Topic: noob carb help...

[domer]

 so im probably going to get a rash of ... for this question but i searched for a good hour and cant find what i need... please feel free to redirect me, yell at, make fun of... what ever floats your boat! oh by the way, im a car guy not a bike guy (yet). so i generally know my stuff, but i got a lot to learn...
     i have a 74 cb 500... i believe, it has a 550 trans, a tank from god knows what maybe a 450, and various other parts i cant identify.... including the carbs. the motor has been previously rebuilt and it runs good (i think, still hasnt been on the road in a while) but the carbs started overflowing on me... classic. so after some research i dropped the float bowls and to my surprise everything looks fairly new, well as in very clean... tiny bit of sediment in the bottom of the bowl but nothin to complain about the floats move freely but one thing i did notice is they are staggered. none are at the same height. and i noticed that all of the float valves are loose ish. meaning if i take the floats off, out falls the float valve (correct term?)otherwise it rests on the float.
that being said.... q #1 should the float valve move that freely?
#2 adjusting the float. im lost here, where should i be bending? obviously the valves arent closing and the floats themselves are all out of wack, where do i start?

the carbs are keihin, but i cant find anything but the manufacturer, and im yet to take them completley off, since shy of this overflow i have no other mechanical issues (that i know of)

i basically know how it all works, but this isnt a holley 750 dp.

here is a carb pic if it helps.... sorry for the crappy pic... thanks in advance!

[750goes]

there has to be a number stamped on the carbs somewhere, then do a search for the settings - it should also be on here somewhere.

take the carbs off as you have pods - it should be relatively easy..
floats should be the same height - if not you are going to have issues, would also give them a good clean - then you know it is done..

[jeepster]

+1 on taking the carbs off. Pretty much impossible to set the float height with them on the bike.

[flybox1]

i will chime in as i sufffered from NCS (newbie carb syndrome) once.  
welcome to the forum!
1.  yes.  freely up and down is good, but fully closed is most important.
if your float heights are set correctly, and the springs inside the float needles good, your fuel will shut off when its supposed to(barring sediment getting int he way.  while your tank is off, check it, and your fuel lines, or even clean them from debris)
2. check the float to be sure it is level, first.  the metal tang which depresses the float needle is what you 'bend" do adjust your float heights.
when installed you will measure the float height when the 'tang' is resting against, but not compressing the float needle.
all should be the same height, and shut fuel off at the same time.
good luck..and keep asking questions.
a plethora of knowledge and help, sweet bikes, cool people, hot chicks, and tons of opinions....there's no place like the forum.
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[Johnie]

Hey...we like newbies here!!!  Soon you will be helping others too.  For more carb info go to the FAQ area and click on carb section.  Lots of fun stuff there.  As far as the float valves it is a good thing when they move freely.  And if the float height is wak that could be the cause.  Set the floats to your specs and move on from there.  Best to do with the carbs off.  My manual says to set the carbs slightly on the side until the float contact point just touches the needle.  Set the float height from that spot.  Let us know how you come out.

[TwoTired]

     i have a 74 cb 500... i believe, it has a 550 trans,

Well that's confusing as the last US model Cb500 was in 73.  74 was the first year for the cb550 with the improved trans.  Did someone put 498cc cyliders on teh 74 lower end?  There should be an engine serial number.  We can tell what that is from that.  On the front of the cylinders is cast the displacement. 544cc is 550 and 498cc is the 500 model.

... the carbs started overflowing on me... classic. so after some research i dropped the float bowls and to my surprise everything looks fairly new, well as in very clean... tiny bit of sediment in the bottom of the bowl but nothin to complain about the floats move freely but one thing i did notice is they are staggered. none are at the same height. and i noticed that all of the float valves are loose ish. meaning if i take the floats off, out falls the float valve (correct term?)otherwise it rests on the float.

First, understand that the slow jet fuel metering orifice is about 0.016 in in diameter.  "Sediment" particles larger than that won't go through and will block their function.

The float valve must move freely to function properly.  The float is what holds it in place normally.  Be aware there is a down stop tang adjustment for the floats, so they should all hang just low enough so they can't reach the bottom of the float bowl when installed.  The little tang on which the float valve spring pin rests is what you bend so that when the lowest part of the float is 22mm away from the bowl base on the carb the valve should "just" seat in the valve housing.

You can check the slow jets for blockage with the carbs on the bike.  With talent, you can also set the float height.  Particularly, if you enjoy contorted positions. 

that being said.... q #1 should the float valve move that freely?

Yes

#2 adjusting the float. im lost here, where should i be bending? obviously the valves arent closing and the floats themselves are all out of wack, where do i start?

Don't confuse the hanging free float position with the valve closure position.  Find the hang stop tang, and the tang on which the float pin rests.

the carbs are keihin, but i cant find anything but the manufacturer, and im yet to take them completely off, since shy of this overflow i have no other mechanical issues (that i know of)

The carbs are stamped with a set up on each individual carb mount flange, top right.

While you have the float bowls off, check the stand pipe in each one for cracks.  These can leak regardless of float position adjustments.

Cheers,

[domer]

you guys rock! i was expecting to wait a week for a answer. thanks a bunch and ill let ya know how it goes....
twotired.... ill double check the numbers but i was pretty sure it was a 74.... i know its a 500 frame, and a 550 trans (by the clutch cable entry point) but this thing is so many different bikes put together by god knows how many people.... me being an avid enthusiast of the funny green stuff    i could be wrong the whole way around, but when i get off work here ill defiantly update my #s...  thanks a million folks, you just saved me a crap load of guess and check!!!

[TwoTired]

As far as I can tell, the 500 frames and the 74 550 frame is identical.  Frame change in 75 model year and again for the 77 model year (K models anyway).


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[domer]

well i wasd wrong.... mostly. the dmv paperwork says 74, but frame is 72... numbers are good, so somebody botched some paperwork somewhere...