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tbpmusic said:
FLOAT LEVELS - CB/CL450
Another critical issue to run properly is float levels in your carbs.
They’re set at 20mm on a CB/CL450. This procedure can be used for most old Hondas (use measurements to suit your bike).
I always set them off-bike, with real gas running through them (it can get a little messy).
Make yourself a tool from an old credit card, use these dimensions for a 450 :::
Then, hook up a fuel line and use the gauge like this -
s you push up on the float with the gauge, the gas should just shut off when the sides of the gauge contact the carb body (in the notches - you'll see what I mean).
Be sure to hold the carb vertical.


now i am sure i had the tool.....i remember the 20mm spec.
 

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Thanks! I remember seeing that picture of the DIY tool, but I couldn't find it
 

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tbpmusic said:
FLOAT LEVELS - CB/CL450


Another critical issue to run properly is float levels in your carbs.

They’re set at 20mm on a CB/CL450. This procedure can be used for most old Hondas (use measurements to suit your bike).
I always set them off-bike, with real gas running through them (it can get a little messy).



Hey that's pretty cool - I've always just set floats with a pocket rule, off the bike, sliding the clip down to the proper measurment. Never thought to make the tool or do it with the gas on.

Thats worthy of putting in the tech tips area.

Ernie
 

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Discussion Starter · #4 ·
tbpmusic said:
FLOAT LEVELS - CB/CL450


Another critical issue to run properly is float levels in your carbs.

They’re set at 20mm on a CB/CL450. This procedure can be used for most old Hondas (use measurements to suit your bike).
I always set them off-bike, with real gas running through them (it can get a little messy).

Make yourself a tool from an old credit card, use these dimensions for a 450 :::






Then, hook up a fuel line and use the gauge like this -



As you push up on the float with the gauge, the gas should just shut off when the sides of the gauge contact the carb body (in the notches - you'll see what I mean).
Be sure to hold the carb vertical.

my right carb was flooding out like crazy.....today i reset the float and used the method you did with fuel flowing through them......figured i would soak them in cleaner for a number of hours, rinse out, dry with compressed air and reassemble and try it again. that carb was doint that last year and wasnt sure why but looking at how the intake horn was wet with fuel explained why it sounded terrible and kept stalling....no probs out of the left one.
 

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i have a honda cl450k6 from 74 and its now going on at least the 3rd float for the right side carb, i have rebuilt them properly and have replaced everything but the case and still having the problem of floats cracking on you, or at least take on some fuel??? is it something that im doing wrong, i have followed these steps above and have also had a few other people with the 350's look at them and they havent heard of it. any help???
 

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Wish I had ananswer for you, but I don't.
Never had to deal with bad floats - I'm not sure there's anything that would be your fault.
More likely just a string of bad luck on the replacements...........
 

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Bill, Can't thank you enough (and my lucky stars!). Tomorrow is "set the floats on the 450 day!"
Mine starts fine, idles fine and accelerates fine until right around 4500RPM. Once past that, it starts pulling hard right up to redline.
At around 4500, it burbles, stumbles and "dogs".
If I move the choke level slightly on, it improves but doesn't go away.
I will be surprised if setting the floats fixes it. I'm thinking the rust is building up on the petcock screens causing it to run lean. Or, maybe, there is something in the low speed jets.
Looking at other posts, it appears that the right carb seems prone to problems. My right carb is also the one I suspect is a problem. Reaching down and lifting the throttle levers (where the cables attach) individually, the right one does not respond (during this 4500RPM episode) but the left one does.
Will report what I find.
Again-- thanks!!
 

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AHA!!! In the notches!!
I just rushed in to ask "what about the notches?" and re-read the first post. I thought I'd do that before looking stupid.OOOPS! Too late D-OH!

But, while I'm here, thought I would tell everyone the answer to my previously posted problem about the stumble at 4500RPM. I found something really bizarre. The right needle was down in the main jet rather than coming out with the slide. Believe it or not, this is the first time I've done anything to the carbs other than sync em. That the needle was down in the main jet was not as bizarre as the fact that the set screw was screwed all the way in and tight! Something I assume the PO had done? How could this thing run as well as it has for the last 300 miles? I mean, it never ran great but, well enough for me to keep procrastinating and riding it rather than fix it!
Something else I found! The choke plates/butterflies were 180 out! The little flappy thing was on the outside. That explains the badly twisted connector strap. I can't believe how well this thing ran like that. Can't wait to see how it runs now (gonna go Hayabusa hunting!).
Finally (I know I'm hi-jacking this thread-- or darn close). I want to raise the needles to get a little fatter mid range. Any ideas? I was thinking little washers but-- what about tiny "O" rings. I bet the thickness would be more consistent. There IS room between the needle holder and the bottom of the slide tube. .5 or .25 mm would be plenty. It hit me (like that baseball that kept getting bigger and bigger) because I noticed how much slop was in the choke shafts. I was thinking little "O" rings would seal them off (not that it's a big deal, just being anal).
Any experience in raising the needles? Ideas?

UPDATE.


Another D-OH! moment. I can't raise the needles with spacers!!! (unless I drill the slide tube that the needle and holder fit into deeper). All I can do is lower the holder! I feel like a Dumb Bass! Especially after driving to the hardware and sifting through the bolt and nut bins!

Back to square one-- any ideas?
 

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In my experience, the standard 450 carb setup runs a little rich and probably wouldn't benefit from a richer mixture unless you're into all-out acceleration runs - but each machine has it's own characteristics. As far as the choke shafts go, they are before the venturi (in terms of air flow) and a slight air leak probably doesn't make much difference. Leaks between the venturi and the head make a lot of difference.
 

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Thanks for this, Bill! I did mine today and it was easy as could be. I've always hated setting floats but this post made it no problem at all.
 
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