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Motorcycles » rec.motorcycles.tech » service limit on SV-650 clutch springs
| service limit on SV-650 clutch springs [message #503739] |
Sun, 06 November 2005 06:18 |
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Post removed (X-No-Archive: yes)
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| Re: service limit on SV-650 clutch springs [message #503740 ] |
Sun, 06 November 2005 06:36 |
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Post removed (X-No-Archive: yes)
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| Re: service limit on SV-650 clutch springs [message #503746 ] |
Sun, 06 November 2005 14:38 |
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Gene Cash wrote:
> My '02 Sv-650 is about to turn 40,000 miles, so when I changed the oil,
> I popped the cover off and took a look at the clutch.
>
> I miked the plates and they all seem to be fine. There's also no
> notching on the basket fingers, and the throwout bearing looks good.
>
> However, the manual says the "spring free length service limit" is
> 56.0mm and they're just a hair (maybe 0.1mm) under that.
>
> Is the limit a minimum length?
Yes.
> Does it mean the springs should be at least that length?
Yes.
> Do I need new springs?
Maybe.
> How long are new springs?
Doesn't the manual say what the original length was?
Ummmm, did you ever hear the old saying, "If it ain't broke, don't fix
it"?
Does the clutch slip when you gas it in 4th or 5th gear? If it does,
you need new springs. If it doesn't slip, you can defer maintenance
until it does.
The "spring free length service limit" is the length that the springs
are when they are out of the engine. A coil spring has "memory" of how
long it should be when there is no load applied to it, so it expands
(or contracts, in the case of a tension spring) to that length.
After being compressed for 40K miles inside your engine, the springs
are "sacked out", they've lost some of their strength or "memory"
because the steel molecules have be physically *twisted* out of place.
Twisted? Is that for real? Does that sound weird, or what?
If you had a torsion bar, such as are used instead of coil springs in
automotive suspension systems, the obvious deformation under load would
be the torsion bar twisting.
A coil spring is really a torsion bar that has been formed into a coil.
As you compress it, the obvious deformation of a coil spring is that it
gets shorter. But the inobvious deformation is that the wire in the
spring has to twist for the coil to compress and it has to untwist for
it to rebound.
So a "sacked out" coil spring has been permanently twisted, and has
deformed into a shorter length.
But spring theory (and the well-known spring rate formula) tells us
that the shorter spring is now actually *stiffer* than it was when it
was new. Repeated compressions and extensions could even cause the
spring to break.
And, even though the shortened spring has become stiffer in rate of
load per inch of compression, it may now be so short that it doesn't
push hard enough against the pressure plate to apply enough pressure.
*That's* why the manual specifies a minimum free length.
But you might be able to preload the old, sacked out springs with some
washers if you cannot afford to buy new springs.
Impecunious racers on a budget have been shimming valve springs and
clutch springs for decades. You could theoretically shim the spring
until the coils bind when you tighten the bolts. Of course the clutch
wouldn't *release* when you pulled the lever...
But, if you feel really frisky, you might look around for stiffer
aftermarket racing clutch springs.
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| Re: service limit on SV-650 clutch springs [message #503750 ] |
Sun, 06 November 2005 20:57 |
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Post removed (X-No-Archive: yes)
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| Re: service limit on SV-650 clutch springs [message #503751 ] |
Sun, 06 November 2005 21:50 |
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In article <mzkhpn0x.fsf [at] cfl.rr.com>, Gene Cash <gcash [at] cfl.rr.com>
wrote:
> "skimmer" <rynchops_niger [at] yahoo.com> writes:
>
> > Gene Cash wrote:
> > > My '02 Sv-650 is about to turn 40,000 miles, so when I changed the oil,
> > > I popped the cover off and took a look at the clutch.
> > >
> > > I miked the plates and they all seem to be fine. There's also no
> > > notching on the basket fingers, and the throwout bearing looks good.
> > >
> > > However, the manual says the "spring free length service limit" is
> > > 56.0mm and they're just a hair (maybe 0.1mm) under that.
> > >
> > > Is the limit a minimum length?
> >
> > Yes.
> >
> > > Does it mean the springs should be at least that length?
> >
> > Yes.
> >
> > > Do I need new springs?
> >
> > Maybe.
> >
> > > How long are new springs?
> >
> > Doesn't the manual say what the original length was?
>
> Nope, just the "service limit", otherwise I could tell *for sure* if the
> service limit was a minimum or not.
Do you want to know what the original length was in order to determine
whether the service limit is a maximum or instead a minimum? You can
infer this with fair certainty by considering whether the springs are
used in compression or extension during normal clutch operation. Off the
top of my head, I can't think of a way of using springs in extension in
clutch operation. Furthermore, springs used in extension are _typically_
made with the coils in contact with each other when in the relaxed state.
Therefore, the "service limit" is almost certainly a minimum length, and
not a maximum.
[snip]
> I'll be making sure I have enough of the right kind of oil on hand
> before doing a change.
>
> > Does the clutch slip when you gas it in 4th or 5th gear? If it does,
> > you need new springs. If it doesn't slip, you can defer maintenance
> > until it does.
>
> Actually, the new springs are US$20 for a set, so since I have to order
> the o-ring gasket anyway, and I've already pulled the springs to check
> them, I'll put in new ones. I figured they were far more expensive.
Good plan: simple, cheap, peace of mind, and that's worth something.
Good luck with the install.
--
Later,
John
johajohn [at] indianahoosiers.edu
'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.
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| Re: service limit on SV-650 clutch springs [message #503768 ] |
Mon, 07 November 2005 05:11 |
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"John Johnson" <null [at] invalid.com> wrote in message
news:null-4112B3.15505406112005 [at] newsclstr01.news.prodigy.com...
| In article <mzkhpn0x.fsf [at] cfl.rr.com>, Gene Cash <gcash [at] cfl.rr.com>
| wrote:
|
| > "skimmer" <rynchops_niger [at] yahoo.com> writes:
| >
| > > Gene Cash wrote:
| > > > My '02 Sv-650 is about to turn 40,000 miles, so when I changed the
oil,
| > > > I popped the cover off and took a look at the clutch.
| > > >
| > > > I miked the plates and they all seem to be fine. There's also no
| > > > notching on the basket fingers, and the throwout bearing looks good.
| > > >
| > > > However, the manual says the "spring free length service limit" is
| > > > 56.0mm and they're just a hair (maybe 0.1mm) under that.
| > > >
| > > > Is the limit a minimum length?
| > >
| > > Yes.
| > Actually, the new springs are US$20 for a set, so since I have to order
| > the o-ring gasket anyway, and I've already pulled the springs to check
| > them, I'll put in new ones. I figured they were far more expensive.
|
| Good plan: simple, cheap, peace of mind, and that's worth something.
| Good luck with the install.
is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.
A new set of after-market clutch SPRINGS run $10-$20. New clutch Friction
PLATES run $100ish.
Your Suziki oil, synthetic or 'natural? If synthetic, and you put in
'natural' Castrol, you 'mixed' oil types...
If you want some "Glaze Cleaner Oil", look for some RizLon. I had to
replace the clutch springs in my
Shadow 1100 at 83000 miles. <slip in 5th when you goose it...> Easy to do,
if you CAREFULLY remove
the cover, you can use the gasket again. Plates were well above the service
limit.
I-90 over soqualimie pass, closed due to rock-slides & road damaga.
WA-20 closed due to
Avalance danger. Cover over US-2, or I-84 through the gorge.
asta, Lefty
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| Re: service limit on SV-650 clutch springs [message #507890 ] |
Mon, 07 November 2005 23:37 |
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Lefty wrote:
> Your Suziki oil, synthetic or 'natural? If synthetic, and you put in
> 'natural' Castrol, you 'mixed' oil types...
Which is not a problem and hasn't been for a long time.
Are you any relation to Norm ?
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| Re: service limit on SV-650 clutch springs [message #507951 ] |
Fri, 11 November 2005 02:11 |
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Gene Cash wrote:
> "skimmer" <rynchops_niger [at] yahoo.com> writes:
>
>
>>Gene Cash wrote:
>>
>>>My '02 Sv-650 is about to turn 40,000 miles, so when I changed the oil,
>>>I popped the cover off and took a look at the clutch.
>>>
>>>I miked the plates and they all seem to be fine. There's also no
>>>notching on the basket fingers, and the throwout bearing looks good.
>>>
>>>However, the manual says the "spring free length service limit" is
>>>56.0mm and they're just a hair (maybe 0.1mm) under that.
>>>
>>>Is the limit a minimum length?
>>
>>Yes.
>>
>>
>>>Does it mean the springs should be at least that length?
>>
>>Yes.
>>
>>
>>>Do I need new springs?
>>
>>Maybe.
>>
>>
>>>How long are new springs?
>>
>>Doesn't the manual say what the original length was?
>
>
> Nope, just the "service limit", otherwise I could tell *for sure* if the
> service limit was a minimum or not.
>
>
>>Ummmm, did you ever hear the old saying, "If it ain't broke, don't fix
>>it"?
>
>
> Well, while I'm in there... and it's got nearly 40,000 miles on it. I'm
> happy to say the clutch plates look fine, so there's no flies on my
> shifting technique. :-)
>
> Since the abrupt change in clutch behaviour happened at the same time as
> my last oil change, I think it was because I used automobile Castrol GTX
> instead of the Suzuki motorcycle oil I'd been using. I won't be doing
> that again, but this is the first bike I've had that's complained about
> that. The Castrol is more expensive than the Suzuki, even.
>
> The plates were stuck together pretty well. They all came out of the
> clutch as one piece, except for the #1 plate.
>
> I'll be making sure I have enough of the right kind of oil on hand
> before doing a change.
>
>
>>Does the clutch slip when you gas it in 4th or 5th gear? If it does,
>>you need new springs. If it doesn't slip, you can defer maintenance
>>until it does.
>
>
> Actually, the new springs are US$20 for a set, so since I have to order
> the o-ring gasket anyway, and I've already pulled the springs to check
> them, I'll put in new ones. I figured they were far more expensive.
>
>
>>[nice spring theory deleted - thanks for the info!]
>
>
>>But, if you feel really frisky, you might look around for stiffer
>>aftermarket racing clutch springs.
>
>
> Ohhhhh no, thanks. I've tried that nasty Barnett stuff before on my
> VF750F, and I don't need carpal tunnel.
>
> Thanks for the info.
>
> -gc
>
For serious online info on oil and their derivatives try:
www.Bobistheoilguy.com
Not joking, Got anything from Nasa to high up petro professors on their
forums..
J.
J.
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