CB77: Repair Log - 1998: Jan

Date

[ 1998: January - June ]

06.20.98

Mileage: 11,487

Cleaned and regapped the spark plugs. Went riding. Battery died. Pushed the bike into a service station and put the battery on a charger for 1/2 hour. Rode home. Made a resolution to solve the charging situation once and for all.

Stator

Checked the stator winding output leads for continuity - all OK.
Checked for short to ground - no short to ground; the stator appears to be fine.

Selenium Rectifier [SR]

The bike has an aftermarket rectifier; only four plates instead of the OE eight. The leads correspond to the OE setup - Yellow, Red and Brown terminals.

The following current flow tests were made in two series; the first using the 1964 SR and the second using the 1963 OE SR from the parts donor CB77:

1964 Selenium Rectifier:

Leads	Y + R	R + B	Y + B
+ -	15.4 Ohms	86.7 Ohms	101.1 Ohms
- +	15.5 Ohms	85.1 Ohms	100.1 Ohms

To Ground	Yellow	Red	Brown
Ground = +	7.62 kOhms	7.64 kOhms	7.73 kOhms
Ground = -	13.21 kOhms	13.21 kOhms	13.27 kOhms

1963 Selenium Rectifier - OE

Leads	Y + R	R + B	Y + B
+ -	9.43 kOhms	15.21 kOhms	17.29 kOhms
- +	20.62 kOhms	8.36 kOhms	23.87 kOhms

To Ground	Yellow	Red	Brown
Ground = +	5.25 kOhms	11.82 kOhms	10.83 kOhms
Ground = -	15.90 kOhms	27.03 kOhms	27.64 kOhms

Two things stand out immediately:

a) The aftermarket SR gives a reading in Ohms (between leads) vs. kOhms as in the OE rectifier and

b) the direction of current has no significant effect on the resistance regardless of polarity.

From what little I know on this topic, it appears that the 1964 SR is gone. The current is allowed to flow in both directions without any hindrance whereas the 1963 SR appears to be OK, in theory, allowing the current to flow toward the Red terminal (battery) and restricting its flow in the opposite direction.

06.23.98

Mileage: 11,511

Installed the Selenium Rectified from the 1963 parts bike (see 06.20.98, second test).
Tested the stator output (see table below; values in volts)

Wire Color	RPM = 1K [+/- 150]	RPM = 3K [+/- 200]
Brown	6.2 - 6.4	15.4 - 15.7
Pink	5.8 - 6.2	15.4 - 15.7
Yellow	6.1 - 6.4	15.2 - 15.6

Fitted a voltmeter to the battery and went riding. The results are great. The table, below, lists readings taken during riding with the motor in the range of 4K to 6K RPM, under load.

Steering Bars Light Switch Position:	H/L Bucket Switch Position: ON	H/L Bucket Switch Position: OFF
OFF	13.9 - 16.2	12.4 - 12.6
ON - Low Beam	13.8 - 14.5	12.4 - 12.6
ON - High Beam	13.3 - 13.7	12.4 - 12.6

Not bad at all for a 34 year old bike. Almost 400 miles later - no electrical troubles; H/L is ON at all times. Best output is achieved with the H/L bucket switch set to "ON" and the handlebar light switch set to "OFF." This engages the output of all three sections of the stator winding.

The state of the battery has improved (over the course of the next several days worth of heavy night riding) and has gone up from an anemic 11.5 to a more reassuring 12.5 volts at the beginning of a new ride.

Next planned project: solid state "full wave bridge rectifier."

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