Topic: 1971 cb750 starter motor won't ground

[carvedtangent3]

Hi! I'm wrapping up the wiring on a custom cb750 build and my starter motor is not turning over when I press the start button. The m unit start light lights up and the solenoid triggers and voltage is going to the starter, but it will not turn over unless I touch a cable from the starter motor housing to the battery negative terminal. I'm using a brand new ricks starting motor too if that makes a difference. Thank you for any help!

[scottly]

The starter is grounded through the engine case and the frame. Do you have a large cable connecting the battery negative terminal to a good frame ground?

[carvedtangent3]

Thank you, I think that may be my issue. I've been building this bike from the ground up and have been building a custom wiring harness with not much experience. I appreciate the help!

[Don R]

 Some guys ground to the fame with the cable under the engine bolt on the outside of the frame, others prefer to place the ground cable against the engine case between the engine and frame. Actually, either will work.

[beemerbum]

Seems to me that prior to the 1972 K2 750, the big ground cable was between the engine and frame. From '72 on, the cable was outside the frame. Of course, either location is a good ground connection.

[bryanj]

Remember NO PAINT on the bracket where the cable goes and engine touches, also NO PAINT where the small green round terminal bolts on