UPDATE 5/19/25-Experimental alternative to a clear tube when setting fuel level.

Thank you for this post. I learned quite a bit, not the least of which was that Ethanol gas and regular gas will measure out at different float heights, and, hence, the float height must be set with a specific gas type, then, stick with that type.

With multiple carb bikes, especially four, I can see the value of pulling the carb.

For my little KZ200 it is very simple to test the float height without pulling the carb.

I just drain the carb from the little screw on the bottom side, then, using a 3/32" bit of clear, rubber tubing, with one end wrapped with teflon tape, I "screw" the teflon tape into the threaded drain plug hole, then, raise the tube and open the petcock. See below.



Then, to measure:

msanch08 wrote: Thank you for this post. I learned quite a bit, not the least of which was that Ethanol gas and regular gas will measure out at different float heights, and, hence, the float height must be set with a specific gas type, then, stick with that type.

With multiple carb bikes, especially four, I can see the value of pulling the carb.

For my little KZ200 it is very simple to test the float height without pulling the carb.

I just drain the carb from the little screw on the bottom side, then, using a 3/32" bit of clear, rubber tubing, with one end wrapped with teflon tape, I "screw" the teflon tape into the threaded drain plug hole, then, raise the tube and open the petcock. See below.

Then, to measure:

That's exactly how we do the late '74 and '75 Z1 carbs that have the small drain screws, but we do them off the bike, unracked.

Good Ridin'
slmjim & Z1BEBE

Hi do you have any idea what the fuel level (in mm from the carb body using the wet/clear tube method) should be on the kz200?

TIA
Ben

benjamingray44 wrote: Hi do you have any idea what the fuel level (in mm from the carb body using the wet/clear tube method) should be on the kz200?

TIA
Ben

We don't. We focus on Z1's almost exclusively. If it's not in the factory service manual, don't know where it would be.

Good Ridin'
slmjim & Z1BEBE

I had to do a head gasket change on one of my Z1B's.  During reassembly I decided to check my carb floats while the carbs were off the bike.  I used the Slmjim method, which I have found to be much faster and cleaner than using a cleartube.  I think Slmjim's method is a significant innovation for checking fuel level for carbs off the bike and would recommend we pin this thread to make it easy to find.

Rather than do one carb at a time I decided to do two.  I would have done all four but couldn't persuade my wife to give up more than two glasses to this project, so....two at a time was the best I could do.  For a fuel supply I used my Motion-Pro temporary tank that I hooked to the carbs.

First I pulled the bowls off the outer two carbs, #1 and #4.  You can see the setup below.  My goal was to measure the gap from the top of the fuel to the top of the glass and hopefully get it set at 3.5 mm, plus or minus 1.0 mm.  The second photo shows how I measured the gap....with a micrometer.  I measured to the bottom of the miniscus.  The third photo shows the middle two carbs after they had filled.  All of my carbs measured 4.5 mm, which is a bit low but within range.

 

 

 

This thread was brought to my attention as I am setting the fuel levels on some CVK32 carbs for my kz650.

I see your trying to find alternatives to gasoline when setting the fuel levels.

I remember reading about Alex using Methyl Hydrate to set the fuel levels inside.
It: 
- is less flammable than gas, you really need to put some heat to it to ignite.
- big advantage is smell, and no fumes.
​​​​​​- dries up quickly if spilled.

Varsol and Acetone are more flammable.

wrote:

This thread was brought to my attention as I am setting the fuel levels on some CVK32 carbs for my kz650.

I see your trying to find alternatives to gasoline when setting the fuel levels.

I remember reading about Alex using Methyl Hydrate to set the fuel levels inside.
It: 
- is less flammable than gas, you really need to put some heat to it to ignite.
- big advantage is smell, and no fumes.
​​​​​​- dries up quickly if spilled.

Varsol and Acetone are more flammable.

Unless you use a fluid with the same specific gravity of the fuel you are going to use the whole thing is a waste of time.
Just go by the clear tube method with the + or - parameters stated in the manual for checking on the bike and it'll be just fine.
You won't see any factory or trained mechanic messing about like this and in over 45 years of building and maintaining just about every make and model or motorcycle invented i've never had a problem with the normal procedure.
If the levels are outside the specified specs then remove and mechanically set the float heights as in the manual .
If performed correctly the fuel levels will be within specified operating range.
If the levels are correct and you suffer overflowing or flooding and the floats are not leaking then inspect, clean or renew the float valve.

Using the standard method.  To speed up the process I made a simple carb stand & used a large funnel w tubing as a fuel supply.  Plus I only used 2 screws to secure the bowls (WG says he uses 1 screw per bowl).  I also set up a good/safe/stable spot on the work table for placing the carburetors upside down to remove the bowls.  As for the tang adjustment, I made a simple support for the floats; then, instead of bending the tangs, I flexed each one x-number of times, depending upon the fuel level >> more flexes if a greater adjustment is needed.  I had heard stories of mangled float brackets & damaged tangs.  Doing it this way I was able to set each float to the exact same fuel level.  It's been more than several years & mine haven't changed.  My carburetors don't require the special fuel gauge tool, though, so that helps speed things up.

 

E15 gasoline has an SG of about 0.76, but gasoline in general can vary between about 0.70 and 0.80, depending on grade, additives and time of year.  Methyl hydrate has an SG of about 0.79, so on the higher end of gasoline and about 4% higher than E15 gas.  The higher SG would cause the floats to ride higher and close the float valve a little sooner.  A difference of 4% on 3.5 mm is 0.14 mm.  I doubt that anyone could visually detect that difference, and in any case it is well within the plus or minus 1.0 mm margin of error.  Sounds like it's worth a test.

 

One of the main reasons we were experimenting with alternate wet float measuring fluids was to look for something we could use in a basement shop in the dead of winter, when outdoors work is not practical and powered venting would chill the whole house.  The presence of a standing pilot light on our water heater eliminates very volatile fluids such as gasoline from consideration.

Now that warmer weather has arrived & we can set up outdoors again, we'll experiment with Methyl Hydrate (Methanol) just out of curiosity.  But, it seems that it's quite volatile, with vapor sinking to floor (pilot light) level.  Too, it's toxic to handle.

  Another member suggested Fuel Injection Calibration Fluid.  That's on our list to experiment with this year too.

Appreciate the continuing feedback everyone.

Good Ridin'
slmjim & Z1BEBE

Just about everything available has a higher density than gasoline or will be volatile. 
Even if you mix them with water, some are still going to flammable (e.g., acetone).
 

If the smell is a concern and potential explosion negates any volatiles...Why not use straight water?  You can simply calculate a different setting.  Without doing the math it would be around 4.5 mm plus or minus 1.0 mm.