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Discussion Starter #1
Good afternoon folks! I am new to the twin world and I picked an admittedly leak prone bike (according to most mechanics I've spoken to). I have a 1979 CB400t II and I have it running like a top and safely at this point (again, thanks to a great mechanic).

Next on my list is to start tackling a few small, slow oil leaks. That said, I noticed a new spot in the last couple of days where oil appears to be coming out of the Neutral Safety Switch. I'm including pictures of where it is, and I'm not even certain that is WHAT it is.

What I want to know is the following:
Is it the Neutral Safety Switch?
If it's leaking oil, is it an easy fix (as in just tightening it a little?) or is there a bigger problem?
Any recommendations on this?

I apologize in advance for any ignorance on my part; I'm just now learning. Also, thanks in advance for any help. I'm not sure why the photos are rotated 90 degrees to the left, but hopefully it's not an issue. :)

V/r,

Travis

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That is the neutral light switch. You need to clean the area thoroughly then dust the area with baby powder or similar. Watch closely after you start the bike and you'll be able to identify whether the leak is around the threads where it screws into the crankcase or is coming up through the switch itself.

Welcome to the group.
 

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Discussion Starter #3
Great; I'll pick up some baby powder and follow up with info/photos. Thanks for pointing me in the appropriate direction and for the welcome.
 

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Welcome to the forum. Great to see another 400 series here.
 

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Discussion Starter #5
Thanks for the welcome; adding to the mystery here. The fluid has gotten hard to the touch as if it were wax or something similar. Also, that cap has fought me and I'm scared I'm going to mess it up trying to pull it off and really clean this thing. I'm attaching a video that perhaps shows the true simplicity that is my mind.

 

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The rubber cover get hard and brittle over time, nothing you can do about it but break t loose. The hard oil could be the PO used Permatex sealer trying to cure the leak. The switch seals to the case using an aluminum washer, possibly tightening it will solve that.
 

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Discussion Starter #8
So I tore this cap off and I think the mystery is solved. I think the PO used some kind of cheap rubber cement to hold the plastic cap on there that, when hot, broke down. When I rode the bike home today I saw that the liquid was again liquid, but it was super sticky. Also, I was able to pull the cap off and it was a darn mess of this cement. Luckily I ordered a replacement cap and I got all that gunk off the top of the neutral light switch. This was fairly anticlimactic, but I did learn a little bit. Thanks, gents!

Trav

p.s. ~ just in case I'm going to watch it now and see if any more develops b/c I have been wrong before (once).
 

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The only way oil can get there is the switch leaking so this sounds like the switch needs replacement.
 

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Discussion Starter #10
Yes, I'm going to watch it and see if oil actually comes out now that the rubber compound or whatever it was is gone. When cold it was rock hard, when hot it was a tacky fluid. I have no idea if it's an easy replacement, but I'm going to watch to see now. :)
 

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It just unscrews after disconnecting the wire. Note that this is a 5 speed trans so you cannot use the 6 speed switch. There is an aluminum washer that seals the switch to the case, no sealer needed.
 

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There is an aluminum washer that seals the switch to the case, no sealer needed.
Do you think the PO lost the washer, lol? Or forgot to remove the old washer before installing the new one :eek: ?

Regards,
 

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Discussion Starter #13
Folks,

After I cleaned the rubber cement off and put a new cap on top I've had zero problems. The integrity of whatever was used to hold the busted cap on was compromised every time it got warm and pieces had fallen out of the cap and looked like a different issue than it was. Thanks for all the help!
 
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