'91 Nighthawk 750 neutral switch question

dkruitz

dkruitz

Joined
Aug 6, 2015
Messages
314
Location
Peoria, Illinois
Bike
1995 ST1100
Just throwing this out there in case someone with knowledge has an idea.

I'm helping my brother-in-law get his new project '91 CB750 running. We've redone the carbs, are working on the tank, fixed a valve cover gasket leak, but the biggest issue now is it appears the neutral switch is acting up.

We haven't torn into it just yet and I wonder if anyone knows if the switch is serviceable or adjustable? Or do we just get a new replacement from Honda?
 
IIRC does also the Nighthawk have the diode in the neutral/sidestand/clutch-switch safety circuit, so I'd give that a check as well.
 
Sometimes it works sometimes not. When it's not working you have to start it with the side-stand up even if it's in neutral.
 
I have seen in print that the side stand switch has been a problem area. After sitting for 8 yrs. it wouldn't surprise me that yours is intermittent. You should be able to test operation with a multimeter. If the meter indicates intermittent behavior, see if the switch can be non-destructively disassembled. I believe what you'll find is a simple rotating wiper that is either open or closed electrically, depending on position. Clean any crud, apply a dab of grease and reassemble. You've got nothing to lose.

Good Ridin'
slmjim
 
I can't remember if the later Nighthawks had the same problem as the earlier ones, but on mine that switch/sensor/diode/device thingy is under a cover on the left side of the engine. There's a plunger that runs through a little O-ring and into the clutch assembly itself. When that O-ring gets older or gets disturbed, it will weep a little oil into the area under that cover which will mess with the sensor. Sometimes, just opening that cover and cleaning the oil off the sensor and out of the area under the cover is enough to correct the problem. Temporarily, anyway. The beauty of my older model Nighthawk is... NO kickstand switch!
 
Thanks guys, it's been put on the back burner as we got other issues worked out. There's a pair of large #3 JIS screws holding it in place and of course the 2nd one won't budge. Hoping repeated heat cycles and penetrating oil help loosen it up so we can get it off to inspect.

Bike is running well now and oh, found out the rear shocks aren't rebounding. Seems like it's always something, but we are crossing things off one by one at least. :)
 
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