cb77 stalling at full throttle

jimpapa · Post by **jimpapa** » Mon Nov 28, 2011 2:35 pm

hi, new owner of a hybrid ca77 dream with a cb77 engine.
bike is setup without any air filter.
runs ok in this setup. from idle to full throttle.
decided it needed air filters but when you put one on it stalls out just past 1/2 throttle.
not sure what to do.
tried adjusting the throttle stop and air screws but it still stalls.
any suggestions?

also noticed when i took the carbs off to check things out that the left side carb was completely dry which worries me. bike had been sitting for a week.
i know the PO had a problem with fuel getting into the crankcase but his posts made it seem he had that figured out.
do you know why the bowl would be empty?
thanks

I'm stripping the bike right down to paint and polish everything so would like to get the mechanical issues figured out first so I'm not dinging up the new paint later on.

davomoto · Post by **davomoto** » Mon Nov 28, 2011 4:31 pm

Probably need to re-jet for filters. Smaller main jet, possibly smaller pilot jet and jet needle adjustment. What # jets are in there now? Empty bowl may have a leak? Remove it and fill it with fuel and observe if the bowl has a leak.

Davo

Jethro · Post by **Jethro** » Mon Nov 28, 2011 4:37 pm

So a CB engine in a CA.
So two carbs.

What type of air filters did you install?

As far as fuel supply, make sure the fuel petcock is put together correctly and that fuel lines are clear. Also, make sure that the float is able to move freely and that the needle valve is opening and closing and supplying fuel. Once you get that carb functioning properly then you can figure out the stalling.

The inop carb would give you problems for sure.

Let us know how it goes.

Also a pic of the bike would be cool. Not many CA's out there with CB engines.

Jethro

jimpapa · Post by **jimpapa** » Tue Nov 29, 2011 12:47 pm

I'll post some more pics when it's all painted up and new tires.
too much of a noobie at this to tell what kind of jets and settings, but according to a post from the PO its #42 and #135 jets and needle is #2423 clip in middle.
going to order Bill Silvers Resto guide, and I'll post back when I'm sure of the info im providing.
and i'll try and see if there's a leak in the bowl.
thanks

Snakeoil · Post by **Snakeoil** » Tue Nov 29, 2011 1:37 pm

Fuel is the crankcase is normally due to a sticking float or a poorly sealing float needle valve. Petcock may be involved as well. All depends if the PO turned it off regularly or not. The purpose of the petcock is to prevent this from happening.

Pull the hoses off that go from the petcock to the carbs and see if any fuel drips with the petcock in the off position. You can get a rebuild kit if it leaks. Easy to do.

Jethro already mentioned the floats and needle valve but thought I'd add some more detail since you are a noob. Float could have a hole in it and this causes it to fill with gas and not float. Fuel continues to pour in from the tank. It ends up gushing out the ports, into the intake and into the combustion chamber where it runs down the cylinder walls, past the rings and into the crankcase. It dilutes your oil and also washes the oil off the cylinder walls. All bad things. Figure out what the actual problem is and FIX THIS FIRST!!

I agree with Davo that it sounds like she's running a bit rich with the air filters added. They act similarly to partially choking the engine.

Bike looks nice, by the way. Welcome to the forum.

regards,
Rob

Hotshoe · Post by **Hotshoe** » Tue Nov 29, 2011 3:31 pm

CA bike with a CB engine with a CL right sidecase.
Congratulations, you've successfully touched all the bases with that bike.