Cb350f flooding number 1 cilynder

[stowaway117]

Hey gents. I've been battling this for a few weeks and I'm all out of ideas.
Cilynder 1 floods at startup. Once the bike warms up banging on 3, I pull and dry the plug, reinstall and she purrs on all 4. I just pulled the carbs. Jets, needles, seats and floats are all clean, synced and dialed. Strong spark, timing dialed. I swithched plugs from 1and 4 and had the same problem so plugs are good. Valve lash is perfect. HELP!!

72 CB350F
4 into 1 open exhaust, pod filters, dyna ignition and coils.

 

[stowaway117]

There is also a small amount of fuel coming out of air filter number one when cil. 1 is flooded.

 

[carnivorous chicken]

Four possible things: Your float valve is stuck or faulty, your float is stuck, your float height is off, or you have a leak in your overflow tube (although not likely if you are getting fuel backing up through the filter). You can use a small Philips head on a ratchet or a z-shaped screwdriver to just take off the #1 float bowl (without removing the whole carb rack -- although since you have pods that's also easier...). Recheck the valve. Check that the float moves freely and isn't a: hung up on something or b: simply stubborn to move. IF those check out, remove your rack and recheck your float height. And while your bowl is off, look at the brass overflow tube to make sure there are no cracks.

Are you using an inline fuel filter? Although for some reason a few folks here rant and rave about how much they suck, it's worth putting one in your line -- it's possible that crud is making it's way into your line and preventing the float valve from closing all the way.

One final thing to check: sometime the tang on the float gets caught up on the end of the float valve, preventing it from closing properly. When you check the action of the float and the valve, make sure this isn't a possibility.

Another way to check if it's a stuck float is to turn the gas on and give the float bowl a light rap with a mallet. If it stops the overflow, then there's your problem; and unless you want to rap your float bowl every time you go for a ride, fix the problem...

 

[stowaway117]

roger that, ill bust out the float level guage today.

it gets even more puzzling... this morning i fired her up and cil. 1 is hot and firing, but cil 2 flooded!!! i dont get it. gonna pull the carbs off AGAIN and set all the float heights AGAIN and see what happens. what is recommended for float valve replacement? i put new ones in 2 years ago.
also if it was a float malfunction wouldnt the overflow tubes drain the excess fuel before it overflowed into the intake manifold?

 

[stowaway117]

i have no fuel coming out the overflow tubes.

 

[carnivorous chicken]

roger that, ill bust out the float level guage today.

it gets even more puzzling... this morning i fired her up and cil. 1 is hot and firing, but cil 2 flooded!!! i dont get it. gonna pull the carbs off AGAIN and set all the float heights AGAIN and see what happens. what is recommended for float valve replacement? i put new ones in 2 years ago.
also if it was a float malfunction wouldnt the overflow tubes drain the excess fuel before it overflowed into the intake manifold?

Should -- check your overflow tubes to make sure they're not clogged. Worth cleaning out your passages, especially the float valve. Check to make sure the tang on the float isn't hanging up. If your float valves are 2 years old they're probably fine -- check to make sure the little plunger works easily -- and it's likely gunk that's preventing them from closing properly.

 

[stowaway117]

affirmative on clogged overflow tubes. thanks chicken. i do run an in line fuel filter, im gonna shop around for something with a finer medium. somethings obviously getting past it.

 

[yorkie350]

could well be the finer crud getting hung up in there I had same prob a neat trick is to tape a piece of magnet to outside of fuel line in a natural bend if poss it collects the real fine stuff every so often I pull fuel line remove magnet an away comes the crap works perfect cos ya never get all the crap from an old tank take a look in page one of my first topic cb350f 1st project agh !