Dealing with the Kill Switch When Replacing the Throttle Housing on an SR400 (Type 3)
On the disc-brake SR400 (Type 3), removing the stock throttle housing stops the engine from starting. We explain how the kill switch causes this and how to fix it without cutting the harness.
- Why a Type 3 SR won't start once the stock throttle housing is removed
- What the switches on the stock housing do
- A connector-based fix that avoids cutting the stock harness
- Connector differences by model year
How to install an AMAL throttle housing is covered in HANDLE PARTS Chapter#03, but on some models the switches on the stock throttle require one extra step.
The typical example is the newer disc-brake SR, known as the Type 3. If you simply remove the stock throttle housing, the engine won't start.
01 The catch when replacing the throttle housing
Replacing the stock throttle housing with an aftermarket one is a classic custom, but on the Type 3 SR, the key is how you deal with the wiring of the switches on the housing.
02 The cause: a change to the kill switch
The stock throttle housing carries two switches: the kill switch and hazard switch. Removing the hazard switch doesn't affect riding, so you can leave it as is.
The problem is the kill switch. On earlier models, the circuit was internally OFF when the switch was in the ON position, so you could remove the whole housing without trouble. From the Type 3 on, however, the switch is internally ON in the ON position.
When removing the throttle housing on a Type 3, the kill switch circuit must be kept in the ON state. Otherwise the engine won't start.
03 A fix that avoids cutting the harness
Cutting the wires and connecting them directly works fine functionally. But many people would rather not cut the stock harness if they can help it. That's why we recommend a method using a connector.
All you need is a 6P 110-type female connector with the two terminals in its left column jumpered together. Simply plug it into the red connector left after removing the throttle housing side.
On SRs from 2002 onward, the connectors and bullet terminals are the 090 type, so the 110 type can't be used. Check your bike's model year and connector type before getting the parts.
What we used
- 6P 110-type connector (female)
- Wire for jumpering the terminals
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*Installation is at your own risk. If you're unsure about doing the work yourself, we recommend consulting your local motorcycle shop.
*The content and photos reflect the time of writing. Please check each product page for current specifications, fitment and stock.