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Discussion Starter · #1 ·
Good evening, hope everyone is enjoying the riding season.

Sorry if there is an existing thread on this specific subject; but I've been looking for a few days now and haven't seen anything. A lot of good and helpful information; but nothing that shows the information I am looking for, specifically.

I am in the process of cleaning and rebuilding VB22 series carbs on my 78 CB400T II and I am trying to determine "where" on the float I should measure for an accurate float height measurement. I know the measurement is spec at 15.5mm; but I need to know where across the length of the float I should make the measurement.

So the picture below shows the float in the carb. Do I take the measurement on the float closest to the float pin (white line), at the middle section of the float (yellow line), or at the tip or far end from the float pin (blue line)?

Any help with this will greatly appreciated and thank you.

78cb400tII_float.jpg

The Clymer manual for the bike gives an image on how to measure, but they show what looks like the round, plastic type floats. Additionally; they are not clear on where to make the measurement in the text. The Clymer graphic is show here as well.

ClymerImage.jpg


Here's a pic of the bike.

latest beast.jpg
 

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Discussion Starter · #4 ·
Jim/Ninadm:

Good morning.

Thanks for the help and sorry for beating a dead one...

Here is a picture of my current float height measurement on my left carb [CARB]. I am holding the carb with my left hand, and the float height gauge in my right hand. The gauge is set for 15.5mm. I am including a picture of the gauge as well so you can understand what you're looking at. Not sure it is clear enough in CARB photo [GAUGE_FR & GAUGE_SIDE].

I have the float "tab" just touching the metal pin of the float valve and taking my measurement. From what I see, the float height is way, way off and is probably causing me to jack-up the my jet sizes, and causing other problems.

Is this how you read the measurement I am taking? Please let me know so when you can and let me know if you need more information from me.

Again I appreciate all the help and sorry for beating this to death.

CARB

CARB.JPG

GAUGE_FR

GAUGE_FR.JPG

GAUGE_SIDE

GAUGE_SIDE.JPG
 

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Not a problem. Tip the carb the other way so the float needle is seated lightly and the adjustable float tang is just touching. Then measure from the float bowl gasket surface to the highest point of the float.
201_4066.JPG 201_4067-001.JPG
Yeah I know, the second picture has my gauge crooked, lol, but you get the idea
Your gauge looks good to go.
 

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I'm a brand new member with a running 79 cb400t, with about 11k on the odometer, no smoke, good compression etc. It had the 11k on it when I bought it, and I've driven it only about 2-3 hundred. I'm horning in on your thread (which is most recent) to seek some advice on my own carb rebuilds. I bought the gasket kits and including the little vacuum diaphram kits. I've read other threads and watched the "hillbilly" u-tube videos, and including posts by longdistancerider whose advice I'm specifically seeking, please. In retrosprect it looks to me like I've done pretty much what the hillbilly video suggested, but used new parts/gaskets. Now it runs different than before the rebuild, but still blindingly lean, as it runs pretty smoothly (no backfires, good power all the way up to about 60 which is all I've got the appetite for) on about half choke, though the right pipe turned a little blue from my twelve mile test ride. It starts well with only a touch on the button. Without the choke it sounds like my aunt Minnie after eating a plate of beans. The right side seems to be much worse than the left side which was the case before & started me on this carb rebuild odessy. In reading about float level (which I haven't done yet), jet sizes and separately about needle sizes/positions (though they seem to me to go together), I'm wondering now how to approach the problem. It would be easy enough to take out the carbs again & check the float level, but if it turns out that that is ok, what next? Buy some bigger jets?, but if so should I look at some needles too? I'd like to get it right this next time so as not to risk screwing something else up taking the carbs in and out.
Thanks in advance for your help, Mike.........Washington state
 

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Welcome to the forum, Mile from Washington state. Great to see another 400 series here.
A posting in the new members introduction section with a pic of your bike would be nice.
 

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Discussion Starter · #8 ·
Bipper - Do you still have the stock airbox in the bike or did you pull it out and replace it with pods? Is the exhaust stock?
 

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Thanks for the welcome guys. Since my last post of a few days ago, I stumbled into Jim's apparently exhaustive article on rebuilding VB21's. I'm encouraged that few get it right the first time. I'm not sure at this point that there is very much that I can do different than the first time, other than float level, soaking the durn things for half a day, maybe a little polishing, and just being more careful generally, maybe get bigger jets............so I gotta read through it more times and make a couple of changes in my work area before tearing into it/them again . In answer to your kind questions, my airbox is stock (foam & screen), as are the pipes, as is everything else probably as far as I know. I'll also try to get onto the new members page & take a picture, though I'm at least as challenged on the computer as I am on motorcycle mechanics. So you'll know what my interest is, I can say that as a 70 year old, all I want is a reasonably reliable ride strictly for recreation, probably less than 100 miles per trip, probably once a week in summer, though maybe a little more if I can figure out how to get it down to Arizona with me for the winter months.
Thanks again, Mike (a.k.a Ifflebipper)
 
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