the bike wouldn't run. i went 16 from the base WITHOUT the gasket. that's 15 WITH the gasket. measure at the highest point on BOTH floats. i measure all 8 floats. not just 4. becuase they might get bent OR the tang might not be straight. so one float measures different then the other float.


i lift the float off the needle and tweak the tang with a screwdriver on both sides. then i grab needle nose pliers. and gently grab the little clip on the needle and lift the float and release the pliers. then i measure both floats.

being a retired car mechanic. that is how it's done adjusting the floats on car carburetors. when cars used to have carbs.

anyways, i had a clear tube i was able to screw into the drain hole enough to check fuel level without leakage. looks like i'm about 4mm from the base. so 15 - 16mm is the float height. measured at the base without the gasket to the highest point on the float.

EDIT: I'LL BE A MONKEYS BUTT. i just looked at the manual and just NOW noticed the float setting at 17.5mm +/- .05mm. doesn't say anything about the gasket though.

 

I used 17.5 to start, but that was a bit low. Went to 17mm float height and got exactly 3mm fuel height.

 

Ther should be a cast fuel "nipple" on each carb bowl that you insert the clear fuel tube over.....that nipple is where the fuel flows when the drain screw is loosened (you would loosen the drain screw for performing a fuel level check, or just for draining the bowls for winter storage purposes, etc.)

 

only fuel i get coming out is the drain screw. i never paid attention to that nipple when i had the bowls off. but i'm looking at some pics so i see what your talking about. it might even be plugged for all i know

anyways. i've got 9500 rpm revs now at stand still. 8000 was my max before. wasn't seeing any black smoke on the max revs either. all 8 floats are now set between 17.5 and 18. so we'll take her out and see what she does another day when it's not raining.

don't see my problem being fixed though. but hopefully now i won't have to deal with the carbs anymore.

 

HAHAHA...those are famous last words if I ever saw 'em...Your intake and exhaust are bone stock right?

Good to hear you are doing better.

 

exhaust is stock. the intake is oem replacement. shouldnt' have to take the carbs apart anymore now that i have everything in check. but who knows. once it's ridden. LOL.

 

sorry, im still confused! Am I supposed to measure like this? If so, my float level was way off! This is with the gasket off

 

Did you measure your float height using the clear tube method? That is the preferred method. If you did and found you were off, there is a link earlier in the thread were Bill measured from the gasket surface to the "back" of the floats. You have to angle the floats so they "just" rest on the needle and do not push it down. You measurement looks like the float is pushing down on the needle, and it looks like you caliper is too.

 

Just a clarification.........you don't measure the "float height" via the clear-tube method, you measure the FUEL LEVEL via the clear tube method.

The float "height" will determine the fuel level in the bowl.

And it's not just the preferred method, it is the ONLY method for properly determining the fuel LEVEL, which is the end goal of the entire process. There is some unique float height that will acheive the proper fuel level, but that actual height will vary between different carbs, different models, different years.......etc. Without measuring the fuel level in the bowl, the proper "float height" is unknown and unknowable.

As will the proper fuel level.........it, too, differs between different model carbs, different year bikes, etc.

Proper Fuel Level.........that's the end goal!

So always start there......measure the fuel level in the bowl via the clear-tube method, and then adjust the float height (via bending the little tang arm on the float).

Yes, it's messy, but your carbs will thank you!

 

i'll take float height anyday. screw that fuel level shit. i'm not taking apart the carbs to clean em up. AND HOPE the damn fuel level is correct.

ONE TIME. clean em up. set the floats. AND BE DONE WITH IT. as long as it runs close to specs. that's all i care. your never going to get a 30 year old machine to perform like it was brand new anyways.

and that's my $5 worth.

 

They actually run BETTER than brand new, now that they are broken in and adjusted a bit richer than "factory".

 

running rich don't make it run better. that's a myth. it just pollutes the atmosphere more.

your heart don't run better with age. your motorcycle don't run better with miles.

back in the day when i had my 82 brand new and i was still a mechanic. i did every adjustment there was and checked with an emissions machine.

THERE WAS ABSOLUTLY NO EFFECT ON PERFORMANCE. you either had a high hydrocarbons (unburned fuel-too lean) or high carbon monoxide (partial burned fuel-too rich). horsepower was still the same. give or take a horse

 

snowwy, the wheel has been invented, don't screw with it.

 

Ok, ill do the clear tube test and see where im at. So I put the petcock on PRIME, and then attach the tube and measure the height from the bottom of the carb up along the float bowl wall right?
Do I keep it on PRIME the whole time? Or do I turn it back onto ON right before i open up the drain screw?
Do you do the test with the carbs on the bike?
Is it possible to reach all the drain screws with the carbs on?
Thanks alot!

 

I've never done it with the carbs on the bike, but I 'spose it can be done, I like to do them on the bench in a more scientific way, 'cos ther can be a lot of on & offing of float bowls & I like to have a clear constant flow of fuel.

 

When you measure the float height you are measuring the heght as if the gloat bowls were full, and the gas was shut off right, with the float at its maximum height right??

 

Not quite. The float is at it's maximum height WITHOUT compressing the spring loaded plunger in the float needle. That's why it's best to not completely invert the carburetors when measuring. 45 degrees or so should be sufficient without the weight of the float compressing the spring.

 

the carbs need to be completly upside down. the floats HAVE to be resting on the needle. COMPLETELY and with there own weight in order to get the proper float height.

when the carbs are mounted and filled up with gas. they don't sit at a 45 degree angle.

you want to know EXACTLY where the floats are going to be positioned when the bowl gets full and needs to shut the gas off.

 

Very highly paid and experienced engineering, operational, and technical design folks at the Hitachi and Mikuni corporations---the people who manufactured these carbs---- would dis-agree with you Snowwy.........

These aren't Rochester Quadrabogs or Carter Thermoquad carbs. They aren't even Holley R-2975A tri-power carbs.

You should follow the maintenance procedures and recommendations that are specific to different manufacturers products. Not a good idea to use a Toyota service manual to tune up a Buick, that's all I'm saying.......

 

snowwy66 - this is why the clear tube method of measuring FLUID LEVEL (got it right that time chacal :lol: ) is the only way to insure your floats are set right. In order for the float needle to seal on the float seat, the pressure on the needle from the buoyant force of the float in the fluid must equal or be greater than the pressure from the hydro static force of the fuel being pulled down by gravity. The bottom of the needle (when oriented on the carbs) is also spring loaded. Figuring out exactly where that equilibrium point is, measuring it, and testing it is more work than just filling the carbs with gas and measuring. But given the amount of volume that the float displaces, and the area of the needle tip, I would argue that the buoyant force that seals is MUCH LESS than the weight of the float.

And all my blathering means nothing if the needle doesn't seat well.

 

This is almost, but not completely, 100% incorrect. It's a pretty strong statement from someone who cannot seem to get his float levels correctly set.

In many cases the weight of the float assembly will depress the spring loaded plunger in the needle causing the float to move beyond the point where fuel flow would stop. The floats need to be resting on the needle but not compressing the spring. Perhaps this is why you continue to get unacceptable results?

This picture is a different carburetor, but the principle is the same. You want it rotated just enough so the float closes the needle, not completely inverted:



Even after setting the floats "dry" you need to use the clear tube method discussed by others to check and fine tune the results. The dry height should get you in the ballpark but as they have been saying you won't really know what's going on until you view the actual fuel level.

 

It would be the fuel pressure ( 1/3 of a PSI) divided by the area of the Viton tip, (let's say 1/8 th inch diameter for easy math),
1/16 X 1/16 X PI X 1/3 = 0.004 Pounds of seat pressure.
Or six hundreths of an OZ.

 

After reading all the arguments about what is the best way to set the float in this thread. I have to chime in and say... The bike DOES NOT CARE how high the floats sit. All it cares about is ..... Does it have the CORRECT amount of fuel at all times in each bowl. If for some reason one float isn't as buoyant as the others, the level will be higher in that carb than all the others. Causing THAT cylinder to run richer than the rest.. in most cases.

I would say, "spend the extra time to do a clear tube "check" and save yourself a lot of headache".

 

how are the float levels incorrectly set? becuase i have 3 different settings. and when i take them back off. the settings don't change.

the only thing not correct is not having the proper information in the first place.

one repair shop says level. one guy says 14. one guy says 16. and the dealer says 18 WITH the gasket. the book says 17 but no mention of the gasket. kinda hard to do the job with conflicting information. DON'T YOU THINK? specailly since i didn't have the book to begin with when i first started this fix.

doesn't matter if it's a mikuni or a rochester. i use the EXACT same procedure. been doing for 25 years and never had a problem yet untill now. this is the first time i've ever heard of fuel level.

and the bikes i've had previously also came with repair manuals from the previous owners. never heard the term fuel level untill i found this forum.

i'm not saying the fuel level is wrong. all i'm saying is i want float. not fuel. i want to do the job once. not over and over.

you guys do it the hard way.

i'll do it the way i've been doing it over and over all these years. and i'll do the job only once. as long as i have the specs. doesn't mean i wont' check the fuel level. but if the book calls for a certain number. well, i'm not one to argue with the book. becuase the book in mechanic terms is called the holy bible.

the only time i do over and over is when i'm changing things around. such as different jets or throttle needle settings.

we all have different ways of doing things. how long we all take to accomplish the same feat is a different story.

the fuel level is a good way to make sure everything is correct. but i'm not one to go by trial and error adjusting the floats to get that magical 3mm +/-1mm setting. that's an all day job for a job that only pays 1 hour.

 

If doing it by measurement, dry, worked, snowwy, we would all do it that way, but it don't, I have done it loads of times, acurate measurment, then test with fuel & they are all over the place, like a mad woman p------.
Just do it your way & don't worry about us idiots.

 

Good lord. The derp factor on this site as of late is spiking. First Rick and Bunglejyme get all bent out of shape when each has the unmitigated GALL to dare question the other's method for tightening nuts for the steering head bearings, then Snowwwy here has declared himself to be the King of Carbs and we should all ph34r his 1337 mad skillz, dawg.

Snow, you say set the float levels and the fuel level be damned, because that's what the "holy bible" says. I checked two sources -- the Haynes book, which by your reasoning should be considered blasphemous and obscene because it isn't factory issue, and the XJCD version of the 650G/H service manual.

The Haynes book does indeed list a float height of 17.5mm, +/- .5mm.

THE FACTORY MANUAL HAS NO FLOAT HEIGHT LISTING. It only lists a fuel height level of 3mm +/- 1mm "from the carburetor mixing body chamber edge." And what, pray tell, are we to do if the fuel level is not within spec?

"6. If the fuel level is incorrect, remove the carburetor assembly from the motorcycle and check the fuel valve(s) and float assembly(s) for damage.

7. If no damage is found, correct the fuel level by slightly bending the float arm tang. Recheck the fuel level."

Let's pull up page 126 of the Haynes book. Section 8, Carburettors -- checking the fuel level.

Subsection 5: "If any of the fuel levels are outside the above limits it will be necessary to dismantle the affected carburettors to establish the cause of the problem. Check for float damage or leaks as described in Section 6 and renew the float as necessary. Do not omit to examine the float needle and seat since wear in those components will affect the fuel level. If no sign of wear or damage is discovered, adjust the float height setting by judicious bending of the small tang which bears upon the float needle."

To summarize: both reference documents say to measure the fuel level, and bend the tang holding the float needle if necessary to bring the fuel level to within spec. We're doing it the "hard way"? We're bloody well doing it how the book tells us to. If you have a problem with that, go talk to Yamaha.

There. That should settle the issue. Can I get an "Amen!", y'all?

 

Nothings more exciting than a wobbly card table, blocks of wood, duct tape on a MT Dew bottle, and small cardboard boxes ( with a Georgia return address) holding clean carbs and 4 clear tubes, while an ancient boom box with 1 speaker blasts out hard rock late into the night. . .

AMEN !!

 

I always thought knee dragging and sliding through the twisties was pretty exiting!

But since I've got the carbies off and ready for a bit of a tweak when I get home I must be in for an adrenalin blast!

Oooh, I can't wait :lol:

 

I'll give you an AMEN on that.

We adjust. And since it's hard to adjust in midair, we use a basic "dry" setting to get us in the ballpark. IN THE BALLPARK. Why?

-Because the blasted finicky CV carbs are also very finicky about the fuel level in their float bowls, and the fuel needs to be at the correct level. THE FUEL. The whole reason for the floats to begin with.

The bottom line is this: if you adjust using dry measurements only, you may very well get it quite close; and possibly close enough to work ok. However; if you have ONE "abberant" float that produces a fuel level way too high or way too low, you will then drive yourself crazy trying to tune the carbs.

Why? Because a carb with too much or too little fuel in the bowl will not perform correctly, period.

You can adjust away all day with the "dry" settings, and never REALLY know what results you're getting, fuel level wise. And that's what we're trying to adjust. Using the clear tube allows us to monitor (and hopefully validate) the results of our adjustment efforts.

It's simple physical science; we don't just make stuff up. What amazes me is the amount of effort people will put into rationalizing a "shortcut" because the real procedure seems difficult or to them, unnecessary.

 

Didn't think I'd ever chime in on this one, but I'm gonna break it up a little. Let's say each carbs fuel level is different but all within the tolerance, does that affect the position of the mixture screw when fine tuning from one carb to another?

 

-all the carbs fuel levels WILL be slightly different, even within tolerances (which aren't very "wide.")

-the mixture screw we adjust is just for idle; but it does affect the rest of the range. I don't know if the minor variations between in-spec float levels would cause enough of a difference to affect idle mixture drastically, but in theory it would do so, at least slightly.

It's when you get one that's too high puking fuel all the time causing an unadjustable rich condition, or one that's way too low causing constant starvation, that it throws everything off.

 

Great thread!
Loved the point/counter point.

1) a single float height for all floats will give a gen performance range. thats it. Why? because there not 100% exactly the same float. nor are the springs and needles, etc a 100% perfect match. So......If you want fine
tuning, each floats height must allow for the correct fuel height within
a particular bowl. That means a slightly diff level for each float unless
your' very lucky and the settings you have put you in the zone.

2) Unless there is a prob with performance, this type of fine tune is
prob overkill for the avg rider. So the same float height may very
well work well enough for some. AS far as I know mine have never
been changed since the factory and I've had the carbs apart many
times. I would however most likley follow the advice of our experts
on this site as they have more exp with these particular carbs then
the guys at the "stealerships.

<edit> my bike runs great lol.

 

1. Exactly.

2. No, this isn't "fine tuning," it's a "basic setting." It's not something that should change; it's a "set it and forget it" type adjustment. ADJUSTMENT is generally only necessary if you have changed anything, replaced parts, etc. This is why the service manuals have you use the clear-tube method, ON the bike: Just to confirm and ensure that nothing has changed or is malfunctioning.

As long as all 4 carbs have fuel levels within spec, and a tight spec it is, then having them EXACTLY the same isn't necessary; the spec is tight enough to make it nearly a moot point.

But they DO need to be in spec to work correctly.

 

Since no one has mentioned the PHYSICAL affect of fuel level, let me. The level of the fluid in the bowl creates hydrostatic pressure that helps PUSH fuel through the jet and into the venturi. The emulsion tube has a negative pressure relative to atmosphere (Bernoulli's principle) because the fluid in the venturi is moving. So the total pressure gradient in the emulsion tube is going to be the DIFFERENCE between the Hydrostatic pressure of the fuel level in the float bowl, and the low pressure through the veturi.

Therefore, a greater float height PUSHES on the fuel more, resulting in more fuel in the venturi for a given velocity (and these are Constant Velocity-CV carbs) and a richer mixture. A lower fuel height pushes less. According to one of the links chacal provides to fine tuning carbs for mods, the fuel level can actually be used to fine tune the carbs from 2k-3k rpm (http://www.factorypro.com/ -> Product Support/Technical Support -> Motorcycle Tuning Tech -> CV Carb Tuning -> High RPM Engines)

Not that I've done the above...but I'm sure it would be worth it if you wanted to eek every last ounce of performance through every RPM range. But you should realize that the Clear Tube Fuel Level spec is really a pressure gradient spec that ensures the right amount of fuel is being drawn up though the main jet. It's just far easier to measure the height of a fluid column than it is to put a pitot probe in the emulsion tube.

Another thing to consider. There is all this effort to level the carbs (and I did it too) but I noticed the Haynes manual has you measure the fuel level on the BIKE (tilted forward, but level side to side of course) against the SIDE of the carb assembly, in the middle, not the back. Why? because that is where the main jet and emulsion tube is...right smack in the middle of the bowl. The height of the fuel level in the middle of the bowl will always be constant no matter how the bike is leaned, or how the carbs are tilted. Just thought that was interesting.

 

Couldn't have said it better myself!

Just another point of reference...When I did mine this past winter, I set with a 17.5mm dry height and then checked them by clear tube method. All were within 3 +/- 1mm so, I put them back in the bike. Never worried about them all being within a gnat's a$$ and have not had any performance issues from one extreme of the power band to the other. Bottom line, set them and verify by clear tube method. If they are within spec, the only thing extra that you did was to verify fuel level. This extra step takes all of 15 minutes once the carbs are level and hooked up to your fuel source. Skip it, maybe you'll get lucky, maybe not... your choice.

 

I just googled float levels for our XJs and found this link, I think it's hilarious.

I was scratching my head last night after cleaning my carbs, wondering how I'm going to adjust the carbs. I thought there would be an adjustable stop screw or something.

Does someone have a nice picture with a big arrow of what the fuel level measures from on the carbs?

On unrelated note, isn't computer-controlled fuel injection an amazing thing?

 

Try this:

http://www.xj4ever.com/setting%20fuel%20levels.pdf

 

One of these floats is not like the others... #2 maybe?

 

Wow. I am in the middle of cleaning carbs now and wanted to know where the float height measurement should be taken (because doing so was normal practice). Search brought me here.

I think Snowwy's original post shouldnt have attracted so much negative attention. All Snowwy wanted was the float height values and where to measure from. This was so Snowwy could get the floats as close as possible before he got to the point of checking fuel level. Why was this such a tough request?

Snowwy wanted to avoid putting the carbs together without setting height, putting them on the bike, measure fuel level, removing carbs, transferring measurement to the float, assembling, only to find he has to take them apart again. This is understandable. It wasnt Snowwy being lazy and trying to take a shortcut as some of you accused.

I want to set float height to spec., assemble carbs, and then check fuel level because this is the normal procedure. Chances are is that fuel level is going to be within spec at this point. If any are not in spec at this point then it will likely be a minor adjustment to one or two floats or a clear indication of a leaky float or bad valve seal. (I've seen a binding float pivot as an issue once)

Snowwy wasnt incorrect in his approach and I believe alot of you were incorrect with your responses to it. The issue that brought me here was one mentioned earlier except in a different context. The Haynes doesnt have the procedure on setting the float height. While this is true, to state that it is because it is worthless is a blind understatement. Maybe its not in the Haynes because they didnt have the measuring points information at the time of publishing or some other unknown reason!

On that note, the float height spec. given in the Haynes wasn't pulled out of thin air or made up by Haynes. A float height spec has all design elements, engineering, and variations accounted for including but not limited to the manufacturing variation in float buoyancy. Even regardless of different size aftermarket parts such as needle valves the float height spec will stay the same. It is not a ballpark figure. From my own experience and information found around the net, it is the standard starting point and one that I have found to be used as a common starting point to setting heights and getting a great start on fuel level. Not this trial and error nonsense that seems to be what is being preached in this thread. I saw it mentioned here already and from my own experiences I can vouch that I've rarely had to remove carbs to adjust floats after using the proper float height measurements. If I did is was a very minor adjustment on only one or two floats or a rare case of one of the other problems I mentioned earlier.

That DIY a couple post up is a good one. Briefly it states, set fuel level in one carb, remove bowl, take float measurement, transfer that measurement to the rest of the floats. Brilliant, but it is still doing the same thing that snowwy got crucified for here and that is using a float height.

It doesnt say. Put carbs together, install carbs on bike making sure they are in a special orientation, attach tubes to each carb, take fuel measurement, write down results, remove carbs and drain bowls, based on fuel measurements figure out what direction you need to bend needle valve tab, bend it alittle in that direction (hope your not confused at this point), install carbs, check fuel and cross your fingers their all with in spec! This is what that Haynes says to do. Seriously.

The missing information that snowwy was after was simply what is the measurement and what two points are to be measured. I have the measurement (from Haynes) but do not have the two points. I believe I saw 17.5 here earlier and will still try .700" +- .020" Determining if it is the high point of the bowl or the middle is my next goal. Will update this post accordingly.

BTW, the pic above is overkill One tube is all thats needed. I guess there is nothing wrong with being a little OCD. I too am guilty. Personally, I would get some elbow connections in there to get the tube as close as possible to the carb to reduce possibility of parallax error.