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Discussion Starter #1
What's up guys, so I just bought my first motorcycle. Picked up this CB1000 Custom for $800 on Craigslist. Just a beautiful, well taken care of bike. 21k on the odo
He wanted 1350 but I got him at eight because when he started it up it started puking fuel and had a rough idle, my dad immediately gave me the look but I still wanted It, I wanted it so bad.

Day One,
Bike wouldnt crank, almost lost my mind. Resoldered some contacts inside the starter. Good as new.

Day Two,
Took off the carbs, found the main jet nozzle sitting in the fuel chamber in #4 and loose secondary main jets in carbs #1&4. Tightened those up hoping it would kill the overflow problem. Nope. Settled the idling problem right away but still puking fuel..

Day Three,
Removed the carbs again, found #4 secondary main jet clogged. THIS MUST BE THE SOLUTION! Clean out the blockage, spray with can cleaner, throw the carbs on, still puking gas, but now its backfiring...COME ON!
I now realize that the exhaust pipe on #4 isn't getting hot when the engine warms up, dad says its the spark plug. Got new spark plugs but the carbs are off, so I still haven't tested the new plugs

And another thing I noticed is the left side of the engine is noticeably cooler than the right side although the pipes still get hot enough to burn me if I touch them long enough.

TL;DR
Carbs are overflowing, and one side of the engine heats up more than the other
 

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Discussion Starter #2
I've inspected the floats and they don't seem to have any holes. I put them in a bowl of water and didn't see any bubbles..

One if them has white discoloration on the orange plastic but other than that I'm at a loss...

I can upload pictures a if that would help.

All the research I've done is telling me that it's a bad float or float valve but I can't see anything wrong!
 

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It is likely a float or float valve issue, and often you won't be able to see anything wrong. A nick as small as a human hair can cause a float valve not to seal, so as a matter of procedure I would replace all float needles and seats. (If you have the replaceable type seats.) I would also check the float height settings.

Also, just on a chance, check to make sure none of the float bowl drains are open, if you have such.

That would be the place to start. Once it's not draining gas you can move on to the other issues.
 

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First, get rid of the old gasoline in the tank. You do not really know how long it has been in there. It is also possible that the tank had some really old gas in it and nearly empty and dirty. Then the seller adds some new gas and that dissolves some crud in the bottom of the tank which then feeds into your carbs. Take that tank off and pour the old gas out into a clean container to observe how much dirt and stuff is in there. If there is anything there, there is probably some in the fuel line feeding the carbs. It might be a good time to add an inline filter from a lawn mower shop, depending on what you find.

Start and run the bike for a bit. Now pull the spark plugs on the non-firing cylinders. They should be wet with gas. If not, your carbs are the problem. on a new to me bike, I always replace the spark plugs with new ones that are correct for the bike and gap to specs. The previous owner could have the incorrect plugs for the bike for all you know...

Taken as a guess, there is a high probability that your needle and seat need replacement.Even if they are not worn, there could be a bit of dirt in the needle/seat interface causing the gas puking. They are wear parts that fail first and they must remain matched up upon disassembly as they wear in together. The previous owner might have cleaned his carbs and put the #4 needle in the #2 carb, for all you know. A new set of needles and seats OEM from Honda [not aftermarket] is a good thing to do. You can also get them from your carb manufacturer and Japanese aftermarket is better than Chinese. Just trying to avoid trouble. In most cases, you can save and clean the rest of the jets in your carb and you will be better off than getting a cheap kit off the internet.

Finally, since you mentioned floats, if yours are solid foam it is unlikely that they will be something you can bubble test. Weigh them on a sensitive scale and compare one to another. Keep us posted on the results.
 

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Discussion Starter #5
OK so I found a dirty float valve seat, put some carb cleaner on a q tip and it shined right up.

I also noticed that the seats weren't pressed in all the way, maybe a mm differencr. So I took the end of a ratchet and tapped them all in.

Threw the carbs on and now its running perfectly!

It stated to dribble fuel from the overflow at first, but now its cherry! I'm so stoked, hopefully this was the problem.

I also got some new DR8ES plugs last night. All four were covered in carbon build up.

Thanks for all the suggestions guys, in the end my lack of experience made me overlook something most people would check right off the bat.

Can't wait to learn how to ride a motorcycle now! Haha
 

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Discussion Starter #6
Mannn... Everything was good...

I made a hole in a plastic bottle put the overflow line in and taped it to the foot peg.

Turns out I didn't crack the cap open so it wasn't vented.
Pull the hose out and it of course..starts puking

I didn't notice any difference in how it was running though..
So I wrapped some wire on the tube, clamped it, and took it for a spin around the block.

God this thing is fun! But still isnt running any differently
 

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Sorry, did not mean to repeat what Eye stated. We were typing at the same time.
 
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