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TLOTM Sept. '08
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1,629 Posts
Discussion Starter #1
SteveTLS has long advocated against bypassing the clutch switch directly, that I know quite a few have done

Here's the story and the supporting evidence (courtesy of Steve's site) - click on the video link for visual demonstration.

I came across this today on the HealTech GIPro site as further supporting evidence:



Bottom line - DON'T bypass your clutch switch!

(or if you feel you have to, ensure that you follow the method shown in Steve's instruction and cut the wire to the ECM)
 

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TLOTM Sept. '08
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1,629 Posts
Discussion Starter #2
Safe Clutch Switch bypass

As first (I believe) identified by SteveTLS,( http://wotid.com/tls/content/view/18/56/ ) the clutch switch provides more information than just an interlock for the starter.
It also provides an input to the ECM which selects different map (this was further validated by the guys hacking the ECM)

Actually Suzuki uses this feature on all its FI systems.
So it is important that you do not simply jumper out the wires to the clutch switch in order to bypass the clutch switch (so that lever does not have to be pulled in)
Shorting the switch permanently has negative consequences for 'normal' running - some are obvious and others may be more subtle.

For example on the SV650, it has a pronounced effect on gas mileage and you can see the effect of the switch on the injector pulse signal

(Image from TeeRiver published on SVRider)



On a GSXR it makes a significant different to the power output!

(Image from EDR Performance published on WERA forums)



Convinced? :devious

Bottom Line - not a good idea to just jumper out the switch!
Personally, I am not at all inconvenienced by it, but a lot of people seem to not want to have to pull in the lever. So here is safe work-around.

You have a couple of options:

1: You can jumper out the switch but cut the input at the ECM so that it does not see the 'permanent' clutch shorted condition
The downside is that the enhanced starting map will never be selected either.

2. Connect a relay across the switch.
This has the bonus of still temporarily selecting the appropriate enhanced starting map, while removing the requirement to actually pull in the lever.

Here is option 2:



As indicated, you can either connect this at the front/headlight harness, or directly at the starter relay itself. The wire colours are same at either location on both the TLS and TLR.

The signal starter button itself is what energizes the bypass relay.

Very simple mod to incorporate if you feel you really must have that bypass.

.
 

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TLOTM Sept. '08
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1,629 Posts
Discussion Starter #3
Update:

In the course of this thread identified (with SteveTLS input) that when the ECM sees the Start and Clutch signals together, it starts the pump run: so if the other suggested bypass option (bridge switch and cut ECM clutch input) is adopted, the pump won't actually re-start until it sees a number of crank revolutions.
So in order to get instant pump run when starter is operated, the relay is the ONLY way to accommodate the exact replication of the intended control scheme when you want to bypass the clutch switch. It may make a difference in starting vs cutting the wire (although it will likely still start ultimately)

I still say, unless you have some real critical need to eliminate pulling in the clutch, easier to just to leave std switch in play!

.
 
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