Tool for checking float bowl level.

[KEITH KRAUSE]

I know at least one of you (Jethro?) has made a float bowl gauge. Seems easy enough to me. But first I want to talk about how accurate a home made gauge is, even if used exactly as the factory recommends.
What bothers me is this. I looked up the factory tool and it's discontinued of course. I saw that three parts make up the gauge. Two parts are called fittings and the other a "gauge body". The larger fitting pictured would be the bowl drain screw replacement. The smaller fitting would screw into the large one and the tube/gauge body slips over the small fitting I assume. The smaller fitting is discontinued I'm told by the local Suzuki dealer, so assembling a factory tool is out of the question. OK.
What I don't understand is that the small fitting has an asterisk by it saying "specific to GS1000". How could this fitting be ONLY for the 1000 when several models use the same VM 26 carbs with identical drain screws? These models also have the same float level requirements.
This just gets me to wondering how exact the home made gauge must be to be accurate?
It brings up the questions of:
Does the I.D. of the fitting somehow effect the level you see in your tubing?
Does the tubing have to be the same exact I.D. as the factory tool?
The factory tool also has level marks along the body/tubing that are supposed to be aligned with a specific part of the carb body. Ours would not have that, and so, does it matter how long the piece of tubing you use is and does the bend or dip the tubing takes on effect an accurate read?
You would think that any size/length tubing or any fitting would work, no matter how simple. Wouldn't the level in the hose accurately show/reflect the bowl level?
The factory also says the tool must be located at a very specific location against the carb body. I don't see why it has to be at an exact location, though it's easy enough to follow that.
If location alone can give inaccurate results, it brings up the previous questions and how the reads may be inaccurate if the tool you made differs in any way from the factory tool.
I was thinking of just taking a spare bowl drain screw, drilling it out and installing a 3/16" tube into the hole and sealing it.
I'd like to make the tool but you guys know me, I'm anal about this stuff and wonder about accuracy. Any thoughts/experience appreciated.

[arveejay]

I know at least one of you (Jethro?) has made a float bowl gauge. Seems easy enough to me. But first I want to talk about how accurate a home made gauge is, even if used exactly as the factory recommends.
What bothers me is this. I looked up the factory tool and it's discontinued of course. I saw that three parts make up the gauge. Two parts are called fittings and the other a "gauge body". The larger fitting pictured would be the bowl drain screw replacement. The smaller fitting would screw into the large one and the tube/gauge body slips over the small fitting I assume. The smaller fitting is discontinued I'm told by the local Suzuki dealer, so assembling a factory tool is out of the question. OK.
What I don't understand is that the small fitting has an asterisk by it saying "specific to GS1000". How could this fitting be ONLY for the 1000 when several models use the same VM 26 carbs with identical drain screws? These models also have the same float level requirements.
This just gets me to wondering how exact the home made gauge must be to be accurate?
It brings up the questions of:
Does the I.D. of the fitting somehow effect the level you see in your tubing?
Does the tubing have to be the same exact I.D. as the factory tool?
The factory tool also has level marks along the body/tubing that are supposed to be aligned with a specific part of the carb body. Ours would not have that, and so, does it matter how long the piece of tubing you use is and does the bend or dip the tubing takes on effect an accurate read?
You would think that any size/length tubing or any fitting would work, no matter how simple. Wouldn't the level in the hose accurately show/reflect the bowl level?
The factory also says the tool must be located at a very specific location against the carb body. I don't see why it has to be at an exact location, though it's easy enough to follow that.
If location alone can give inaccurate results, it brings up the previous questions and how the reads may be inaccurate if the tool you made differs in any way from the factory tool.



I was thinking of just taking a spare bowl drain screw, drilling it out and installing a 3/16" tube into the hole and sealing it.
I'd like to make the tool but you guys know me, I'm anal about this stuff and wonder about accuracy. Any thoughts/experience appreciated.

That's exactly what I did. Liquid seeks level no mater what size the hose or how long. You just hold hose along the bowl and let the gas fill the hose up. Works like a charm.

[49er]

The syphon process proves the theory. When you raise the hose above the level of the fuel supply/tank the fuel stops flowing.
You can do a visible check on this theory by attaching a clear plastic hose to a small funnel. Block the end of the hose with your thumb and fill the funnel with water. Hold the end of the hose above the funnel and release your thumb.The water in the tube will immediately find a level adjacent to the level inside the funnel. Raise and lower the hose and it will still maitain that level. Atmospheric pressure is working on both surfaces evenly. When you lower the tube below the funnel level you start a syphon.
The diameter of the hose only limits the flow rate.

[txironhead]

So where on the bowl/carburetor body/etc. is the fuel level supposed to be? I understand the concept of using tubing to find the fuel level, I just don't understand where the "correct" level is. I know how to adjust the floats dry with the carbs off. Is tubing a more accurate way to maintain float level? Seems like it would be more trouble than dry adjustment unless it is much more accurate.

[KEITH KRAUSE]

Yes. Common sense was telling me that it shouldn't matter what size/length the tubing or fitting is. I still can't understand why they say one of the three parts that make up the gauge is specific to my model.
Trying to make something complicated when it's simple. They just wanted you to buy the tool I suppose.
Thanks for the replies.

[49er]

The tubing is used as a temporary visual check on the level of fuel in the float bowl. There was a recent thread on the correct fuel level. From memory, it was 1-2 mm below the bowl ridge where it bolts to the carb body.

[KEITH KRAUSE]

So where on the bowl/carburetor body/etc. is the fuel level supposed to be? I understand the concept of using tubing to find the fuel level, I just don't understand where the "correct" level is. I know how to adjust the floats dry with the carbs off. Is tubing a more accurate way to maintain float level? Seems like it would be more trouble than dry adjustment unless it is much more accurate.

Where to measure? Kind of hard to describe without a pic.
It's approx' where the bowl surface and carb body surface meet. It doesn't have to be perfect. Like the float adjustment method, you can have the level within a range of about 1/10". You're also supposed to place the tube about 20mm from the rear (filter side) of the bowl... at least on several models I've seen.
Someone here have a pic so there's no mistaking the measuring point?
The tube will verify your adjustments. Yes, it can be more work because if you messed up, you'll see it and you get to take things apart again.
Where it really helps is when you re-use float valves that aren't in new/perfect condition but are sealing against fuel overflow. There's bound to be a little sag in the float valve springs. The factory method shows to allow the float to rest on the float valve, then measure. Gravity acting on the valve is allowed, but keep in mind the factory is using brand new parts. But a spring that's anything away from new/perfect, will compromise your intended adjustment. It's difficult to know how much to allow for the sag. It's difficult to know when the float valve positively stops fuel flow. Many owners adjust the floats by standing the carbs up on one end, tilting slightly, then allowing the float to only touch the valve, not rest on it. This is to eliminate spring sag error. But who really knows the exact point when the valve stops flow? Shoudn't it take at least SOME pressure to positively stop flow, not just immediate contact? I've always used the factory method and if the springs are weak, the valve gets replaced. But genuine Suzuki valves are expensive, aftermarket are often cheap/garbage, so I have many times allowed for a little sag. I've never had any float level related problem, rich or lean, by doing it this way.
So in my opinion, if you are careful with your adjustment and use an accurate measuring tool, then levels set with new valves shouldn't need to be verified. Low mileage bikes would tend to have good valves too. There's no significant sag error to deal with. But I would still check if I had the tool. Wouldn't you, out of curiosity if nothing else? Older valves should be verified though. The factory usually allows a range of setting and if you set them in the middle of this range, you'll probably be OK even with moderate spring sag.
You can't argue with what the level says in your tube.

[KEITH KRAUSE]

Also, the factory says to have the bike running at factory idle rpm while doing the check. This would give the most accurate reading.

[49er]

I agree Keith, we can be too pedantic about these settings. If it performs well, leave it alone. I have never bothered to check my float levels with a tube. I just set the floats to the Clymer specs, adjust the fuel and air screws and then road test with plug reads at 3000, 6000 and 9000 rpms. I've never had an issue with float levels.

[Thomas Kenny]

Check out the Haynes manual, it has a drawing showing the correct level of fuel within a range using the fuel pipe attached to the base of the bowl. I have always set my floates to the static numbers with the carbs upside down and it has always seemed to suffice.

[mark]

Pardon my dumb question (its my twisted mind at work) but if the stock float spring has "sag" in it from the weight of the float when the carbs are upside down, wouldn't the pressure of the rising fuel level also raise the float slightly higher with gas in the float bowl? Thus your measurement would be still be reasonably accurate even with "sagging" float springs all adjusted evenly......right?

[Jethro]

I know at least one of you (Jethro?) has made a float bowl gauge.

I was thinking of just taking a spare bowl drain screw, drilling it out and installing a 3/16" tube into the hole and sealing it.
I'd like to make the tool but you guys know me, I'm anal about this stuff and wonder about accuracy. Any thoughts/experience appreciated.

Yes, I have made one. I'll post a pic tonight, but it's really very simple. Basically I did exactly what you are thinking. I drilled a 1/8" hole right through the center of the screw. Then I counter-sunk a 1/4" hole almost all the way through the head of the screw. At the hardware store I found small 1" pieces of 1/4" brass tubes, I think they may have been intended as bushings of some sort. I basically just hammered the tubes into the counter-sunk 1/4" hole on the float drain screw, and to that I can attach a 1/4" I.D. clear fuel line to it. They fit tight and don't leak.

As far as accuracy, I can only guess as to how the tool was intended to function. I always assumed that the intention was to display the actual fuel level inside the bowl, which this tool does perfectly. I actually used a float bowl taken off the carbs, and filled it up with fuel to see if it showed the actual level perfectly, and it does. It seems to be a pretty low tech tool to me, even some of the 2nd party manuals suggest you can simply attach a clear hose to the drain to check the fuel level.

Indeed, what I found was that the springs in the needles do sit differently. I adjusted the float heights perfectly with a set of calipers while the carb rack was on the bench, but using the tubes I found the carbs were off from each other.

[Jethro]

Also, the factory says to have the bike running at factory idle rpm while doing the check. This would give the most accurate reading.

Yes, and it does make a difference there. Start the bike up and the level drops slightly.

I would bet that most people that set thier carbs up using the bench method have slightly lower (leaner) fuel levels than they expect. I know I did. But I guess that depends on the strength of the spring in the needles.

[KEITH KRAUSE]

Yes, that's what I've assumed too. That a lot of people are ending up with lower/leaner fuel levels than they intended. The sag was included in the measurement.

[nert]

I took an extra fuel bowl cut fabricated and sealed a clear mylar window into it.
I scribed (3) lines on it. Lowest allowable fuel level, dead balls accurate, and highest allowable fuel level. I swap the window bowl through all (4) carbs and adjust the floats to obtain as close to desired as i can on each carb. I mount the rack in a vice, use level to adjust left to right. (anal) I have a nice fuel reservoir overhead, and return below. Couple beers later, and 20 times off and on of the fuel bowl, its set.

Curious i am, I measured float height once finished. I found measurements from each extreme (as given in the Suzuki manual) high and low and somewhere in between. But all within the Suzuki range. Worked out this way on three differant racks of carbs. I am sure valve springs as well as float boyoncy, worn pivots, and pins all have an affect on each result.

Its just that KNOWING the fuel level was correct, not just the float level was adjusted correctly made me feel a lot confident.