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Main Area => General GS500 Discussion => Topic started by: crazyfish on June 28, 2008, 09:52:50 AM

Title: Odd clutch behavior...
Post by: crazyfish on June 28, 2008, 09:52:50 AM
Hey guys,

I was riding along today and the next moment my clutch bite point had slipped in so that the clutch wouldn't properly dis-engage even with the lever all the way in. Needless to say i stalled at the next junction. I pulled over and re-adusted the clutch cable so its all back to normal now. Should I be worried that this is something starting to break? Is there anything in particular i should be checking?

cheers..
Title: Re: Odd clutch behavior...
Post by: ben2go on June 28, 2008, 11:07:48 AM
It maybe time for a new cable.There not much $$$$.Around $12 to $15.
Title: Re: Odd clutch behavior...
Post by: sledge on June 28, 2008, 11:32:20 AM
Maybe the outer cable was not correctly located in one of the adjusters where it enters the crankcase or at the lever, it could easily have happened if the cable has been replaced or adjusted, you wouldn't know it was out of position because the cable ends are hidden underneath shrouds.  If the outer cable end has suddenly clicked home into the correct position this would cause it to immediately slacken off in the way you describe.
Title: Re: Odd clutch behavior...
Post by: ohgood on June 28, 2008, 06:54:02 PM
Quote from: ben2go on June 28, 2008, 11:07:48 AM
It maybe time for a new cable.There not much $$$$.Around $12 to $15.

as always, ben2go is dead right. mine did the same thing a few times, just before it broke last week.

order one now, and find alternative transport until you can replace it. a crappy clutch cable is very very unsafe.

:)
Title: Re: Odd clutch behavior...
Post by: ben2go on June 28, 2008, 08:56:41 PM
Quote from: ohgood on June 28, 2008, 06:54:02 PM
Quote from: ben2go on June 28, 2008, 11:07:48 AM
It maybe time for a new cable.There not much $$$$.Around $12 to $15.

as always, ben2go is dead right. mine did the same thing a few times, just before it broke last week.

order one now, and find alternative transport until you can replace it. a crappy clutch cable is very very unsafe.

:)


Maybe,but I never thought about sledge's response.If I have clutch trouble,1st thing I do is check the adjusters.Make sure the jam nuts haven't let the adjusters vibrate around.That happened to me on a dirt bike and I wrecked.I was young boy and panic.
Title: Re: Odd clutch behavior...
Post by: spc on June 29, 2008, 12:17:50 AM
The scenario sledge described actually happened to me with my GS, so it is very plausible.  Fortunately, I figured it out rather quickly.
Title: Re: Odd clutch behavior...
Post by: crazyfish on June 29, 2008, 03:43:03 PM
I've just ordered a new clutch cable to be safe. Thanks guys...
Title: Re: Odd clutch behavior...
Post by: ben2go on June 29, 2008, 04:11:55 PM
Quote from: crazyfish on June 29, 2008, 03:43:03 PM
I've just ordered a new clutch cable to be safe. Thanks guys...

It's always good to have a spare set of cables.Keeps ya from paying a tow bill.
Title: Re: Odd clutch behavior...
Post by: oobyscoot on June 30, 2008, 07:34:08 AM
Quote from: ohgood on June 28, 2008, 06:54:02 PM
Quote from: ben2go on June 28, 2008, 11:07:48 AM
It maybe time for a new cable.There not much $$$$.Around $12 to $15.

as always, ben2go is dead right. mine did the same thing a few times, just before it broke last week.

order one now, and find alternative transport until you can replace it. a crappy clutch cable is very very unsafe.

:)

Yep, same thing on me old Kwack. New cable time.

Before you fit the new cable, fill it with oil. Hang it overnight and make sure the outer is full with oil before fitting, it will last loads longer.
Title: Re: Odd clutch behavior...
Post by: sledge on June 30, 2008, 12:04:44 PM
Quote from: oobyscoot on June 30, 2008, 07:34:08 AM
Quote from: ohgood on June 28, 2008, 06:54:02 PM
Quote from: ben2go on June 28, 2008, 11:07:48 AM
It maybe time for a new cable.There not much $$$$.Around $12 to $15.

as always, ben2go is dead right. mine did the same thing a few times, just before it broke last week.

order one now, and find alternative transport until you can replace it. a crappy clutch cable is very very unsafe.

:)

Yep, same thing on me old Kwack. New cable time.

Before you fit the new cable, fill it with oil. Hang it overnight and make sure the outer is full with oil before fitting, it will last loads longer.


How does an inner clutch cable suddenly "Grow" by the extra 1/2" or so needed to cause enough free-play to stop the clutch pulling in??      anyone??    :dunno_white:

With time and use all cables stretch by a small amount...............but they dont instantly stretch by 1/2"  :laugh:
Title: Re: Odd clutch behavior...
Post by: beRto on June 30, 2008, 12:23:13 PM
Quote from: sledge on June 30, 2008, 12:04:44 PM
How does an inner clutch cable suddenly "Grow" by the extra 1/2" or so needed to cause enough free-play to stop the clutch pulling in??      anyone??    :dunno_white:

With time and use all cables stretch by a small amount...............but they dont instantly stretch by 1/2"  :laugh:

Perhaps the material has reached its fatigue limit? I thought fatigue resulted in brittle failure, but it may be possible that yielding is occurring instead. :dunno_white: 

This wikipedia article has some information which may-or-may-not be relevant:
http://en.wikipedia.org/wiki/Deformation_%28engineering%29#Metal_fatigue
Title: Re: Odd clutch behavior...
Post by: ben2go on June 30, 2008, 01:05:01 PM
I have had cables stretch more frequently when they're new.Have to readjust a couple times.Then it's like once a year,more or less,depending on the use and abuse.
Title: Re: Odd clutch behavior...
Post by: sledge on June 30, 2008, 03:49:16 PM
Quote from: beRto on June 30, 2008, 12:23:13 PM
Quote from: sledge on June 30, 2008, 12:04:44 PM
How does an inner clutch cable suddenly "Grow" by the extra 1/2" or so needed to cause enough free-play to stop the clutch pulling in??      anyone??    :dunno_white:

With time and use all cables stretch by a small amount...............but they dont instantly stretch by 1/2"  :laugh:

Perhaps the material has reached its fatigue limit? I thought fatigue resulted in brittle failure, but it may be possible that yielding is occurring instead. :dunno_white: 

This wikipedia article has some information which may-or-may-not be relevant:
http://en.wikipedia.org/wiki/Deformation_%28engineering%29#Metal_fatigue

Every component in use thats subject to varying stresses/strain has a finite life. Cables are no different, assuming perfect operating conditions the lifespan is dependent on the amount they stretch. This stretch is proportional to the amount of load and the number of cycles they see. A cycle being a period of tension followed by a period in a unstressed state, the more load or the more cycles they are subject too the more they stretch until (if allowed too) the elastic limit is reached and they fail...... (See Hookes law).

A tiny amount of stretch in use is normal over time, its one of the reasons why there are adjusters provided in the system. However If anyone wants to believe that cables can and do suddenly and instantly stretch by amounts significant enough to prevent proper function of the clutch without the cable failing.....well, I guess thats your perogative. Quoting Yeild limits, stress, strain and fatigue equations, Youngs modulus, elastic limits, Poissons etc etc are all very well......but the cable will have been designed and engineered by people with all these factors in mind and the upshot is..........it just doesnt happen.

BTW....... if anyone does know how to dramaticaly increase the elastic properties of cold-drawn mild-steel please PM me because I have contacts and know the right people who can make us very rich, very quickly  :thumb:
Title: Re: Odd clutch behavior...
Post by: GeeP on June 30, 2008, 05:56:11 PM
A wire rope can't be compared to a contiguous bar insofar as failure analysis is concerned.

A twisted steel cable does not behave the same as a single steel unit under tension due to strand packing.  As the cable takes on stress, the strands pack inwards, causing an increase in cable length.   

In the case of corrosion fatigue failure, the cable will generally fail from the outside in.  A lubrication breakdown will cause the cable to fail from the inside out.  Regardless, as a few weakened strands fail, it is possible for a sudden increase in cable strain that may not result in a severing failure depending on the loads applied.  Obviously, the safety factor of the cable comes into play here.  Regardless, the usual failure mode at loads well below the cable's ultimate strength is a partial failure that results in a sudden increase in cable length.

Obviously, if a new cable were tested to ultimate load, the failure would begin with  few short strands failing aka "the warning click" followed by a severing failure.  However, a worn cable operated below the proportional limit of the material will not fail in the same manner as a solid round section.