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Repair Log - 1964 Honda Superhawk CP77

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[ 1997: October - December ]

10.04.97 First days of working with my new acquisition:

A thorough inspection is first.  Then upon discovery of several electrical connections of questionable durability I take out the soldering gun and some heat-shrink tubing.  Several of the quick- disconnect bullets are unsoldered, the wires trimmed, and then resoldered.  Lots of bolt-on connections are undone, terminals sanded, sprayed with contact cleaner, then reassembled.  Where appropriate, the terminal connections are covered with electrical varnish or with dielectric paste - to seal out moisture.


I quickly discovered that almost every rubber terminal cap (rubber hood) and other wire sealing rubber components has either disintegrated with age or were about to.  The same goes for grommets, but while grommets of most sizes are easy to find, the same cannot be said about the terminal end caps.  Posted this concern to the VJMC mailing list and one of the respondents suggested checking with a lawnmower shop for such items. 

Meanwhile, the battery is receiving a trickle charge...

10.05.97 Continuing work on the electrical connections.  Took the fuel tank off for access to coils and wire looms.  Checked the production label on the harness under the fuel tank and the bike is a 1964, indeed. 

Removed the selenium rectifier for inspection and cleaning.  Found some flaking paint on the lower sides of the cells.  Cleaned and reapplied electrical varnish to seal the unit again.  I noticed that this is an aftermarket unit, same in size found on the 1963 parts Superhawk, but smaller than what originally came in the CP-77.  More research is needed on this, but for now, contact cleaned and sealed, the unit goes back into its bracket.

10.07.97 The carburetors are off for a cleaning.  They are not terribly dirty, (after all the bike was ridden to my house just four months ago) but the right side carburetor float is sunk.  Upon removal from the carb, the float feels heavy and old fuel is noticeably sloshing around inside one of the float chambers.  There is evidence of moderate etching of the brass sides and some pitting, obviously causing some pinholes.  How the bike made it to my house is a mystery, unless the float sunk within the last several months...  In any event, there is more than meets the eye about the carburetors in the CP77. 

First, there are two different era carburetors; the right side is the old, round bowl, type.  This is likely the one with which the bike had left the factory.  The carb shows a moderate to heavy amount of wear and tear, the most significant being (aside from the sunk float) a slide that tends to bind in the top area of its travel - at full throttle.


The left carburetor is the later, square bowl type.  It looks newer and is somewhat lighter  in color.  Internally, there are more significant differences; the slide is made from a different metal than the one in Type I.  It appears to be made from a light alloy or from titanium? as it is noticeably lighter than the older, chrome plated brass slide.  There is a difference in the numbering, stamped into the top face of the slide; the left (Type II) has "125" and "2.0",  while the right (Type I) has "PW26R" and "2.0".  Another important difference is in the design of the inlet needle; on the Type I the needle tail (which comes into contact with the float tab) is spring loaded within the needle itself, while on the Type II carb the needle is a monolith.  This comes into importance at the time of setting the float (see the entry for 10.08.97).  I also noticed that the length of the slide return spring is longer than the one in the Type I carb.  In addition, the design of the float buoys are different - round sided in Type I, flat in Type II.

10.08.97 After spraying down the carburetors with spray-can carb cleaner, I drove over to a nearby gas station and asked whether I could make use of the air hose.  They said "yes" and gave me the blower attachment.  After blowing the carbs out, I went home and realized that  I was not sure about how to set the float level; I knew the principle and had done it many times before on other carburetors, but I didn't know the points at which the measurements are to be taken on the CB-77 Kei Hins. 

Another question posted to the VJMC mailing list and everything is clarified.  A diagram is worth a thousand words...

10.16.97 Having decided to limit the riding, due to the newly formed (newly discovered?) flat spot on the front rim, I decided that some long-term projects need to be attended to.  First, I'd like to solve the high idle problem which means that the different carburetors need to be replaced with identical units.  I suspect that one of the slides is either sticking or creeps up on its own from engine vibrations.  I had also noticed that the length of the slide return spring had been different among the two carbs; shorter on the older one.  In either event, aside from being different (early, round-bowl and late, square-bowl) the carbs that are in the bike now had only been cleaned with compressed air and not soaked. 

The part donor - 1963 Superhawk - has contributed its matched set of carbs for a full rebuild.  I am hopeful of good results as the 1963 carburetors appear unmolested and the slides were not stuck. 

Upon disassembly, the first carburetor - the right side - appears to have had very little fuel when the bike was parked.  The inside of this carb is very close to pristine.  However a very interesting discovery - the slow jet is damaged.  The throat tube has two fractures in the section below the threads.  This is obviously a defective item since there are no stresses on this part whatsoever.  I wonder if the same condition might exist in one of the carbs on my bikes and whether such damage might contribute to a high idle.


The second carb - the left side - had more fuel in it.  Lots of yellowish powdery residue on the bottom of the lower bowl; some on the upper carb body as well.  Some corrosion is preset on the brass parts, especially on the jet faces.  To top thing off, the float is sunk (fuel still sloshing around inside), making for a 50% float failure rate, based upon the sample of four carbs. 

Disassembly completed, the carbs go into the carburetor cleaner for a thorough soaking.


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