Differences between 1962, 1964, and 1967 carbs?

Spargett · Post by **Spargett** » Mon Oct 27, 2008 7:25 pm

I'd like to know what they changed throughout the design process and what the advantages were between those.

It would be greatly appreciated if anyone who knows can share this information. Someone just informed me that they later switched to the square bowl shape.

e3steve · Post by **e3steve** » Wed Oct 29, 2008 8:07 am

Hope the attached extracts from Bill's manuals help, Scott. No idea why they were changed in design though. Since Soichiro has passed on, I think Bill or Ed are our only hope of finding out!

Rgds,

Steve

e3steve · Post by **e3steve** » Wed Oct 29, 2008 8:10 am

BTW Scott, yours are the late '64 square-bowl type, identical to my '67 pair that I now run. And they have ISOmetric threads, not the earlier JIS*. *Steve's correction from Ed's knowledge base: it appears that this is incorrect -- all carbs have JIS jet threads.

PS: Same as these:

http://cgi.ebay.com/ebaymotors/Honda-30 ... 0303130325

PPS: These are the earlier models:

http://cgi.ebay.co.uk/HONDA-CB77-CL77-C ... otohosting

and the attached pics are from a colleague's genuine '61 CB72, which, of course, are Power Jet types. Click this link for Honda's shop manual overview: http://www.honda305.com/forums/viewtopic.php?t=3461

Spargett · Post by **Spargett** » Thu Oct 30, 2008 1:46 am

You rock Steve.

e3steve · Post by **e3steve** » Thu Oct 30, 2008 6:45 am

Scott, that's as may be! I'm not so sure now; been having a back & forth with Ed (lm) who has more info in his memory banks than Honda themselves these days!

Guys, it appears that some of the info within Bill Silver's publications' pages, which is predominantly my info source, ain't always entirely pukka; Ed kindly PMd me with this info:

All of these carbs used the JIS. Also the NOS carbs being offered that you show came around/about early 1966. The square bowl type before that had the castings for the power jet system which was not used on any CB/CL77 carb issued to the US sometime 1964 thru sometime 1966. I know you read all of Bills info but at times he isn't totally correct. For instance the round bowl carbs changed to square sometime in 1964. First square bowls were changed to last issue sometime in 1966 but there isn't any data as to what actual engine numbers. His statement "current models" doesn't include these carbs but carbs issued for other bike models that came later. The round bowl carbs on your friends bike are the Power Jet issue. There is a way to tell which engine a 26mm carb was issued for by comparing the way (26) is cast on the mounting flange. I'm a grease hand and some printed data doesn't agree with what was actually assembled by HONDA over the years. ....................lm

Ed, thanks for the invaluable knowledge you impart; I hope you don't mind my pasting your scribe here to correct my errors.

Honda's shop manual carb overview here:
http://www.honda305.com/forums/viewtopic.php?t=3461

Spargett · Post by **Spargett** » Thu Oct 30, 2008 2:40 pm

e3steve wrote: The square bowl type before that had the castings for the power jet system which was not used on any CB/CL77 carb issued to the US sometime 1964 thru sometime 1966.

That's very interesting. So why wouldn't the CB/CL77's not use the power jets? Sorry if the answer is obvious, I'm jumping into alot of this information all at once. Still trying to absorb it all ; )

e3steve · Post by **e3steve** » Thu Oct 30, 2008 2:48 pm

Hey Scott, follow the Honda shop manual link in the previous post; there's a Japlish explanation of the Power Jet system.