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Repair Log - 1964 Honda Superhawk CP77
 


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Date

Progress Report:     July - December, 1998

   
12.01.98 Mileage:  14,949

* Greased all fittings.

* Oil Change to 10W40

Upon cleaning the Oil Filter, I discovered that the O-ring which fits into the oil filter (part #91304-259-010 [48.6 x 16m] - as described on the Honda parts bin label) was broken again. This was a brand new, Honda supplied O-Ring 1,249 miles ago. So was the previous broken one I changed 1000 miles before that. I then thought that the summer heat had made the o-ring brittle enough for it to break up in the 1000 miles of service. But when the second one broke in the same place, in about the same number of cooler weather miles, I had to reexamine the situation closely.

Both o-ring breaks ended up severing the o-ring in two places which gave me two chunks of the o-ring - a 1.5" piece and the remainder. I have to say that the rubber did not appear to be brittle as I thought it was two oil changes ago. The surfaces of the oil filter and the oil filter cap - the two shoulders that comprise the groove in which the o-ring sits when everything is assembled - are completely smooth. Yet the two breaks seem to be somehow related to the position of the oil filter's inner fins.

The only thing I can think of is that the oil filter cap (perhaps even the body) may be slightly out of balance. Could this create the type of a vibration that puts a stress into two spots along the o-ring seat?

The question was posted to the VJMC mailing list and one of the responses recommended using white lithium grease to lubricate the oil filter cap along with the inner walls of the filter body and also to "glue" the o-ring to the cap before reassembly. That way the o-ring has a better chance of not slipping off at reassembly. If it does slip off, it might end up being sliced by the cap as the spring clip is being reinstalled.

* Disassembled the oil filter assembly to reexamine the new o-ring. I should note that the motor had not been started yet by this point.

* The o-ring was positioned correctly.

* Applied high temp. grease to the cap and the filter walls; "glued" the o-ring in place; reassembled.

* Disassembled the oil filter again, before starting the motor, just to be sure everything is fine. The o-ring sat snug in its groove.

I will have to revisit this topic at the next oil change. For now one thing is certain - the o-ring fits its groove perfectly and does not slip off during reassembly. This is certainly true now that I am using grease to hold it in place while slipping the oil filter cap into its place. The only thing that can lead to it breaking up in a short number of miles is excessive vibration of the oil filter housing...

   
09.03.98 Mileage:  13,700

Final Prep for the Long trip:

* Oiled or greased all cables.

* Adjusted the throttle cable to return the proper 1/8" slack at the handle twist.  [Later this proved decisive in almost complete elimination of the high rev sticking condition - a persistent problem on my bike for a long time.]

* Adjusted:

a) the shift pedal linkage & cable
b) front brake shoe linkage & cable
c) rear brake shoe linkage & cable

* Carb bowls off, jet holders off; synchronized the carbs.

* Topped off the battery; distilled water.

* New spark plugs NGK D8HA.

* Reset point dwell and timing.

* Adjusted and lubed the drive chain.

* Oil change to Valvoline 20W50 [this brand of semi-synthetic 20/50 oil is excellent on the highway and in warm weather, but makes for difficult starting in cool weather.  Generic organic 20/50 oils are the next step for the ensuing fall...]

* Gave the bike the final once-over and took off on a 1000-mile trip.

The bike ran excellent; it seems that long and hard highway runs - between 6K and 7K RPM and long sustained (hours on end) speeds of 60 to 80 MPH are to the bike's liking.  Although I make no claim to the universality of this on other SuperHawks, but during these endurance runs, I noticed no degradation in engine performance and perhaps even an improvement as some carbonation was purged from a well tuned motor.  This is without a doubt a testament both to the racing heritage of these motors and to period Honda workmanship.  Think about it, this is a 305 cc motor manufactured 34 year ago!!  Also encouraging is that the new clutch springs seem to have greatly improved hot shifting with hard shifting largely eliminated.

Most of riding was done in two 500-mile days, taking me from Boston, USA to northwest of Montreal, Canada.  At the end of the first day (having already arrived to the final destination) the clutch cable broke; the barrel end which fits into the clutch lever separated from the cable - probably due to the combination of (a) age of the cable and (b) new clutch springs.  The temporary repair was to use cable adjustment hardware to extract all available slack and then to feed the cable end through the clutch lever and then through a tiny nut.   Then the cable/nut end was clamped with small Vise-Grips which were, in turn, secured with a long tie wrap around the handle bars (lest they vibrate open en-route).   After this came together, the clutch cable was readjusted and clutch operation restored.  Say what you will, but this fix worked and I made the return trip of 500+ miles without further clutch incident.

   
09.02.98 Mileage:  13,700

Time for another Road Trip:

Big agenda; I need to address the hard shifting on long rides & when bike is very hot.  New clutch springs have come in and that will give me a chance to examine the clutch disks, plates and other components.

Clutch Report:

Clutch disks: two of the clutch disks are from a CB72 - smaller contact patches - they happen to be the ones behind the wire retainer rings, i.e. deepest in.  They are obviously left overs from the previous clutch work where the PO was too lazy to undo the wire retainers. They are thinner and are breaking down; with visible pitting.  The other four disks appear to be in great shape; they are much newer with lots of meat on them.  I wonder if there is anything wrong with replacing only the two worn out disks..?  I changed the order of reassembly of disks and plates to give the set new mating surfaces; will monitor performance...

Plates:  some plates show evidence of high spots where the grab pockmarks have been obliterated along an edge, but no more than 15% (at most) on a
given plate.  One or two plates show mild blueing from some overheated moments.   The aluminum cap has some mild wear groves along the disk contact path.

Springs:  this is mainly what I set out to do (I decided not to dig deeper to the primary chain, etc., for the time being).  The old springs have thinner coils than the 22401-272-810 replacement springs.  The new
springs are shorter by about 3 or 4mm.  I am concerned with that the new springs are cut rather carelessly - at an angle.  If the old springs are set on end on a bench, they more or less stand straight, but the bases of the new springs are machined such that each has the tower of Pisa lean, to various degrees.

Oil filter:  I was surprised to find that there is a noticeable deposit of aluminized sludge in the filter - after only 1000 miles (600 of those, highway).  I was able to wipe the sludge off with a rag and some
carb cleaner, but I was really really surprised that the oil filter O-ring had brittled up and broke when the oil filter cover came off.  That O-ring had been just fine at the last oil filter cleaning 1K miles ago.  This $3.00 Honda O-ring (the local bearing house did not have the correct size) was installed only about 3,500 mile ago.  Good thing I had a spare.

Gasket:  I was very happy to discover that the gasket I installed 3,500 miles ago was perfect and came off without leaving even a thread of itself on the engine case.   It's all in the prep, I guess...  The last time I installed this gasket, all mating surfaces were cleaned well and the gasket was coated with high temp grease on both sides.  No oil leaks from the case cover either and I was able to reuse this rather pricey gasket.

* Replaced the spark plug wires with a new 8mm wire; cut to length and sealed with silicon paste.

* Installed new spark plug wire caps.

* Cleaned the petcock bowl - lots of debris & sediment!

   
08.11.98 Mileage:  12,700

Continued road trip preparation:

* Side Bags all wired up; they look Great!  Even better when lit up...

* Installed new spark plugs.

* Set the timing.

* Adjusted the valves (excessive lateral play remains on rt. exhaust rocker shaft - noisy when off load at 3-5K RPM).

* Topped off the battery.

* Greased all available components.

* Gave the bike the final once-over.

PS When taken on a long trip, just days after this log entry was made, the bike made an unplanned for 19-hour, 580-mile day run without a single problem!

   
08.10.98 Mileage:  12,700

Continued road trip preparation:

Removed the backup carbs from the cleaner, stripped some parts (jet & holders, one of the floats, needle & seat) and retrieved the desired right side titanium slide.

* Removed the rt. old, chromed carb slide.  Removed the needle and mounted it into the titanium slide.   Reinstalled.

Checked the needle height (with the high speed jet holder removed) and adjusted the needles to protrude by the same length.  The only adjustment that can be used here is the idle speed screw.   Once both needle tips protruded by the same amount, I discovered, to my horror, that the right side slide was significantly higher (in the carb throat) than the left one.   This could mean only one thing - that the needle clip was set incorrectly on one of the slides.

Both were removed and, sure enough, the left slide needle was on the third step, whereas the right one was on the second (as is correct for CB77 bikes).  This is a great discovery as I am positive that no matter how well synchronized the carbs had previously been, they could never have reached the optimum setting, for obvious reasons.  Just to think that I had ridden over 3K miles that way!

* Reinstalled the slides

* Returned the throttle cable adjuster to their default settings and resynchronized the carbs.

A side note here on CB77 carb synchronization.  The only way to really get it right is to have the carb bowls off and the floats and the high speed jet holders out.  Only then can the lower tips of the needles be seen and a truly synchronized action achieved in adjustment.   Additionally, as seen from above, more otherwise invisible carb setting problems may come to light.

* Drained the right side front fork.

* Refilled with 250cc of ATF

Front shock action seems to feel good.  I can't wait to go riding!!!

Began work on wiring up the four tail lights on the side bags.  For now, one lamp (per bag) will turn on with the H/L & T/L and the other will function as a brake light.  Should look excellent from the back.  Later, if I find a way to adapt dual filament bulbs into those small tail lamps, I'll rewire the system to include the Turn Signal function.

* Spliced in (solder connections, of course) a quick disconnect plug leadoff from the T/L wiring harness.

* Began to modify/install proper wiring into the side bags.

   
08.10.98 Mileage:  12,700

Continued with the major tune-up:

* Cleaned and lubed the chain

* Drained the left fork tube; some sludge came out along with evidence of water.  How did that happen?  I wonder...  The bike has not been ridden in the rain and has been mostly garaged and always covered.  Besides, how would water make its way in?  Perhaps this is a remnant of some older condensation - after all, the left fork tube did give cause for concern earlier (see 05.17.98).

*  Ran some ATF fluid through for further flushing and refilled with 250cc of ATF.

* Tightened the shift lever output shaft to linkage collar.

Attention now turned to carbs:

* Removed bowls - some minor particles of rust dust - cause for concern; the tank will have to be treated...

* Checked the floats - not sunk and the needles - light wear, but OK.

* Removed the high-speed jet holders.  Discovered that the right side needle protrudes further than the left by 1.5mm.  Removed slides to make sure the difference is not due to differing idle speed screw setting.

Then I saw that I forgot that earlier, I had changed the sticking left side slide with a newer version - titanium slide out of a newer carb.  The bench comparison confirms - the final needle height differs between the old and new slides.  Time to upgrade the right side to titanium.   [Some backup carbs with titanium slides went into the carb cleaner just now; when done soaking, I'll have the desired right side titanium slide].

Not knowing whether the titanium slide will be available before my trip, I decided to do what I can to alleviate the sticking old style slide in the right carb.

* Removed, inspected cleaned and reinstalled the right side slide.  Lubricated with liquid wrench.

* Installed a heavier return spring (from a backup carb).

The results are very encouraging - both slides snap back when the throttle is released.  Encouraging, but a roadtest will show and both carbs with titanium slides will be better that one.

* Took some slack from the clutch cable and from the ft. brake cable.

Disconnected the 'winker' flasher.  Discovered some corrosion on the contacts.

   
08.09.98 Mileage:  12,700

* Cleaned the points; dressed with emery and flushed with contact cleaner.  Lubricated the point cam wick.

* Set the right side points to .012.  Will need a timing light to finish the other side and the timing.

* Removed and cleaned the spark plugs.  Had to remove some carbon deposits and flush with contact cleaner.

* Readjusted the cam chain tensioner.  The rubber wheel has begun its deterioration, but still spins.   Replacement eminent.

* Removed the centrifugal oil filter.  Found inside some carbon specks - smaller than sand, but large enough to feel between the thumb and finger.  These seemed to be organic in nature - either parts of a deteriorated/ing gasket or one of the chain rollers.  Will monitor...   Also some sludge, but a very small amount.  Someone mentioned that a synthetic oil has very strong detergent qualities; perhaps this is the effect...

* Removed the oil pump; disassembled.  Measured the clearances between the gears and the pump body - OK - and between the gears themselves - seems to be above the upper wear limit.  New gears and gasket placed on order.  The pump strainer screen had one large particle of the stuff that - when broken down further - showed up in the oil filter, but otherwise the oil pump was very clean.

* Changed the oil to Castrol 20W50 and 10W40 (the only oil on hand); will have to get more 20W50 semi-synthetic soon.

The negative battery cable had a lot of corrosion and a crack at the terminal.  I've been meaning to change it for some time; the '63 bike has a good one.

* Finally changed the negative battery cable.  Not easy to break the bottom bolt loose (engine to frame), but it is now done - the last known weak link in the charging system.

* Locktite on the rear fender bolts and some other suspect hardware...

   
08.08.98 Mileage:  12,680

I am preparing the bike for a long trip, away from home.  Not very very long - less than 300 miles, but I'd like to make sure the bike is in top shape for the trip.  Hence the Superhawk is off the road for a major tune-up and adjustment project.

* Changed rear shocks.  The old shocks were losing their dampening action a bit too much and so, since the 1963 part donor bike is also red, the shock swap occurred.  The '63 shocks feel better and the dampening action has returned.  Will have to see whether the '63 shocks will last as the test ride was rather short.

* Finally used the opportunity of the removed rear wheel (hard time removing the spindle - rust & corrosion; white lithium grease on reassembly) to change the rear tire to the Michelin M38S that I acquired earlier.  Both tires are now M38S; new CH inner tubes.

* Changed the rear brake cable to a NOS unit I purchased some time ago.  I was hoping to revive the rear brake operation (it was significantly less than desired), or the practical lack thereof which I attributed to a stretched cable.  The new cable improved the situation only marginally; the culprits are the rear brake shoes - only 1/8" of meat on them.   The new cable is at the very end of its adjustment with still inadequate braking power.  Need new brake shoes...

A short test run reminds me how much out of tune the bike has become; sluggish throttle response, low power, horrible lack of rev-down - sticking carb slide - loose chain and poor front shock damping - the quantity of oil used at the last change (200cc) was, apparently, insufficient.

   
07.19.98 Mileage:  12,430

Oil Change to Valvoline semi-synthetic 20W50.

   
07.19.98 Mileage:  12,360 

Biggest news - Installed side bags!   The CP77 is now a Tourer!!!  Manufactured by Bates, these babies were sold specifically for any of the late sixties & early seventies street Hondas.  In fact, the installation sheet that came with the bags lists CB360, CB450 and the CB750 by name; up to the K2. 

In order to install the bags, I had to remove the original luggage rack w/the rear T/S assemblies, but the side bags have two Tail Lamps each; I'll wire them up on another occasion... 

The bags have their own mounting frame and rails; the front of the rail fits onto the rear shock stud, while the rear rails can be adjusted to mount in various locations.  The best (only?) place to mount the rear bracket on a CB77 is to the tip of the rear fender, utilizing the flipper mounting holes and 6mm machine nuts, bolts and washers. 

* Removed the flipper. 
* Fabricated an inner fender bracket out of 1" wide stock steel. 
* Fabricated aluminum spacers (in order to provide proper alignment) by cutting up small ferrules; hacksaw, then grinder. 

The results are quite good; the bags sit well and while not fully rigid, are not flimsy.  The added functionality is very welcome.  My lifestyle is changing and is steadily progressing toward almost exclusive use of the Superhawk as daily transportation; business and pleasure.  Being able to take along whatever without bungee cords is a great improvement on this arrangement.

  ***

* Tightened/Readjusted the steering head bearing nut.  Took out only about 1/4 of a turn, but there is noticeable improvement in the steering precision.  However, the front shocks are still in need of attention - clunking noise on the rebound.

* One of the rear shock top stud nuts had a stripped thread; replaced with a spare from the '63 parts bike.

* One of the rear fender inner mounting bolts (the bolt directly behind the shock stud) was missing; the other side was loose.  Replaced the missing bolt and tightened the other one - fender feels nice and solid now.

* Readjusted the H/L.  I must say, for a 25 Watt lamp, the illumination is surprisingly good!

* Readjusted the front brake cable; removed some slack - about of an adjuster turn.

   
07.14.98 Mileage:  12,175 

* Changed the Oil; 10W30 

Left mirror mount - stripped thread; mirror & the Turn Signal stalk were flapping around in the wind on a night ride yesterday. 

* Removed the clutch lever, the horn button & H/L switch and the rubber grip (had to use a 2 lb. rubber mallet to get the grip off). 
* Took the mirror mounting base (part of the clutch lever assly.) to the machine shop for a Heli-Coil insert.  $15 later the part is saved. 
* Reassembled all parts and secured the mirror. 

I noticed that the ignition switch spanner ring started to work loose every so often. 

* Locktite on the ignition switch mount ring. 

The bike runs fantastic except for: 

The rear shocks have deteriorated to the point where they provide little if any dampening.

The right exhaust rocker makes excessive noise at most engine speeds, especially when not under load.  Most likely, the bike needs a new rocker arm shaft and a rocker, but if one went, how far behind are the others?  In any event, the motor would have to come out - winter project...

The front end seems less tight than I would like it to be.  Possible candidates for readjustment - the steering head bearings and replacement of the shock oil.

   

 

 

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