Topic: Help: Can not get 1978 CB550 to start...

[rocs]

Little background... I just purchased this bike in hopes to getting it running. I bought it from a guy and the bike was last titles in 2009 with the same amount of miles that are currently on the bike. So basically this is telling me it hasn't moved in 5 years. The previous owner did tell me it ran... Weird

So i brought it home and removed the carbs. I disassembled them and remove them off the rack and soaked each individual carb in Pine Sol overnight. Next i rinsed them off and cleaned all the parts before reassembling them.

So I hooked them up to the bike and tried starting it and nothing... I started at the petcock and the fuel flows smoothly from the tank through the petcock . However at this point it does not flow through the carb. There is an air bubble in my clear fuel line. the fuel line flows perfectly when it is not hooked to the carburetors. And when I attach the fuel line to the carbs the fuel will not flow from the tank. It seems as if gravity is not working or something weird.


Anyone have any ideas? I think this is why the bike isn't starting. When I use starting fluid it just about starts running.... Please help. Ive been at this for about 10 hours now..

[Doggie]

Sounds like to me that the fuel is not filling up the carbs. Could be the needle not letting the fuel in or the float hanging up.
                                         Doug

[dave500]

you checked the spark?dont just grind away on the starter if it doesent fire up,find out why,if you had spark id imagine you would get a cough/fart bang out of it?did you fully strip the carbs and remove the emulsion tubes?thats the brass tube full of holes the main jet holds in place.

[rocs]

thanks for the replies guys.

I checked and I am getting spark

I stripped the carbs down. I removed all of the emulsion tubes and cleared every hole on the sides. I feel i did a pretty thorough cleaning of everything.

[harisuluv]

Gravity is always working.  Just soaking the carbs in pine sol overnight isn't going to do it.  Especially on the jets.  If you can't even get gas into the carbs themselves much less the bowls then you have an immediate blockage somewhere.  You're going to need to do some manual verification at certain points.

I would start with the drain plugs, if there isn't fuel in there, it's a very distance between the end of the fuel tube and the bowl area. 

[rocs]

the bowls are filled up. When i opened up the screws on the bowls, gas started pouring out.

i have been doing some research on the forums and there is a possibility the floats are upside down. Does this sound likely due to my complications?
I'm going to check them tomorrow morning.

[harisuluv]

It's possible, keep it in mind, but don't get sidetracked.  You just verified the flow of fuel from fuel ts on the carb into the bowls, so that's great.

Now why isn't it getting from the bowl to the cylinder?  Main suspect: Idle jets.  They are small.  You may think you cleaned them but perhaps didn't get them good enough.

There are kind of a lot of settings, that need to be right when you disassemble them and reassemble.  If you are questioning the floats being upside down you might want to do some research on putting them back together.  You can ask questions here too.

Did you bench sync them?  Mixture screw settings?  Air setup, exhaust setup?

[rocs]

my mixture screw settings were turned 2.5 times.

I do not currently have an air box on. The exhaust is stock with holes from rotting.

Should I try taking my cars off my 1974 cb550 and put them on this new bike?

[rocs]

ok so i took the float bowls off and blew air into the fuel hole and the air flowed nicely

HOwever, when i put the float bowls back on their flow stopped. SO basically my floats are pushing the balancers down and restricting fuel flow.

Any ideas?

[rocs]

also looks like the slow jets were clogged. i never took them out because i didn't know you had to "pull" them out like a tooth. My 74' carbs had screw in slow jets i believe.

[rocs]

Side note: when I remove the float bowls air will flow freely through the fuel vale on the carb. However, when the bowls are on, the float needs blocks the passage for air (fuel ) to go through.