Author Topic: New Visual Float Level Tool for the CB750 (Read 1066 times)

cfairweather · « **on:** January 10, 2025, 10:03:13 AM »

I have been developing a new tool to check the float levels. I will probably sell this tool on eBay soon. A plastic plug with rubber hose clamps will fit snuggly into the large hole on the side of the carb. The clear tubes slide into the clamps and will stay in place unless you pull them out. If you need to adjust the level, turn off the petcock, drain the carb using the tube and remove the carb bowl. Make the adjustment and install the bowl so you can check it again. Makes this task about as easy as it can get. I like to set the levels using the lowest rim edge of the carbs. On the CB750, the lowest edge is closest to the cylinder fins. Simply compare the levels to the lower edge of the rim. The level should not be higher than that edge and can be two or three millimeters below it. You can use a straight edge from the lowest edge or just move a tube over to the lowest edge so you can get a close comparison. I don't recommend starting the engine while using the tool for safety reasons.

willbird · « **Reply #1 on:** January 10, 2025, 11:27:47 AM »

That is a nice setup for sure, nice work.

Bill

BenelliSEI · « **Reply #2 on:** January 10, 2025, 01:15:11 PM »

I’ll be the first to order a set. Slickest I’ve seen so far. PM sent!

MauiK3 · « **Reply #3 on:** January 10, 2025, 01:52:36 PM »

Really nice

Finnigan · « **Reply #4 on:** January 10, 2025, 04:27:06 PM »

Very good idea, thanks for sharing

Tracksnblades1 · « **Reply #5 on:** January 10, 2025, 04:39:17 PM »

Great design..

I like that side by side comparison of the inner and outer..

jwurbel · « **Reply #6 on:** January 10, 2025, 06:33:58 PM »

Looks a lot better than my set up.

Any idea on anticipated cost?

Rayzerman · « **Reply #7 on:** January 10, 2025, 06:35:39 PM »

What is the thread size and pitch? May fit more than 750's I'm guessing......

cfairweather · « **Reply #8 on:** January 10, 2025, 07:55:09 PM »

Thanks for your comments. The drain screw thread size on the CB750, GL1000 and others is M6x0.75. Some Kawasaki bowls also use the same thread size. I am thinking to price it at $30.00 - $40.00 for a set, but I would like some advice.

The brass tube fittings should only be tightened enough to make a seal. The reason: Is it is helpful to be able to screw the fitting into the bowl without the tube turning sometimes. Also, you can adjust the tightness of the plastic mount by turning the nut. If you tighten the nut, it will become tighter in the hole. I like to have it where it is tight enough to stay in, but loose enough to where I can pull it out without loosing the nut.

denward17 · « **Reply #9 on:** January 11, 2025, 04:01:37 AM »

Just as a FYI, these are not needed on the PD carbs (I don't think anyway).

I purchased a set (2) from Z1enterprises a while back to check the level on my 550:

https://www.z1enterprises.com/fuel-level-gauge-tool-kawasaki-suzuki.html

cfairweather · « **Reply #10 on:** January 11, 2025, 04:22:34 AM »

Thanks for the information. I am surprised they are selling each tube for only 9 bucks. I will consider selling my kit for less than I originally thought, maybe $25.00 and $5.00 for shipping ($30.00 including shipping). I will list them specifically for the 1969 - 1976 CB750 SOHC as the mount will only fit these years. The mount fits into the large hole on the carb.

jwurbel · « **Reply #11 on:** January 11, 2025, 06:48:41 AM »

My K2 used 5mm threads, not 6 for what it’s worth

willbird · « **Reply #12 on:** January 11, 2025, 07:26:10 AM »

Quote from: jwurbel on January 11, 2025, 06:48:41 AM

My K2 used 5mm threads, not 6 for what it’s worth

Hmm my for sure unmolested CB750K2 for sure uses M6x.75...I chased a thread to fit on my G4003 Grizzly lathe.

jwurbel · « **Reply #13 on:** January 11, 2025, 07:53:07 AM »

Now I am going to have to look. As I remember the 6 was too big.

willbird · « **Reply #14 on:** January 11, 2025, 08:30:28 AM »

Quote from: jwurbel on January 11, 2025, 07:53:07 AM

Now I am going to have to look. As I remember the 6 was too big.

I bought a set of carbs from Ebay and some had a smaller drain plug so they did make bowls for the round tops that are smaller.

cfairweather · « **Reply #15 on:** January 11, 2025, 05:27:04 PM »

I made 5 kits and put them on EBay for $30.00 and that includes shipping in the USA. If people like them, I will make some more, but for now, just 5 sets.

https://www.ebay.com/itm/276813586992

BenelliSEI · « **Reply #16 on:** January 12, 2025, 07:07:18 AM »

Looking forward to my set. Thanks!

jwurbel · « **Reply #17 on:** January 12, 2025, 07:54:52 AM »

Verified that I have 5mm not 6mm screws. Also matches my Carbtune fitting as well. If you make more, and 5mm is an option, I am in.

Great idea, by the way.

cfairweather · « **Reply #18 on:** January 12, 2025, 09:31:05 AM »

What is the thread pitch of the 5mm drain screw you are using? The vacuum sync hole is a M5 X .8. Sounds like the 5mm drain screw is used on other carb sets, so I will probably look at making some. Thanks for your input. I am pretty sure that someone modified your bowls at some point, because to my knowledge, all 1969-1976 CB750 SOHC bikes, that use these carbs, had 6mm X .75 screws. I am guessing that one of your bowls had stripped threads and someone fixed the threads with an insert. He probably did all four just to make them all the same. This is total speculation and I might be wrong.

seanbarney41 · « **Reply #19 on:** January 12, 2025, 09:43:18 AM »

I have seen the 5mm drain screws on 69-76 type carbs...thinking the 5mm were 69, 70, some of 71?, not sure at all

cfairweather · « **Reply #20 on:** January 12, 2025, 09:47:44 AM »

I have a 1970 and two 1971 CB750s and they have 6mm X 0.75 screws. Interesting...

seanbarney41 · « **Reply #21 on:** January 12, 2025, 09:58:50 AM »

The float bowls are also completely inter-changeable. Also, quite sure I have seen a couple racks with 3 6mm and 1 5mm or vice versa.

cfairweather · « **Reply #22 on:** January 12, 2025, 11:28:34 AM »

I will make some M5X.8 tubes in about a month.

BenelliSEI · « **Reply #23 on:** January 12, 2025, 11:46:50 AM »

I think my Sandcast has the small Derain screws, but easy enough to swap on some later bowls…..

cfairweather · « **Reply #24 on:** January 12, 2025, 12:17:23 PM »

My 70 has smaller screw heads, but it still uses 6X.75 threads.

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Author Topic: New Visual Float Level Tool for the CB750 (Read 1066 times)