Author Topic: S65-Help with the brass-looking thing that fits the trans drum (pics inside)  (Read 880 times)

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Offline sangyo soichiro

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1965 S65:
The only thing I have left to do in order to put the engine back together is make sure I put this neutral indicator switch thing on correctly.  It fits somehow on the transmission drum, and I'm pretty sure it goes on as I have it in the one photo, but I'm wondering what that hole is for in the transmission drum (am I missing a pin or something?).  I'm also unsure of how exactly this thing works and its purpose.  It looks like it somehow should touch a little brass-looking ball that has the neutral switch wire coming from it located on the mating crankcase cover, but I'm unsure of exactly how it would "know" that it's in the right spot when the bike's in neutral (looks like it could rotate freely on the transmission drum...).

The shop manual doesn't say anything about this piece.

(This was a basket case bike, so I didn't take it apart, and thus never saw how it was on before.)


Can anyone tell me how this piece fits before I close up the engine again?  Does it need to be rotated in a certain way?  Am I missing a pin that should go in that hole in the drum?

Thanks in advance.


1974 CB 750
1972 CB 750 http://forums.sohc4.net/index.php/topic,57974.0.html
1971 CL 350 Scrambler
1966 Black Bomber
Too many others to name…
My cross country trip: http://forums.sohc4.net/index.php/topic,138625.0.html

Offline HondanutRider

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I believe that brass piece is not supposed to be flat as it appears in your picture.  The longer arm on it gets bent at a right angle to fit into the hole you describe.  This then aligns it to a particular spot on the drum, so that when the drum rotates with shifting the other shorter arm will contact the neutral lamp wire end to complete the circuit to ground so as to light the lamp. 

There will be a right and a wrong way to mount this ring depending on which direction the tab is bent.  It would have to be mounted the correct way so that when in neutral the other tab aligns with the switch, which will be affixed to the casing for the transmission internals.

Offline sangyo soichiro

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Thanks HondanutRider!  That makes sense.  The fellow that originally took the engine apart must have bent the tab out for some reason, and that's why it was confusing.  I did at one point try to stick the longer tab into the hole just to see if it fits, and it was close, but seemed a little to wide for the hole, which increased my confusion.  But I bet I can get it in there now that I know it's supposed to go in there.  Thanks again for the info!  I can now finish this bike.   :D
1974 CB 750
1972 CB 750 http://forums.sohc4.net/index.php/topic,57974.0.html
1971 CL 350 Scrambler
1966 Black Bomber
Too many others to name…
My cross country trip: http://forums.sohc4.net/index.php/topic,138625.0.html