Topic: Neutral light will not go off even in gear - help please.

[Magpie]

This is in a 1977 CB750F, I have replaced the neutral switch with a NOS one, light stays on, replaced the NOS one with another one, light stays on. So the neutral switch circuit is getting powered all the time? The wiring in the headlight seems right. Any help or thoughts what's going on? Thanks.

[HondaMan]

It sounds like the Neutral Switch isn't fully seated. This can also make Neutral really hard to find, the drum just wants to turn past it easily.
The best way I know to seat them is to have the engine in Neutral, look up into the hole where this switch goes, and make sure that you cannot see the shoulder of the shifter drum. They can slip outward, toward the outside of the engine, when the switch is left out for a period of time, especially if a shift was attempted with the switch out, or not fully seated.

Install the new 3x18 O-ring into the groove, then oil it up (or even grease it up) to help to let the switch body slide in easier.

[Magpie]

Thanks. I will take the switch out and have a look up the hole. I have changed the gears with the switch out. The light had stayed on just after a ride. I'll try to move the drum towards the inside of the motor. The switch is fully seated. I'll report in what happens.

[BenelliSEI]

Remember the neutral switch sends a ground to the lamp....... Confirm the obvious first: make sure the wire is not grounding somewhere else. When you take the wire OFF the switch, does the lamp go out? If it does, focus on the switch.

[Magpie]

The light goes off when the wire is off. I'm thinking it may involve what Hondaman mentioned about the shift drum.

[BenelliSEI]

Having tested the wire, I agree! Good luck.

[Jerry Rxman Griffin aka MuthaF'er]

Try this, loosen the retainer bolt for the neutral switch, remove the shifter side cover, wiggle the "cage like" external part of the drum in and out. See if this helps seat the switch. Worked for me.

[Magpie]

Thanks Jerry, will do that shortly.

[Magpie]

All right - got it! Thanks for all your input. I tested the switch and wiring by taking the switch out, touching to ground and pushing down on the ball on the top of it and the neutral light went out, so that system worked. I finally found that the dimple in the shifter drum was not lining up with the ball on top of the neutral switch. By getting the bike up high enough I could get a look up the hole to see the drum and the dimple. By taking off the shifter cover (thanks Jerry) I could see that when the shifter mechanism showed neutral, the dimple in the drum was not able to line up with the ball on the neutral switch. By using the shifter I could get the dimple facing straight down thus lining up with the neutral switch ball. The neutral switch would bottom properly in it's hole now. Thanks HondaMan, you've done it again. Now it will stay that way with any luck. On to the next project. Cheers, Cliff.

[HondaMan]

Good job, and thanks to Jerry!