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What size/model carbs?

Fuel System: Gas (Petrol) tanks, Carburators
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gbyoung2
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Posts: 60
Joined: Sun May 17, 2015 5:00 pm
Location: N. Chesterfield, VA

What size/model carbs?

Post by gbyoung2 » Thu Jan 30, 2020 3:38 pm

Some of you old timers are probably chuckling at my inane questions, but going to ask anyway; I need to know.

How can I tell what model Keihins my ’67 CL77 has? I have assumed 22’s, but I am beginning to doubt that. Are there any marks on the carb bodies to indicate what they are??

DJM
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Location: Chesterfield UK

Re: What size/model carbs?

Post by DJM » Thu Jan 30, 2020 4:58 pm

The correct carbs are 26mm not 22mm,

I think the model number is PW26 but don't take that as gospel.

There is usually a 26 cast inside a ring on one side of the mounting flange, also the choke arms may be stamped CL77.

These markings aren't universal.

If you can find them CB77 carbs are identical apart from jetting and needles so could easily be modified, some sources maintain that the CL77s run better with CB needles fitted so a set of CB carbs would be a good alternative.

gbyoung2
honda305.com Member
Posts: 60
Joined: Sun May 17, 2015 5:00 pm
Location: N. Chesterfield, VA

Re: What size/model carbs?

Post by gbyoung2 » Thu Jan 30, 2020 5:49 pm

Like so:
Image

And if that's the case and they are 26's, then the correct float heights should be:
Image

I didn't have a manual when I first got the bike, and remembered that a previous one I worked on had the 26.5 mm setting. This is what the ones on this bike were set at, so I assumed they were correct.

Once I got one of the pricey New Zealand manuals, I saw there were a couple of carb variations - but - had no idea what were on my bike. Looks like one of the PO's got it wrong.

Thank you very much. We'll set them to 22.5 mm and see what happens.

Guy

gbyoung2
honda305.com Member
Posts: 60
Joined: Sun May 17, 2015 5:00 pm
Location: N. Chesterfield, VA

Re: What size/model carbs?

Post by gbyoung2 » Sat Feb 08, 2020 1:41 pm

We did set the floats to 22.5 mm above the cut out in the lip. The original float tweaked right in to that setting. The new Honda OEM float a PO provided really needed the tang bent a bunch to achieve the 22.5 setting. The new float was provided since the original had a hole in it.

As mentioned in another section that kind of got sidetracked with tuning stuff, my bike had a bad bogging issue at anything much beyond 1/2 throttle. Another mentioned the air filters being the possible problem, but mine are brand new and recently installed.

A local with another CL ran a slew of jets over for me to try to see if it would help with the issue. My bike has 130 mains in it, and his collection included some 135 and 140's. Fortunately, the jets were early JIS so they fit. I decided to go for the gusto and went with the 140's since the LH carb bowl is kind of pain to get off and back on.

TA-DA!! The 140 jets took care of the bogging... even took it up a fairly decent grade on a street in the neighborhood in 2nd. gear, WOT, and no bogging.

Will leave those in there for now, but may back off to the 135's once I get a few more miles on it. Even tho' it's not idling perfectly right now, don't think I have to fool with the pilot jets - yet. We'll finesse the tuning a little more and we'll see as time goes by.

I’ve resisted putting fuel in the tank since the cleaning and POR15 treatment because I want to give it a fresh coat of paint once the weather gets a little warmer, but may have a change of heart on that. I just may put gas in the tank now so I can ride it around, and deal with the painting thing when the time comes.

Image

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