So i should start by saying this bike 81 cb750c hasnt run (since ive owned it). Wiring was a mess with all the wiring in boxes. I started by seeing if i can get good spark. Connected everything back per the Clymer wiring diagram. First and fourth cylinders have good spark. 2 and 3 nothing except when i turn the key back from the run position to off (seems strange). I swapped the plugs to the spark units and now 2 and 3 are good and 1 and 4 give me no spark except for the key turning from run to off. . I found some spark units on ebay but are upwards of $100 plus. Any direction from the wise brethren??
Spark unit or pulse generator???
- Thread starter Snoosky
- Start date
checking the pulse coil is easy
the 4 wires are in pairs yellow and yellow with white trace
blue and blue with white trace
530 ohms plus or minus 60 ohms between each colored pair
no continuity on any of the wires to ground
check for 12v at both coils
swap coils side to side
swap igniters side to side
the 4 wires are in pairs yellow and yellow with white trace
blue and blue with white trace
530 ohms plus or minus 60 ohms between each colored pair
no continuity on any of the wires to ground
check for 12v at both coils
swap coils side to side
swap igniters side to side
Ok thanks guys. So ive got 12v to each coil on the Bk/w wire.
515 and 519 ohms on the colored pairs.
No continuity to ground.
Swapping the ignitors moves the issue from cy 1/4 to 2/3
Swapping the coils moves the issue from cy 1/4 to 2/3
PO intalled Dynatek DC1-1 coils. Most of what ive read said these are for sohc bikes (points). The coils were new and they do check out ok at around 3.1 ohms each.
My assesment so far keeps pointing me to the spark units unless these arent the right coils.
Are these coils ok for use on an electronic ignition?
Is there a way to check the spark units before i shell out $ for the procom ignitors?
I should mention to that PO had a pair of extra spark units but are the 4 wire (single blue and single yellow) intead of the blue yellow pairs. Any chance of using these??
515 and 519 ohms on the colored pairs.
No continuity to ground.
Swapping the ignitors moves the issue from cy 1/4 to 2/3
Swapping the coils moves the issue from cy 1/4 to 2/3
PO intalled Dynatek DC1-1 coils. Most of what ive read said these are for sohc bikes (points). The coils were new and they do check out ok at around 3.1 ohms each.
My assesment so far keeps pointing me to the spark units unless these arent the right coils.
Are these coils ok for use on an electronic ignition?
Is there a way to check the spark units before i shell out $ for the procom ignitors?
I should mention to that PO had a pair of extra spark units but are the 4 wire (single blue and single yellow) intead of the blue yellow pairs. Any chance of using these??
crazypj
Split personality, I fake being smart
Spark unit is a very common fault with DOHC motors. There isn't a timer anywhere so if ignition is left on without engine running they will burn out
Look for the GM spark unit conversion, mounted on a heat sink with some airflow is should be a permanent cure
Look for the GM spark unit conversion, mounted on a heat sink with some airflow is should be a permanent cure
