Increasing the sensitivity of in-line brake pressure switches

[DarrenSV650S]

I've got an in-line brake pressure switch because it allows me to remove the standard switch to have the brake lever at a better angle. But people keep telling me they don't see my brake light coming on. It's because there is a bit of travel in the lever before the switch activates.

Is there a way to make the switch come on sooner?

It is normal to have to apply brake pressure before these things come on - normal switches only need the lever to move a bit regardless of whether the brakes are doing anything to slow you down. Personally I dislike the behaviour from pressure switches as I often rest on the brake to activate the light on a trailing throttle in traffic.

Any wear plus the master cylinder piston to resevoir port distance will make a difference to how far the lever travels. If the brakes are properly bled, the switch is not full of gunge and the lever, pivots and master cylinder are in good shape there is little that can be done other than to pull the lever back a little further and a bit sooner. If you have a conventional switch at either end of the bike, you could use that initially to get the brake light going.

Cheers

[DarrenSV650S]

The problem is I'm slowing down with no brake lights on at all. I was thinking there might be something I could do electronically to adjust it. Like putting a resistor in maybe? Or is the switch just a basic push switch?

Unfortunatly with it being a pressure swich it wont be switched until the oil pressure gets to a certain threshold. The only way to make it switch on earlier is to change it for a more sensetive switch or go back to the old setup. Sorry for the news...

Well there is one other way, the brake with a normal switch, this should switch on the brake light before you put any pressure on the actual brake to stop you... So you can just move the lever enough to turn on the brake light but not slow you. So you can do that and with one brake and then actually brake with the other and people will see your brake light. Does that make sense? I often do this just so cars behind me know im slowing, even if it was just engine braking.

[Bibio]

i know it shouldn't matter, but have you tried swapping the wires round?

or i could be you have a slightly defective one, my rear one works no problem as does both of them on my brothers duke.

brakes are a closed system and the switch is like a plunger, so even slowly applying pressure should activate the plunger. another thing it could be is you have a small bubble of air at the switch.

[DarrenSV650S]

Originally Posted by ThEGr33k

Unfortunatly with it being a pressure swich it wont be switched until the oil pressure gets to a certain threshold. The only way to make it switch on earlier is to change it for a more sensetive switch or go back to the old setup. Sorry for the news...

Well there is one other way, the brake with a normal switch, this should switch on the brake light before you put any pressure on the actual brake to stop you... So you can just move the lever enough to turn on the brake light but not slow you. So you can do that and with one brake and then actually brake with the other and people will see your brake light. Does that make sense? I often do this just so cars behind me know im slowing, even if it was just engine braking.

The rear brake has a pressure switch too so that wont work.

Originally Posted by Bibio

i know it shouldn't matter, but have you tried swapping the wires round?

or i could be you have a slightly defective one, my rear one works no problem as does both of them on my brothers duke.

brakes are a closed system and the switch is like a plunger, so even slowly applying pressure should activate the plunger. another thing it could be is you have a small bubble of air at the switch.

Why would the wires matter? The rear one is about the same I think.
What make are yours? Mine are HEL if I remember right.

[Bibio]

mine are goodridge... but i think they are all the same and probably all made in the same factory..

[DarrenSV650S]

Do you think it matters that I am using the sv master cylinder with gsxr callipers?

[Bibio]

nope that should actually help... as there should be more lever travel... so fluid is moving before brakes come on..

have you tried just pulling the brakes on and off for 10 min.. it might loosen up the switch so it reacts quicker.. my brothers front one (double banjo) on the duke was a bit naff to begin with but soon 'bedded in'.

It shouldn't. The switches only needs minimal pressiure. I'd want to verify that the switches are actually working properly by unplugging them and measuring resistance across the pins with the lever pulled and go from there.