'68 S32-2 Float Height

[charlie55]

The service manual doesn't give a float height setting for the carbs on this bike. All it says is that the fuel level is 28mm from the center line of the main bore, or 7mm from the brim of the float chamber body. So, I have a couple of questions:

- Since there's no drain on the bowl, I can't hook a clear hose to it and use it as a fuel level sight. Am I therefore correct in assuming that the only way to set the level is trial and error (put bowl on - fill - take bowl off - measure fuel height - adjust - rinse and repeat)?

- The carbs are mounted at an angle on this model, so should the fuel level be checked with the carbs at the actual installation angle, or when level?

Thanks in advance for any insight you can provide.

[Suzsmokeyallan]

Usually set when the carb is level, so hold the bowl onto to the carb body then let it fill from the tank. Then remove the fuel hose carefully from the carb, take the bowl off and measure the height of the fuel in the bowl from the top for a 7mm difference.

[jabcb]

The float floats by displacing gas, just like a boat does.
The float bowl is a small container, so the fuel level with the float in it will be higher than it is after you remove the float bowl.

Two options (others may come up with more):
1) check the float level without a float bowl attached.
Suspend the carb above a small clear container, or rest it on top of the container.

2) use a different float bowl for checking the level.
The float bowl doesn’t need to fit perfectly. No need to use a gasket and don’t tighten the screws.

Per an online parts diagram, the S32 carb uses:
13252-09210 float
13251-09211 float bowl gasket

The 73 TC100 uses the same float & gasket, so its bowl might fit. That bowl has a drain plug & it might fit well enough for the level check.

Looks like there might be a few other bowls that could work too.

[charlie55]

Thank you both for the pointers. Good point about checking for the desired level while the floats are immersed - never would have thought of that. I still don't understand the rationale behind specifying fuel level rather than the much-easier-to-measure float height. I restored a '76 Honda CB125 a few years ago and it was a breeze compared to this baby.

[Suzsmokeyallan]

You have to remember in 1968 the methods of checking or adjusting specified settings on engines or machinery had not really been improved upon since the end of World War 2.
A quick glance at many shop manuals from the 40s to the late 60s show many set guide lines for procedures that were simply done that way because it was tried and proven.
By the time the mid 70s came about many outdated old concepts were dismissed for faster simplfied measurments.