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TLOTM Sept. '08
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Discussion Starter #1
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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:thumbup
 

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:stupid

Nice bit of research there D :thumbup Just goes to show that if you don't know what your doing just leave it alone, you might just be doing more harm than good.:O
 

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TLOTM Sept. '08
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Discussion Starter #6
... Nice bit of research there D ...
My part is minimal really!
As indicated in initial post, research credit goes to Steve - he's the one from whom I first learned about this.
The data is just additional reinforcer for those still in any doubt.

The Relay is just a simple work-around I provided for the SV guys, so thought that how-to & a reminder again over here might be worthwhile;
the relay solution is just a little different offering from what has gone before (at least to my knowledge).
A solid state switch (transistor) was consideration but most people can handle wiring a relay.
 

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Upside Down Super Mod,
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Excellent work (as usual).

Does the ECU need the clutch switch input for starting as when you're in neutral it seems to make no difference anyway? :dunno

The ECU still gets the start signal from the starter button (the Y/G wire, ECU input STA) when you press it so it knows you're trying to start it. (Also how it know whether to throw a crank and or cam sensor fault code I gather - i.e gets the start signal, but sees no pulses from the sensors).

Now we need a scope and see what happens when the STA is taken high with a running engine;)
 

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TLOTM Sept. '08
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Discussion Starter #8
... Does the ECU need the clutch switch input for starting as when you're in neutral it seems to make no difference anyway? :dunno....
I was thinking same thing earlier today - there could be an (effective) 'OR' gate on the clutch or start to enable the same map?
Obviously that would allow the start map to be engaged if the bike was in gear (stalled for example) and clutch pulled to allow it to start.
If it really doesn't matter, the simpler solution is just to clip the wire at the ECM.
But do we know that the start switch actually sets the map or just the function you mentioned?
It is conceivable - and seems intuitive that it might also trigger the start map - but is somewhat speculative until someone can validate - maybe its all on the clutch.
I really don't know. Maybe our hackers can decipher?
So who knows how all the logic is tied in - there may be other subtleties. :confused
So I figured regardless, the relay covers the bases and replicates the original scenarios all round.
 

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Upside Down Super Mod,
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So I figured regardless, the relay covers the bases and replicates the original scenarios all round.
And that it does. :yes
 

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That mirco switch has a limited life span before the internal contacts get pitted.
It is worth replacing even as soon as 40000 kms as preventative maintenance. ..(fwiw)
 

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my TLS doesn't need the clutch pulled to start. It was like that when I bought it.
How can I check which part has been disconnected in mine.
I have two black wires with yellow tracer, coming from the inside of the left switch gear to a two pin black plug. Its just hanging from my bars and is taped up.
Is this bypassing my need to pull in the lever to start? if so, where should it plug into?
 

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TLOTM Sept. '08
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Discussion Starter #16
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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After checking into this, I have also realised my lever doesn't even have the switch the plug goes into.
Would this be a very noticeable difference, my bike runs great, starts first time, and pulls the front wheel off the floor in first through 3rd.
 

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Wow!
Really good info. Thanks for posting it. This saves me the trouble of sourcing a switch to suit my Brembo clutch master cylinder.
Guess what I am doing this weekend... :hail
 

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Heres what i have noticed on my bike.
When on cold map, bike running and in gear, When i release the clutch, the rpm's raise with aprox 1000-1500 rpm's.
I think i does this to aid launch of the bike.
But if you do the relaymod, it probably will stay up in the 2500 rpm' area.

Won't that be a problem. Especially with adjusting the idle???
 
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