CB77 ignition advance

[davomoto]

I just removed the top end from my newly purchased Cb77. The advance unit appears to have stops welded on it so it won't close all the way. Is this a mod from stock, or is it stock? Also my ignition switch has been replaced with a two wire switch. it actually worked, bike ran and all lights worked. I'd like to replace it with the correct switch, so if any one has one for sale please let me know. Last question, can any one tell me exact year? Frame # is CB77- 105981, engine # CB77E-106030. I just ordered the two book set, so hopefully I will soon be enlightened!

Thanks in advance , Davomoto

[jesmed]

My camshaft doesn't have those stops. As far as I know, that's someone's attempt to limit the amount of advance mechanism travel. If the books you ordered are the ones by Bill Silver, you'll find he emphasizes the importance of checking ignition timing with the throttle open and making sure that the spark advance does not exceed the allowable limit. Sometimes in order to do that, you have to retard the timing byond what is indicated by the firing marks on the dynamo rotor. A previous owner of your bike apparently came up with another way to limit the amount of advance. Maybe he was racing it or had some other performance reason I'm not aware of.

[davomoto]

Thanks for the info! I just won a NOS advance on ebay, and will replce the one in the bike with it. Yes the mauals I ordered are the Bill Silver books.