CA77 Carb Help please!

[teufelziege]

Hi there....I've posted before about this topic and read as many relevant previous threads before, but I am still having problems with my carburetor. I think...


So, what's been happening is that my bike runs well only with the choke out. It runs best from half to fully out. When it's pushed in, it hesitates, sputters, etc. I was thinking fuel starvation. I've had this carb out about 25 times cleaning it thoroughly. I have the stock jets and brass pieces. I also verified float height, set the mixture to 1.25 turns (and have experimented up to 1.75 turns). No matter what I did/do it runs the same. When the choke is out, it runs like a champ.

Well, frustrated, I went and bought a carb on ebay. The guy cleaned and rebuilt it with the gaskets from a keyster set, but left the stock brass in. I inspected it and readjusted float height, set mixture again and adjusted the idle screw. Put it in the bike and it fired right up. Problem is, IT RUNS EXACTLY LIKE THE LAST CARB. This is a later model carb with the square bowl btw. My other carb is rounded earlier model.

So, I am starting to think this is NOT a carburetor problem? Or that I might be doing something wrong. Any ideas??? Thanks!!

[Dgormley]

Teufel, Have you checked the timing? According to EMO most " Carb problems" are directly related to timing issues. In my experiences with my CL once the timing was spot on it was simple to adjust the carbs for excellent rideability.Follow Ed's recipe to the "T", I had to go over it a few times before I got it right........................Good luck, D

[paperslammer]

So, what's been happening is that my bike runs well only with the choke out. It runs best from half to fully out.

Do you mean it only runs well with the choke open? "Out" is kind of ambiguous...

I agree, check the timing..I've posted a timing walk-through for the CA77 in the Dream thread that might be a little useful.

[jensen]

Was the bike warm when you closed the choke ?
These bikes need the choke much longer than you think / need on modern bikes

[Wilf]

Jensen,

For how long, and why, compared to modern bikes?

Wilf

[teazer]

In my experience (yours may be different) the CB/CL series were really "cold blooded" and needed to be allowed to warm up for quite a while and ran best for the first mile or two with some choke. They are jetted slightly lean at/just off idle and need the extra fuel until they get up to working temp.

More experienced people can jump in, but I also found that aftermarket pipes/missing mufflers and different air filters all made things worse and needed jetting changes to get them right.

You may also like to check the carb flanges to see they are flat and the tufnol spacers/insulators to be sure they are also dead flat on both sides. O rings should be above their mating surface before they are clamped up and not flattened.

[teufelziege]

Thanks guys for the responses. I haven't tackled the timing issue but it definitely crossed my mind. I just wasn't sure since it ran pretty well with the choke "open". Sorry about the "out" terminology. haha...


Anyhow, I'll give that a try.