Bike stalls when releasing clutch lever?

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Bike stalls when releasing clutch lever?

Postby Leon2021 » 24 May 2021, 13:48

Jest ridden over a 1000 miles on my brand new second hand 1991 zephyr 550
Was ready to go out for another ride today ,
Started up fine letting it warm up all my gear on was about to zoom of only to be disappointed with a stalled engine time after time.
Most disappointed
Any idea?
Clutch had been a bit noisy,an would get quieter with the clutch lever pulled in.
Big thanks in advance for any help given
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Re: Bike stalls when releasing clutch lever?

Postby Stereordinary » 24 May 2021, 16:40

Nice bike! I have the same one. :)

I have had this problem before, though not after so many miles without issue. But in my case the it was a dead spark plug, so the bike was trying to run on three cylinders. It was much better after a fresh set of plugs.
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Re: Bike stalls when releasing clutch lever?

Postby Freddy » 24 May 2021, 21:55

Depends on the definition of 'stalled', but if it means just cuts out completely when the clutch lever is being released and your anticipating just about to start moving ......my first instinct is to say check the side stand switch.

Check the stand actually depresses the switch upon being put up, and that it electrically opens/closes.
Last edited by Freddy on 25 May 2021, 10:12, edited 1 time in total.
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Re: Bike stalls when releasing clutch lever?

Postby Leon2021 » 25 May 2021, 05:46

Thanks Freddy
I will check out the switch on the side stand today.
Will let you know how I get on,Thanks for the reply
Sun is out today so fingers crossed
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Re: Bike stalls when releasing clutch lever?

Postby Freddy » 25 May 2021, 10:25

The key pointer is does the engine (a) completely 100% die, just like the ignition key was turned off ..... or (b) does it sort of keep running, missing and farting etc and eventually die.

If its (a) that's exactly how a faulty side stand switch behaves. The bike thinks the side stand is still down, with the bike in gear and clutch is being released (there is another switch on the clutch lever for that process). It's like the ignition key was just turned off because that's exactly what happens.

In my experience it's often a mechanical fault (rather than electrical, as it a pretty simply on/off switch) where the side stand 'tab' that works the switch is no longer positioned correctly for some reason.
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Re: Bike stalls when releasing clutch lever?

Postby Leon2021 » 25 May 2021, 10:47

Thanks again Freddy
Been out for a blast today ,the side stand switch was dirty so wasn’t going all the way out when the side stand was up,
Cleaned it up and oiled it bingo off I go 3 hour ride before the rain awesome .
Photo of lost ride culprit attached
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Re: Bike stalls when releasing clutch lever?

Postby Freddy » 25 May 2021, 13:55

Good to see it was easily corrected.
Never let anyone every talk you into removing a stand stand switch, because of the odd problem. Seem forums where crew just think its a mandatory modification (along with punching holes in the airbox, makes more noise so it must be running better). They are a worthwhile safety feature.
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