Z900A4 float levels

[sprint]

My A4 also coughs and splutters a bit at tick over and lower revs (plugs seem to indicate a little 'rich' on cylinders 1-3 and 'lean' on number 4) and I'm hoping that new choke plunger seals will improve things but am also looking at the float levels whilst I've got the carbs on the bench (Rob is changing the seals and has said to check that the pilot jet isn't blocked on number 4)
I've sourced a couple of M6 x 0.75 barbed elbow fittings for the drain screw threads and have started on number 4 as that seemed to be the odd one out - according to the manual I've got, the measurement is supposed to be 3mm (+/- 1mm) from the flange face where the float bowl and carb body meet to the top of the fuel level in the tube?

No such thing as a stupid question so here goes......
I understand that it's important to get all the levels 'right' but considering how 'fine' the tolerance is, I'm struggling to get an accurate/consistent measurement - it looks to be around 4mm to me but I seem to get a different measurement every time I look at it! Does this look ok before I carry on with the others or is there an easier way to get the measurement spot on?
Also, is it simply a case of unscrewing the pilot jet on number 4 and (carefully) using one of the tiny, soft bristle 'carb cleaning' brushes to check for blockages?
NB - The bike has electronic ignition and has stood for a number of years with very little use before I got it - although I don't think the carbs have been ultrasonically cleaned in the past, they have been off and have been 'air cleaned' before I got the bike

Cheers in advance

I too have found that the wet level is very frustrating and inconsistent method.

If your carbs are off the bike would it be possible for you to measure the physical float height on one oh the carbs on which you have done the wet level, as indicated in one of my previous post? You do not need the float level gauge just a rule to roughly measure the height to the top of the float from the body face, you do not need to remove the gasket, as that would give some sort correlation between the wet and static float levels.

Can somebody advise what the 22mm level on the data relates to, as I understand it the float height on the Z900A4's with 26mm carbs is 26mm?

[warren3200gt]

Only thing that makes the wet method inconsistent is if you keep changing either the carb set height, remote tank height or keep moving the tube end height between tests. i.e. Your test method is inconsistent.
If you set your remote tank height at the same distance above the carbs as your fuel tank would be on the bike and have the tube set before opening the flow you will get the same reading each time.

[sprint]

My A4 also coughs and splutters a bit at tick over and lower revs (plugs seem to indicate a little 'rich' on cylinders 1-3 and 'lean' on number 4) and I'm hoping that new choke plunger seals will improve things but am also looking at the float levels whilst I've got the carbs on the bench (Rob is changing the seals and has said to check that the pilot jet isn't blocked on number 4)
I've sourced a couple of M6 x 0.75 barbed elbow fittings for the drain screw threads and have started on number 4 as that seemed to be the odd one out - according to the manual I've got, the measurement is supposed to be 3mm (+/- 1mm) from the flange face where the float bowl and carb body meet to the top of the fuel level in the tube?

No such thing as a stupid question so here goes......
I understand that it's important to get all the levels 'right' but considering how 'fine' the tolerance is, I'm struggling to get an accurate/consistent measurement - it looks to be around 4mm to me but I seem to get a different measurement every time I look at it! Does this look ok before I carry on with the others or is there an easier way to get the measurement spot on?
Also, is it simply a case of unscrewing the pilot jet on number 4 and (carefully) using one of the tiny, soft bristle 'carb cleaning' brushes to check for blockages?
NB - The bike has electronic ignition and has stood for a number of years with very little use before I got it - although I don't think the carbs have been ultrasonically cleaned in the past, they have been off and have been 'air cleaned' before I got the bike

Cheers in advance

Can you kindly include a photo of figure 28.

Thanks

[bulldogbobby]

My A4 also coughs and splutters a bit at tick over and lower revs (plugs seem to indicate a little 'rich' on cylinders 1-3 and 'lean' on number 4) and I'm hoping that new choke plunger seals will improve things but am also looking at the float levels whilst I've got the carbs on the bench (Rob is changing the seals and has said to check that the pilot jet isn't blocked on number 4)
I've sourced a couple of M6 x 0.75 barbed elbow fittings for the drain screw threads and have started on number 4 as that seemed to be the odd one out - according to the manual I've got, the measurement is supposed to be 3mm (+/- 1mm) from the flange face where the float bowl and carb body meet to the top of the fuel level in the tube?

No such thing as a stupid question so here goes......
I understand that it's important to get all the levels 'right' but considering how 'fine' the tolerance is, I'm struggling to get an accurate/consistent measurement - it looks to be around 4mm to me but I seem to get a different measurement every time I look at it! Does this look ok before I carry on with the others or is there an easier way to get the measurement spot on?
Also, is it simply a case of unscrewing the pilot jet on number 4 and (carefully) using one of the tiny, soft bristle 'carb cleaning' brushes to check for blockages?
NB - The bike has electronic ignition and has stood for a number of years with very little use before I got it - although I don't think the carbs have been ultrasonically cleaned in the past, they have been off and have been 'air cleaned' before I got the bike

Cheers in advance

Can you kindly include a photo of figure 28.

Thanks

Attached mate

[sprint]

My A4 also coughs and splutters a bit at tick over and lower revs (plugs seem to indicate a little 'rich' on cylinders 1-3 and 'lean' on number 4) and I'm hoping that new choke plunger seals will improve things but am also looking at the float levels whilst I've got the carbs on the bench (Rob is changing the seals and has said to check that the pilot jet isn't blocked on number 4)
I've sourced a couple of M6 x 0.75 barbed elbow fittings for the drain screw threads and have started on number 4 as that seemed to be the odd one out - according to the manual I've got, the measurement is supposed to be 3mm (+/- 1mm) from the flange face where the float bowl and carb body meet to the top of the fuel level in the tube?

No such thing as a stupid question so here goes......
I understand that it's important to get all the levels 'right' but considering how 'fine' the tolerance is, I'm struggling to get an accurate/consistent measurement - it looks to be around 4mm to me but I seem to get a different measurement every time I look at it! Does this look ok before I carry on with the others or is there an easier way to get the measurement spot on?
Also, is it simply a case of unscrewing the pilot jet on number 4 and (carefully) using one of the tiny, soft bristle 'carb cleaning' brushes to check for blockages?
NB - The bike has electronic ignition and has stood for a number of years with very little use before I got it - although I don't think the carbs have been ultrasonically cleaned in the past, they have been off and have been 'air cleaned' before I got the bike

Cheers in advance

Can you kindly include a photo of figure 28.

Thanks

Attached mate

Very confusing with data sheets giving 22mm for the 26mm carbs but also being advised they should be 26mm?

[Al]

The question of 22mm vs. 26mm has come up many times before and i still dont know the answer. With regard to another type of carbs i am aware of at least two different versions of the way it gets measured for that specific variety. One is with the carbs vertically upside down and the other is with the carbs 90 degrees to the horizontal. The latter has the float tang resting lightly against the valve, the former with the valve fully depressed. It would be useful to finally put it to bed but without the test method being stated, the measurement is meaningless. What is consistant though for these carbs as well as most others i have seen, is the 3 or so mm below the float bowl face and the use of the 'wet method' for certainty to quantify this. I prefer this in all cases but do it with the engine running which is fine. It gives a great deal more information than the static 'wet' test with little or no more drama once you get used to it. It also takes out a lot of the inconsistencies of the static 'wet' version!

Anyway; just read the 'early' manual for first generation 900's and in there it says that; "The fuel level is defined as the vertical distance from the centre of the carburettor main bore to the surface of the gasoline in the float bowl". In this case it is given as 32mm +- 1mm but critically,.. it is still 3mm below the face of the top of the float bowl. This is for VM28 which naturally have a different radius component to that calculation than the VM26.
So that is three , at least, different measurements or measuring methods

AL

[sprint]

With the float heights set to 25mm when doing a 'wet' test the the petrol in the bowl is above the body flange, see attached photo, I'm at a loss!

Clearly this is why they were originally set at around 29/30mm which is way above where they should be yet I will still suffering from running rich, though I still have the refurbished choke plunger seals to try, but I don't to fit the carbs again only to have to take them off again so need to get the float levels sorted before I re-fit them.

Any suggestions as how they need tp be set? Ignore the static float height level, that should be more or less right or simply set the wet level around the 3mm below the edge of the body flange what ever the float heights are?

[zed1015]

If the static measurement puts the level too high then you are going to have to do it by the wet method or static at 3 or 4mm lower..
The level needs to be between 2.5mm and 4.5mm below the carb body flange.

[Al]

Just based on the photo above; that would be a great place to start. Choke plungers will make a disproportionately greater difference to mixture strength by far than will a few mm this way or that on the fuel level height. When i do mine i may have to take them on and off four, five times, perhaps more, perhaps less and for this reason, knowing i wont get it right first time i dont fit the airbox. From the photo; the carbs are not level. Thats OK if that how they are when sat on the bike. In which case i would take the reading equidistant between the screws on the side ie. half way along that taper which will change the visual reading by a couple of mm. Similarly; if you move the tube 2mm higher by accident, when doing the readings, that will stay 2mm higher than the true value which is why i do it with the engine running.
The picture appear to show the fuel level in pretty much the correct place if the tube were moved left toward the centre of the float bowl. You are looking for 3mm i believe, below the the joint where the gasket sits, ie; top surface of the bowl which it appears to be, or would be if the hose was in the middle.
After you fit the choke plungers and run it, if you cant adjust the mixture strength weak enough at idle, that would be the time to re-visit the float heights. Sooty plugs will not be a function of a strong idle mixture except if running it exclusively on idle. The idle circuit is a very small fraction of the percentage of fuel in the carbs above idle and whilst it does provide 'trim' for the greater throttle openings, its contribution is minimal unlike 'passing' choke plungers.
AL

[warren3200gt]

Your photo below isn't that clear, it looks to me like the fuel level is way above the top black line?

Any suggestions as how they need tp be set? Ignore the static float height level, that should be more or less right or simply set the wet level around the 3mm below the edge of the body flange what ever the float heights are?

Below the mating faces not the body flange.

Two pages ago

Seems little point in setting them upside down to a measurement to me as each float will behave differently under normal use and will need adjusting using the wet method anyway. The only thing worth doing in my mind at this stage is to ensure the floats are straight and leveled with its partner. Check all the brass hinges are straight and free and that the arms are not bent or twisted at all.
Regarding resetting the tangs I go for the tang to be bent towards the valve by the width of the tang metal. Ie if viewed level there would be no gap between the bottom of the tang thickness and the top of the float arm thickness.
This tends to mean that only a minute adjustment is required when setting them wet.

Only thing to add is are you sure your floats are fitted up the right way? The stop tang is to stop the floats dropping to far NOT lifting too far.

[Al]

Not that line; Meniscus is always defined as the centre of the tube, meaning; read at the centre of the tube so in this case its the lowest part of the downward curve.

AL

[warren3200gt]

Here then.?
Where my less than straight line was meant to be.

[sprint]

Your photo below isn't that clear, it looks to me like the fuel level is way above the top black line?

P1020706.JPG.jpg

Any suggestions as how they need tp be set? Ignore the static float height level, that should be more or less right or simply set the wet level around the 3mm below the edge of the body flange what ever the float heights are?

Below the mating faces not the body flange.

Two pages ago

Seems little point in setting them upside down to a measurement to me as each float will behave differently under normal use and will need adjusting using the wet method anyway. The only thing worth doing in my mind at this stage is to ensure the floats are straight and leveled with its partner. Check all the brass hinges are straight and free and that the arms are not bent or twisted at all.
Regarding resetting the tangs I go for the tang to be bent towards the valve by the width of the tang metal. Ie if viewed level there would be no gap between the bottom of the tang thickness and the top of the float arm thickness.
This tends to mean that only a minute adjustment is required when setting them wet.

Only thing to add is are you sure your floats are fitted up the right way? The stop tang is to stop the floats dropping to far NOT lifting too far.

Unfortunately I do not have a better clear tube but yes that is the level that you have marked, which is around 5/6mm higher that it should be, should be at the lower black marked level.

As an update I changed the float height from 25mm to 30mm and it has made no appreciable difference in the wet level, so I really am at a total loss at to what is going on here as the wet level seems to be totally independent of the float height?

Yes the floats are the right way round, with the tang stopping the floats dropping too far and not lifting too far.

Is there somebody on the forum tat I can send them too as I have run out of ideas, yet it is probably something very basic.

I have a Kester kit, of which I have used some but not all parts trying to keep to original where possible, mainly with the jets etc, but nothing that I can see that should have an impact on the fuel height in the bowl?

[warren3200gt]

If your floats are in upside down the float tang will stop the floats rising sufficiently to fully close the valve. Are you 100% sure the stop tang is pointing down towards the float bowl and not up towards the carb body?

[sprint]

Not that line; Meniscus is always defined as the centre of the tube, meaning; read at the centre of the tube so in this case its the lowest part of the downward curve.
1200px-Reading_the_meniscus.svg.png

AL

Thanks, but the measured height is out by around 5/6mm so the meniscus is not having any realistic effect, I wish it was close enough that it was only a meniscus issue.