79 cb750 carb floats on a 80

CBrat750

New Member
Hey guys I know this sounds like a dumb question but bare with me.

After a bunch of frustration with my carb overfilling, #1 on the rack, on my 80 cb750C I have come to terms that the float is out of adjustment. Well being one of Honda's better ideas the C's have plastic non adjustable floats. But the 79K's have adjustable metal floats and I'm wondering if anyone has switched to use those floats. Both are DOHC motors so I would assume the carbs are the same. But we all know what happeneds when we assume.

Look forward to hearing from the DOHC guys, Ive learned alot from your posts just havn't seen this come up anywhere.
 
make sure that the offending carb has the correct needle valve in it as the needel valves are different depending on the float

so maybe someone mixed it up and that is why it is leaking?
 
Also check to see the float actually floats, has no holes in it or filled up with fuel.

I'm petty certain the carbs are the same VB52, Floats and valves are different part numbers though, so if you replace for an adjustable float I would change all four and the valves as well. Or get another set of carbs, probably cheaper.
 
Valve is all good held the valve in with my finger then turned the gas on and not a drop. So that checked out. Also the float is soild with no leaks. But some one was definitely in there before. The float pin was all chewed up smoothed that all out hoping it was the problem. But to no avail.
 
swap the float to another carb and test if it is the carb/fnv or the float itself

if its the float i have a bunch
 
cxman said:
swap the float to another carb and test if it is the carb/fnv or the float itself

if its the float i have a bunch
I will give that a try on Sunday when I get some time to work on her again.

Reasons why I love this site. Members always lookin out for another!
 
Re: 79 cb750 carb floats on a 80 (update)

Ok so after tweaking with the carbs a bit yesterday turns out they need more work then I thought. The little springloaded pin in the valves are all frozen. One of the floats was out of wack like I thought. And one of the bowl over flow tubes was cracked..found that one out after I cleaned it lol.

Notlob you mentioned it would probably be cheaper and easier to swap the carbs at this point I'm kinda fed up with these ones and I want to run pods. And after reading a bunch everyone says the stock carbs are junk for tuning. What carbs would fit on the DOHC bikes?
 
Keihin FCR's, Keihin CR Specials, Mikuni's, etc. Hell, even a carb'd GSX-R 600 rack fits I believe. There's so many carbs that will fit the 750 it's ridiculous. You could scavenge a set off of a CB900 which might be easier to find and cheaper to buy than a thousand dollar rack of CR Specials. I had a set of VB42's on my 79K model, solid plastic floats are a BITCH to find, ANYWHERE. Took me 3 months to finally find some to replace my bad floats during my build. Keihin doesn't even have them anymore. Even the manufacturer knew they were a shitty design.
 
I found a good deal on a set of gsxr600 carbs but the bowls on them are on a slant. How would they work since my intake runners are flat. Wouldn't it cause the them to flood or do I have to get some custom intake runners also
 
CBrat750 said:
I found a good deal on a set of gsxr600 carbs but the bowls on them are on a slant. How would they work since my intake runners are flat. Wouldn't it cause the them to flood or do I have to get some custom intake runners also

They wont work, you will never get the float height correct. They are designed to fit a canted forward motor with the airbox above. You need Pre 96 ish GSXR750 carbs.
 
notlob said:
They wont work, you will never get the float height correct. They are designed to fit a canted forward motor with the airbox above. You need Pre 96 ish GSXR750 carbs.

Thats what I figured about the carbs. Did a bunch more reading and found that i would need the older style.

cxman said:
http://www.dotheton.com/forum/index.php?topic=53516.msg601325#new

I think i found my christmas present to myself! I love the old school side carbs way better anyway.
 
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