Topic: 1978 CB750 totally dead..

[crousos]

No lights... No action and No cameras..

After spending about an hour today with my two best friends (shop manual and multimeter) I traced the issue down to the actual ignition switch. As I started looking in to finding a replacement the question I have is ...what happens to the seat lock? is there a way to match the keys? or replace the ignition but keep my old key?


Constantin

[OldSchool_IsCool]

Check the connections, they may just need cleaning.  I'm not sure if you can clean the contacts inside the switch.

Yes, keep the old key for the seat and the new for the replacement ignition if you go that route.

[cookindaddy]

A good locksmith can make a new seat key to match you new ignition lock or vice versa.

But +1 on checking the connection at the switch. You don't give much detail but it is (on a 30+ year old bike) very likely that the connector that attaches at the bottom of the switch may have corroded contacts making it seem that the switch is bad.

[crousos]

thanks rotortiller, I though it was all one piece, I will try that before I order a replacment.

cookingdaddy, once I remove the connection from the switch and put a wire between the black and red wire everything comes to life. Both the connectors on the switch side and the plug look clean.

[cookindaddy]

crousos - it does sound like you have a bad switch

Good luck with getting it going

[BobbyR]

The switch disconnects from the lock cylinder via two tabs at the bottom of the cylinder. It is a very simple switch and may be repaired or replaced. When I bought my bike i had to wait for a key, so I undid the switch and used that when i worked on the bike. Very simple job to do. PM me if you have questions,