Author Topic: Neutral switch is leaking oil  (Read 3700 times)

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Offline philjimpot

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Neutral switch is leaking oil
« on: May 17, 2009, 10:23:12 PM »
Hi Guys,
I did a search on this site but came up empty handed.  I own a 1975 CB750K5 an there is oil leaking from my Neutral switch on the bottom of the case.  The switch works fine and I replaced the O-ring with a new one and it still leaks.  I'm beginning to think that the oil is somehow leaking out of the switch itself.  Not where the switch meets the case.  What are my options?  Do I have to shell out the $56.00 for a new switch?  Or is there a way to seal the switch I have?  Thanks.
« Last Edit: May 17, 2009, 10:24:46 PM by philjimpot »

Offline TwoTired

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Re: Neutral switch is leaking oil
« Reply #1 on: May 17, 2009, 10:35:50 PM »
There is a rubber diaphragm inside the switch, separating the oil from the electrical contacts.  Not usually rebuild-able.

There was a thread some time back about using an automotive switch from a Honda car.  You might try a search for it.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Ace

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Re: Neutral switch is leaking oil
« Reply #2 on: May 18, 2009, 03:43:53 AM »
I had to use some gasket sealer on mine to get it to stop leaking.  The O ring by itself didn't do the trick.  On the bottom of mine where the the screw for the wire goes in, I can't take the screw out cause the entire bottom bit turns around, but not leaking oil and still works.
1971 CB750 K1 - Sold
1978 CB750 F2 Supersport - Sold
1981 CB900 Bol d'or - Sold
2006 CBR1100 XX Super Blackbird - Sold

Offline philjimpot

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Re: Neutral switch is leaking oil
« Reply #3 on: June 01, 2009, 11:59:45 AM »
I tried "Ace's" solution because it was the cheapest.  I looked at the NEW O-ring I installed and it was cut and I'm guessing that is why it was leaking.  I put in a new O-ring and a little but of RTV sealant.  Time will tell if it worked.  Thanks.  

Offline philjimpot

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Re: Neutral switch is leaking oil
« Reply #4 on: July 12, 2009, 01:04:00 PM »
It still leaked after the new o-ring.  OK, I think I figured out what the problem was.  It's not leaking at the o-ring where the switch meets the case.  I ended up replacing the switch with a new one and it fixed the problem.  However, after I removed my old neutral switch, I realized what was going on.  When I tried to unscrew the screw that holds the electrical connector on, the inner portion of the switch was turning as well.  There is some factory sealant on there and I don't think it is sealing anymore.  That's where the oil was coming from.  I didn't take the switch apart to see if it was fixable or not.  If I get around to it, I'll take it apart.  Hope this helps someone else.

Offline Ace

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Re: Neutral switch is leaking oil
« Reply #5 on: July 12, 2009, 02:56:42 PM »
Oh well, at least you fixed it in the end. I'm not sure if you can fix your old one.  I also have a switch or two that the inner bit is moving.  Mine don't leak oil though.....for now  ;D
1971 CB750 K1 - Sold
1978 CB750 F2 Supersport - Sold
1981 CB900 Bol d'or - Sold
2006 CBR1100 XX Super Blackbird - Sold

Offline philjimpot

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Re: Neutral switch is leaking oil
« Reply #6 on: July 12, 2009, 03:23:38 PM »
The switch was leaking from the bottom.  Not where the switch meets the case:



When I broke off the factory sealant with my fingers, it chipped part of the plastic threaded inner part.



I took the Neutral Switch apart and this is the guts:



I feel I probably could have saved the switch by putting new sealant on the threads.  But I already bought a new one so there was no point in trying to save it.  If anything, I hope this post saves YOU $55 dollars if you fix it yourself.