help tuning my CA77 carb AKA Fuel delivery issue?

[teufelziege]

Hello, I've got a 1963 CA77 I've just put together well enough to get it running down the road. Please forgive my "tech talk" as I am not a mechanic and I am trying to describe this as best as I can. Also, I have read many forum posts already and still have some questions.
I fired it up today after dipping the carbs and rebuilding them with "part" of a keyster set. I basically took the advice I found here and only used the gaskets and the idle adjustment screw because it was marred for some reason. The original jets looked very good. There was very little lacquer anywhere in the carb, but I still ran a wire through the jets, blasted the passageways repeatedly and dipped everything in Chemtool carb cleaning solution.

So, I put gas in it and with an empty carb it turned over completely with full choke in about 4 kicks. I was feeling pretty good at this point. I backed the choke to about half and it was still running pretty well, then I had it about 1/4 open where the idle started to dip and run slightly rough. I let it warm up a bit as only a minute had gone by at most. As it warmed up, the engine revs started climbing and I backed the choke to just about off. When it was rather warm, I turned the choke off completely and quickly adjusted the idle screw so it idled at what I thought was around 800-1k rpms. Just a guess...it had a nice steady thump thump thump. It was a running a tad eratic...barely noticable. I had originally set the carb air/fuel mix screw to 1 1/8 turn out. I turned it to about 1 1/4 turn and it seemed to level out a bit.

At this point, I thought it was time to take it for a spin. I jumped on, popped it into gear and it rolled out nicely. I took it easy and got it up to about 30 and gave it a little gas. It didn't give me a rapid response and actually started hesitating under the added throttle...the more I gave, the more it hesitated and made kind of a popping noise. Not backfiring, just a "pup pup pup" type noise. It ran ok if I took it easy, but any time I tried to give it a little extra throttle, it'd hesitate and make that noise.

For some reason, I decided to give it some choke and put it about half choke. The engine revs went up, but when I rode again (even though the idle was way to high) it would actually get up and go under the extra throttle I gave it.

So, what's going on here? I am pretty sure the carb is clean as a whistle. What else can I check or adjust? Does the fuel/air mix screw need to be adjusted? Is it a timing issue? (I haven't even opened that door yet). Im just not very good at all this, but I am learning and very motivated to get this old bike running like a top!

Thanks for any help you guys can give!

Thomas

[nander]

Thomas,
Seems to me that if the bike runs better choked then it is starving for fuel when unchoked. Are your float heights set correctly? Which notch is the clip on the needle set at?

nander

[LOUD MOUSE]

Please clarify.
Ya say CA77 then ya say carbs. .....................lm

Hello, I've got a 1963 CA77 I've just put together well enough to get it running down the road. Please forgive my "tech talk" as I am not a mechanic and I am trying to describe this as best as I can. Also, I have read many forum posts already and still have some questions.
I fired it up today after dipping the carbs and rebuilding them with "part" of a keyster set. I basically took the advice I found here and only used the gaskets and the idle adjustment screw because it was marred for some reason. The original jets looked very good. There was very little lacquer anywhere in the carb, but I still ran a wire through the jets, blasted the passageways repeatedly and dipped everything in Chemtool carb cleaning solution.

So, I put gas in it and with an empty carb it turned over completely with full choke in about 4 kicks. I was feeling pretty good at this point. I backed the choke to about half and it was still running pretty well, then I had it about 1/4 open where the idle started to dip and run slightly rough. I let it warm up a bit as only a minute had gone by at most. As it warmed up, the engine revs started climbing and I backed the choke to just about off. When it was rather warm, I turned the choke off completely and quickly adjusted the idle screw so it idled at what I thought was around 800-1k rpms. Just a guess...it had a nice steady thump thump thump. It was a running a tad eratic...barely noticable. I had originally set the carb air/fuel mix screw to 1 1/8 turn out. I turned it to about 1 1/4 turn and it seemed to level out a bit.

At this point, I thought it was time to take it for a spin. I jumped on, popped it into gear and it rolled out nicely. I took it easy and got it up to about 30 and gave it a little gas. It didn't give me a rapid response and actually started hesitating under the added throttle...the more I gave, the more it hesitated and made kind of a popping noise. Not backfiring, just a "pup pup pup" type noise. It ran ok if I took it easy, but any time I tried to give it a little extra throttle, it'd hesitate and make that noise.

For some reason, I decided to give it some choke and put it about half choke. The engine revs went up, but when I rode again (even though the idle was way to high) it would actually get up and go under the extra throttle I gave it.

So, what's going on here? I am pretty sure the carb is clean as a whistle. What else can I check or adjust? Does the fuel/air mix screw need to be adjusted? Is it a timing issue? (I haven't even opened that door yet). Im just not very good at all this, but I am learning and very motivated to get this old bike running like a top!

Thanks for any help you guys can give!

Thomas

[teufelziege]

Uhm, not sure what needs clarification. I have a 1963 Honda Dream CA77 and I believe I am having carburetor problems. It could be something else non-carburetor related i.e. timing, ignition, etc. This bike was non-running, abandoned for many years and so I took the carb off to "refurbish" it.

Please clarify.
Ya say CA77 then ya say carbs. .....................lm

Hello, I've got a 1963 CA77 I've just put together well enough to get it running down the road. Please forgive my "tech talk" as I am not a mechanic and I am trying to describe this as best as I can. Also, I have read many forum posts already and still have some questions.
I fired it up today after dipping the carbs and rebuilding them with "part" of a keyster set. I basically took the advice I found here and only used the gaskets and the idle adjustment screw because it was marred for some reason. The original jets looked very good. There was very little lacquer anywhere in the carb, but I still ran a wire through the jets, blasted the passageways repeatedly and dipped everything in Chemtool carb cleaning solution.

So, I put gas in it and with an empty carb it turned over completely with full choke in about 4 kicks. I was feeling pretty good at this point. I backed the choke to about half and it was still running pretty well, then I had it about 1/4 open where the idle started to dip and run slightly rough. I let it warm up a bit as only a minute had gone by at most. As it warmed up, the engine revs started climbing and I backed the choke to just about off. When it was rather warm, I turned the choke off completely and quickly adjusted the idle screw so it idled at what I thought was around 800-1k rpms. Just a guess...it had a nice steady thump thump thump. It was a running a tad eratic...barely noticable. I had originally set the carb air/fuel mix screw to 1 1/8 turn out. I turned it to about 1 1/4 turn and it seemed to level out a bit.

At this point, I thought it was time to take it for a spin. I jumped on, popped it into gear and it rolled out nicely. I took it easy and got it up to about 30 and gave it a little gas. It didn't give me a rapid response and actually started hesitating under the added throttle...the more I gave, the more it hesitated and made kind of a popping noise. Not backfiring, just a "pup pup pup" type noise. It ran ok if I took it easy, but any time I tried to give it a little extra throttle, it'd hesitate and make that noise.

For some reason, I decided to give it some choke and put it about half choke. The engine revs went up, but when I rode again (even though the idle was way to high) it would actually get up and go under the extra throttle I gave it.

So, what's going on here? I am pretty sure the carb is clean as a whistle. What else can I check or adjust? Does the fuel/air mix screw need to be adjusted? Is it a timing issue? (I haven't even opened that door yet). Im just not very good at all this, but I am learning and very motivated to get this old bike running like a top!

Thanks for any help you guys can give!

Thomas

[teufelziege]

The needle is set to the exact middle position which it was when I took the carburetor apart. Uhm, I didn't check float height. Best way to do it without a specialty tool? What are my tolerances?
Thanks!
Thomas

Thomas,
Seems to me that if the bike runs better choked then it is starving for fuel when unchoked. Are your float heights set correctly? Which notch is the clip on the needle set at?

nander

[Hahnda]

I think EMO's comment comes from the fact that the CA77 has a single carb but you refer to carbs in the plural form.

Anyway the float height can be measured with a ruler.

Refer to this post.
http://www.honda305.com/forums/viewtopi ... d698cc8116

I would also double check your jets. Sometimes on an initial startup you can get a bit of crud in them from who knows where. All I know is that it has happened to me.

[teufelziege]

Ah yes, I see now. There is just one carburetor that I am working on.

I will take off the carburetor, recheck my jets and measure my float height. Thanks for the advice!
OH, btw, was I correct in leaving the Keyster jets out? My understanding from what I've read is they didn't work very well in this application. Clarification on that?

Thanks again,
Thomas

I think EMO's comment comes from the fact that the CA77 has a single carb but you refer to carbs in the plural form.

Anyway the float height can be measured with a ruler.

Refer to this post.
http://www.honda305.com/forums/viewtopi ... d698cc8116

I would also double check your jets. Sometimes on an initial startup you can get a bit of crud in them from who knows where. All I know is that it has happened to me.