misfire with clutch switch activation?

Vince · Post by **Vince** » Sun Sep 01, 2013 8:22 pm

Here's one for the collective...
I've complained to my dealer about a misfire, when I change gear, mostly felt in the lower three gears, up and down the box.
Unfortunately, test rides by techs and service personall seemed unable to detect/replicate it.
The bike had this from when I bought it with 5000 miles on.
It's a very small misfire, but spoils the ride for me.
At the 78,000 mile service which were fitted a set of platinum plugs, the misfire disapears. Bliss, a smooth ride and gear change hairpins are a joy.

however, plugs were a red herring.
My bike has had an issue with not starting in gear with clutch lever pulled in for quite some time, however I think it was intermittent.
Now it turns out there is a connection between clutch switch and misfire.
Cause of not starting in gear was eventually traced to worn clutch lever pivot pin. New pin cured the non start in gear. However, when I picked the bike up my misfire had returned which got me thinking.
This weekend I tested my theory that for some reason, when the clutch switch is actvated on the release it causes a slight misfire. I proved this at the weekend by disconnecting the clutch switch at the plug under the tank, misfire not present. reconnect plug, bike misfires on clutch lever activation. I repeated the test with same results.
So, why does it do it and how to cure it.
currently I have just left it disconnected, but would like the start in gear and cruise interlock to be working.
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slparry · Post by **slparry** » Sun Sep 01, 2013 9:20 pm

could there also be an issue with the side stand switch as it kind of interconnects with the clutch switch?

Boxered · Post by **Boxered** » Sun Sep 01, 2013 10:44 pm

As Steve says, disconnect the side stand switch and see if you can replicate the error?

Steve

Vince · Post by **Vince** » Mon Sep 02, 2013 11:25 am

Thanks for the replies.
I'll take a look at the side stand and test.

I have tried wiggling the stand about while it's in gear and running with no misfire so kinda eliminated that from the equation. However, perhaps I should re connect to clutch switch and disconnect the stand switch go ride and see what hapends.

I can actually replicate the tiny misfire, right at the point the clutch micro switch connects by changing from say 2nd to 3rd, letting the clutch out so it just starting to bite, but hasn't activated the switch. So I have some drive, the bike is just pulling, all backlash in drive train is backed up one way, then as I let the clutch out a tiny bit more the switch is triggered and the misfire (only one) will occur, I can actually play the lever back and forth just a tiny amount which must be opening/closing the switch and get a repeated misfire. Almost like the ECU has paused the injectors for a fraction of a second. It is really quite subtle and short but buggers the harmony of the ride up for me.
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Dai wiskers · Post by **Dai wiskers** » Mon Sep 02, 2013 11:37 am

Try soaking the micro switches with wd 40 or preferably a very light aerosol lubricant 3in1 etc
Many people use a heavy lubricant (chain lube) to lubricate levers this clogs the micro switches and needs flushing out really soak them don't just give them a quick spray

Hope this helps Dai

Vince · Post by **Vince** » Mon Sep 02, 2013 11:47 am

Thanks Dai.
The switches are working fine though, it's the fact the ECU seems to think it should cut some fuel or power when they activate that's the issue.

I personally know one guy that had the same issue on a GS12's and he sold it in the end as his dealer in Germany could not find an the fault. His new GS12 (2010) doesn't have a problem so he's happy.
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Droptarotter · Post by **Droptarotter** » Mon Sep 02, 2013 4:51 pm

Vince;
Are you sure the clutch switch is working fine?

The reason I ask is.......I was chasing a stalling problem on my 12S......I could hear the clutch switch "switching", but when I hooked up my GS-911.........I could see that the clutch switch was only working intermittently.
The GS-911 software shows real time values and indicates if the switches are open or closed.

I swapped the clutch switch with the front brake light switch and that eliminated my stalling problem.

So then I just replaced the front brake light switch.

Cheers

oyster · Post by **oyster** » Mon Sep 02, 2013 5:37 pm

I suggest fitting a new clutch switch for peace of mind.

Vince · Post by **Vince** » Mon Sep 02, 2013 6:43 pm

Thanks for the input,
New clutch switch was fitted as part of the fault finding prior to finding the clutch lever pivot pin was the culpret.
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boxerscott · Post by **boxerscott** » Mon Sep 02, 2013 7:52 pm

Check the clutch switch harness, (if it is a separate component) also check the connectors for clean contact. I have had harness issues with boilers they bell out ok but wont carry voltage required for clean contact Is there a faulty neutral switch?

Vince · Post by **Vince** » Mon Sep 02, 2013 8:45 pm

Thank you for the suggestion.
We've bottomed out poor contacts and wiring loom when they spent 5 hours trying to figure out why it wouldn't start in gear with lever pulled in but the computer could speak to the working clutch switch.

The issue appears to be that because the clutch switch is actually working, and a signal is being seen by the ECU.This appears to cause some other anomaly and cut spark or (in my opinion) an interuption in injector pulse.

The fact this bike has done it since I had the bike at 5k miles and is still the same some 83k later (unlrss I disconnect the clutch switch) leads me to believe it's a fault in the ECU, or the program within.

But I welcome all your ideas before I just fit an inhibiting switch in line with the clutch switch.

One other strange thing, I decided to have the clutch switch looked at as
1. It didn't start in gear with clutch lever pulled and,
2. The cruise stopped working on my last trip to France, so thought the switch or loom was the issue.
The new clutch lever pivot pin fixed both these but at the moment the cruise still works with the clutch switch disconnected. obviously it won't disengage the cruise when I pull the lever but I'm puzzled by the inconsistency .
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Dai wiskers · Post by **Dai wiskers** » Mon Sep 02, 2013 8:58 pm

Could the new clutch switch have been damaged before you replaced the pivot pin

Vince · Post by **Vince** » Mon Sep 02, 2013 9:14 pm

I appreciate the thought, but the switch is working. Proved my the misfire when its plugged back in and switched, also by the working start in gear and cruise disengage as it should when I pull the lever.

The issue to my mind is that the signal received by the ECU when the clutch switch is opening or closing (I'm not sure whether the switch is open or closed on lever release) causes the ECU to interupt some other system.

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boxerscott · Post by **boxerscott** » Thu Sep 05, 2013 8:09 pm

I think it is not unreasonable to suspect the ECU. Might the chip be causing this? Swap it?

Vince · Post by **Vince** » Thu Sep 05, 2013 8:47 pm

Is it possible to change the chip on the 1200?

Although I did spend £360 on a remap which I'm loathe to lose as it does bring the bike alive.
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