Author Topic: “Clear Tube” Float Level Check Tool?  (Read 1454 times)

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Online BenelliSEI

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“Clear Tube” Float Level Check Tool?
« on: December 19, 2021, 07:00:20 AM »
I have a stand for a cb750 carb rack, that clamps in my vice. I use it to do “bench sync” and final assembly, before installation. I usually set float heights with a plastic, “U” shaped gauge, with good results. On occasion, I stuff clear tubes in the drain holes to check actual fluid height in the float bowl. It’s messy and stinks!

I’m planning on making four fittings that actually screw into the float bowls in place of the drain screws. Thinking of a double barb style nipple (brass), of the correct diameter, that I can turn down one end and thread to match the bowl. Maybe solder on a flat washer to back up an “0” ring for proper sealing? And a small nut on the actual hose barb,  to screw it in with???

Anyone actually made a useful, reusable adapter? Photos?

Offline chiefum

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Re: “Clear Tube” Float Level Check Tool?
« Reply #1 on: December 19, 2021, 07:16:05 AM »
I think someone posted about using these before from ebay. I have something similar that I use, but I didn't make my own.


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« Last Edit: December 19, 2021, 07:52:12 AM by chiefum »

Offline MauiK3

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Re: “Clear Tube” Float Level Check Tool?
« Reply #2 on: December 19, 2021, 07:50:11 AM »
I need to dig mine out for the 750. My Z1 clear tube tool came from Ebay
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Offline kerryb

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Re: “Clear Tube” Float Level Check Tool?
« Reply #3 on: December 19, 2021, 08:07:45 AM »
I make mine from Aluminum
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Online BenelliSEI

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Re: “Clear Tube” Float Level Check Tool?
« Reply #4 on: December 19, 2021, 08:34:17 AM »
I make mine from Aluminum

Kerry...... perfect! Did you start from scratch or modify an existing fitting? John D.

Offline Prospect

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Re: “Clear Tube” Float Level Check Tool?
« Reply #5 on: December 19, 2021, 08:45:18 AM »
I recently did this without using a fitting. I put one end of a tube in a vice and pulled the other with one hand. I used a cigarette lighter to heat the middle part of the clear tube. As you're pulling the heated part will stretch and thus the diameter will narrow. Stop heating and then cut the tube. You will then have a varrying diameter tube which you can jam into the drain holes. It didn't leak. Worked like a charm.

Does anyone use water for testing purposes?
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Offline CycleRanger

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Re: “Clear Tube” Float Level Check Tool?
« Reply #6 on: December 19, 2021, 11:16:33 AM »
I think someone posted about using these before from ebay. I have something similar that I use, but I didn't make my own.


Huh, that's interesting.  I bought some Uberti black powder pistol nipples to use for doing carb syncs.
I think I saw here someone was using them.
Anyway, they work perfect, same thread, just screw in and push on the tubing. 
I hadn't thought about the same solution for the "clear tube" level check tool.

Oh wait, I think I'm confused. I think the pistol nipples I got were for my XS650. Never mind.
Heh, pistol nipples. ::)
« Last Edit: December 19, 2021, 12:12:55 PM by CycleRanger »
Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
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Offline lash

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Re: “Clear Tube” Float Level Check Tool?
« Reply #7 on: December 19, 2021, 12:06:25 PM »
John, I just took some drain screws and drilled them out to solder in some brass tube. Works fine.
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Offline kerryb

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Re: “Clear Tube” Float Level Check Tool?
« Reply #8 on: December 19, 2021, 01:51:59 PM »
I make mine from Aluminum

Kerry...... perfect! Did you start from scratch or modify an existing fitting? John D.

I start with 3/8" dia alu rod from the hardware store.  Center drill with 1/8" and skim the outside surface for trueness (is that a word?)  Then cut the barbed end to fit the vinyl tube, as I recall 1/4" ID × 3/8" OD ($5.00 for 10' @ home depit).  Cut the blank off to leave enough to thread the other end.
Flip the piece in the lathe ( skim cut was for this) turn the threaded end down in two diameters.  All of it to just under 6mm   (.228" i think) and the end to .218" to get the die started straight.  Cut threads m6 x .75 for all of it and trim to correct length.  Cut a little relief for the oring and leave a smooth sealing face on the center section.
NOTE:  I am not a trained machinist, in fact I'm probably doing it wrong...but this method gets me a part that works and I can get it done!  So for the pros... fire away!

John, if you would like me to make a set for you, just send me your address and make a donation in my name to the forum.
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Online BenelliSEI

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Re: “Clear Tube” Float Level Check Tool?
« Reply #9 on: December 19, 2021, 02:00:32 PM »
I make mine from Aluminum

Kerry...... perfect! Did you start from scratch or modify an existing fitting? John D.

I start with 3/8" dia alu rod from the hardware store.  Center drill with 1/8" and skim the outside surface for trueness (is that a word?)  Then cut the barbed end to fit the vinyl tube, as I recall 1/4" ID × 3/8" OD ($5.00 for 10' @ home depit).  Cut the blank off to leave enough to thread the other end.
Flip the piece in the lathe ( skim cut was for this) turn the threaded end down in two diameters.  All of it to just under 6mm   (.228" i think) and the end to .218" to get the die started straight.  Cut threads m6 x .75 for all of it and trim to correct length.  Cut a little relief for the oring and leave a smooth sealing face on the center section.
NOTE:  I am not a trained machinist, in fact I'm probably doing it wrong...but this method gets me a part that works and I can get it done!  So for the pros... fire away!

John, if you would like me to make a set for you, just send me your address and make a donation in my name to the forum.

Kerry.... thanks for the offer. I have a few extra drain plugs. Lash’s solution looks so simple, i’ll Give it a try first. Stay well! John D.

Online BenelliSEI

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Re: “Clear Tube” Float Level Check Tool?
« Reply #10 on: December 19, 2021, 02:01:20 PM »
John, I just took some drain screws and drilled them out to solder in some brass tube. Works fine.

Clever and simple! I’ll make a few. Stay well. John D.

Offline Flyin900

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Re: “Clear Tube” Float Level Check Tool?
« Reply #11 on: December 19, 2021, 02:06:13 PM »
Regarding the testing fluid of choice in the carbs. I used Drugstore isopropyl alcohol, as it doesn't stink like gasoline and will evaporate if small amounts are left in the carb circuits. Quite pure in the 90% range and I have used it for years with no issues on bikes that run right away or sit for years.
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Offline Alan F.

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Re: “Clear Tube” Float Level Check Tool?
« Reply #12 on: December 19, 2021, 02:10:33 PM »
That is a handy tip. So the specific gravity of ~90% isopropyl is similar to the fuel we can buy these days then. This may not always have been the case but it sure makes setting float heights on the bench much cleaner.

Offline kerryb

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Re: “Clear Tube” Float Level Check Tool?
« Reply #13 on: December 19, 2021, 02:39:42 PM »
Regarding the testing fluid of choice in the carbs. I used Drugstore isopropyl alcohol, as it doesn't stink like gasoline and will evaporate if small amounts are left in the carb circuits. Quite pure in the 90% range and I have used it for years with no issues on bikes that run right away or sit for years.

Great tip, I shall use that.  It will keep me out of the doghouse a little more because I won't come back in the house to "you smell like gasoline!"   
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Online BenelliSEI

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Re: “Clear Tube” Float Level Check Tool?
« Reply #14 on: December 20, 2021, 07:29:16 AM »
Regarding the testing fluid of choice in the carbs. I used Drugstore isopropyl alcohol, as it doesn't stink like gasoline and will evaporate if small amounts are left in the carb circuits. Quite pure in the 90% range and I have used it for years with no issues on bikes that run right away or sit for years.

Excellent TIp..... and we won't Stink up the house! Thanks.