[9216]

Hi,
I have a 2014 Activa i. In its carburettor, there is a tactile switch which gets activated when throttle is opened. A very similar carburettor is in my 1987 cd100, but it doesn't have the switch. Can somebody explain its purpose, please ?
Thanks in advance.

[shancz]

Do you have those economy-power mode indicators on your instrument panel?
If yes then could be that but it's just a wild guess.

[9216]

Originally Posted by shancz

Do you have those economy-power mode indicators on your instrument panel?
If yes then could be that but it's just a wild guess.

No. Only a green mark to show economy range in speedometer.

[anay3000]

If not an auto-choke, then it's a fuel valve. Additional pic from the other side would have helped.

[9216]

Originally Posted by anay3000

If not an auto-choke, then it's a fuel valve. Additional pic from the other side would have helped.

The switch is screwed on to the throttle body and the only interaction is through a small button like projection in to the throttle chamber. When throttle is opened a little from idle position, the upward movement of the valve activates the switch.

Unfortunately, no other pictures are available. There was idling problem while engine is hot. I just cleaned the carburettor thoroughly and everything is fine now. I was just curious as to the function of the switch.

[SS-Traveller]

Originally Posted by 9216

Hi,
I have a 2014 Activa i. In its carburettor, there is a tactile switch which gets activated when throttle is opened
...
Can somebody explain its purpose, please ?
Thanks in advance.

Looks like a fuel shut off valve. Shuts off fuel supply from the float chamber to the main jet when the ignition is off, to prevent engine flooding and / or backfiring.

[anshumandun]

Just 2 days back, I was cruising on Nice Road on my Activa at almost full throttle when suddenly the fuel supply got cut off and the scooter stalled but with enough time for me to move to the side of the road. The scooter won't start after that. But after 5 minutes, the scooter started normally and I covered around 50 kms after that without any issue at all!

I was assuming that probably the engine over-heated and some thermostat did its job to shut down the engine to avoid any damage and once it cooled down, the thermostat reset to make everything work normally.

I don't know if the switch that you discovered has something to do with this, but it might be the safety mechanism that I experienced.

[adrian]

Could be the Throttle Position Sensor (TPS), which is used to induce timing changes with respect to throttle opening.

Like the one in this video

https://www.youtube.com/watch?v=R_4FgKgLIuE

[maheshm619]

Originally Posted by 9216

No. Only a green mark to show economy range in speedometer.

Two ways to get a better idea:

1) The carb model would be embossed on it. For most carbs like Mikuni, you can get detailed drawings online.

2) The part as seen from your pic is held by two screws, take it out and see the internals.

[9216]

This looks like an analog rotational position sensor. The switch in the scooter has only two wires and operates with a single action and has a tactile feel.

[saket77]

Not sure but this could be a throttle position sensor which advances/ retards the ignition timing depending upon the throttle position. In some models & mostly in Bajaj motorcycles, it is a binary switch- either on or off. In most Honda bikes, it is a potentiometer which maps the throttle position throughout the operable range.

[PistonCrown]

I have the same type of carburettor on my 2014 bs3 HET Honda Aviator.

I do not have any economy-power mode or green light to depict it as in economy mode.
My FNG mechanic does not know about it either. Upon disconnecting, the bike also works just fine.

[joednazareth]

Originally Posted by 9216

Hi,
I have a 2014 Activa i. In its carburettor, there is a tactile switch which gets activated when throttle is opened. A very similar carburettor is in my 1987 cd100, but it doesn't have the switch. Can somebody explain its purpose, please ?
Thanks in advance.

Greetings all.
There are two wires that run from this Throttle position switch.
The termination goes to the CDI, to control ignition timing.
Over speed control.
Since this is a gearless scooter and free revving engine.
Disconnect the RED bullet terminal from the switch and
observe the engine linear speed increase.
For Ladies, Retired individuals do not isolate this safety feature.