Topic: need help

[markreid]

i have a 74 cb550 four.  ive been trying to get it running for a while now.  i cleaned the carbs, rebuilt petcock, cleaned tank, installed fuel filter and the thing will run for a short time and then it will lose power.  I try to give it more throttle but nothing happens.  As i slow down I pull in the clutch, downshift and the whole bike goes quiet.  It is totally off. Sometimes it will kick back over and run for however short or long it wants to.  I noticed that i am only getting a trickle of gas if any to the in-line fuel filter and then the carbs.  I can see the gas that is in the fuel line going to the filter going down but no new gas flow into the fuel line. So i took the petcock off.  there was some really fine rust particles in the bowl.  I cleaned the whole petcock out.  Put the petcock back on the bike poured new gas in the tank.  Switched the petcock to the on position and gas came out of both fuel outlets on the petcock.  Hooked both the gas lines up to the petcock and nothing but a trickle comes out and then stops.  If i put the petcock on reserve it doesnt help.  I have no clue.  The bike will start but die as soon as it burns up the gas that trickled into the carbs.  I tried opening the gas cap.  that didnt help.  Does anybody know what could be causing this? i drained the tank and the gas seemed to be clear of debris.  Kinda stumped.

[Retro Rocket]

Gday mate, this is in the wrong section, it should be in the SOHC /4 section. Sounds like you have a blocked breather on your tank. It is inside the fuel cap, clean it out and see what happens.

[Bankerdanny]

There is a tube inside the tank that feeds the petcock with a sleeve over it with mesh sides to act as a filter. Did you remove that before you cleaned the tank?

[markreid]

where is that tube located?  I didnt know there was one in there.  How do you get it out of the tank?  This is my first bike and im trying to learn as much as i can so any advice i can get is appreciated.  Thank You.

[Bankerdanny]

Mine is a '77, so I have a different petcock than you. But in my case it was a snug fit inside the petcock hole at the bottom of the tank. When I pulled the petcock it stayed behind and I didn't even realize it was there.

One of the members with an older version than mine should be able to give specifics.

You should edit the title of your post to say something like: help, fuel not flowing. Clear post heading will help you get more answers.

You also need to say if you have a K or F model as the tanks are different.

[tlbranth]

I had the exact same symptoms. When I chucked the filters the problem went away.

[Retro Rocket]

where is that tube located?  I didnt know there was one in there.  How do you get it out of the tank?  This is my first bike and im trying to learn as much as i can so any advice i can get is appreciated.  Thank You.

Like i said earlier, check your breather, it may well be that the inline filter in the tank is blocked but the exact same symptoms fit the breather being blocked or partially blocked. It creates a vacuum and stops the fuel flowing after a few minutes, then the bike stops, usually in the same amount of time it takes to pull over and try starting the bike again, enough fuel has seeped back to the carbs allowing you to start again and ride off, only to happen again in a few minutes....

[cookindaddy]

You could test that the blocker breather is the problem by leaving the gas cap open a bit, not clicked closed. That way air can go into the tank as gas is used up. If the bike keeps running, look for the vent in the gas cap and make sure that it is clear.