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Motorcycles » rec.motorcycles.tech » Clutch problem with Suzuki GS 450 1988 please help
| Clutch problem with Suzuki GS 450 1988 please help [message #460886] |
Mon, 03 October 2005 02:13 |
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Hello all,
After declaring that I had finished fixing an old bike (Removed the
rust, replaced bent handle bar, replaced bent gear shifter lever,
replaced a few other minor parts) and ready to go out riding in a
beautiful sunny day, I found out that I wasn't able to shif gears. I
followed the clutch adjustment procedure described in the manuals
several times, adjusted the cables several times, but the best I get is
having hte gears working properly for a minute before I am unable to
shift gears. Furthermore, most of the times, with the bike running, as
soon as I try to go from neutral to 1st the bike dies immediatly. Any
ideas what could it be? I would hate to start disassembling the whole
clutch just to find out that there is a spring somewhere or some
adjustment that I need to make.
Symptoms:
- Very difficult or impossible to change gears, even after the cables
where adjusted
- After clutch adjustment, sometimes gear shifting works for a minutoe,
only to return to problem.
- The bike dies when trying to go from neutral to 1st.
- Even when the gears work, can't get above 4th gear.
Any help would be appreciated. This seems to be the last hurdle before
some nice riding sessions.
Thanks,
Vasco Calais Pedro
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| Re: Clutch problem with Suzuki GS 450 1988 please help [message #460887 ] |
Mon, 03 October 2005 03:16 |
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not sure on the particular clutch on this bike, but on the RD350 I'm
working on, had troubles like this. The clutch plates were sticking
together from old oil and sitting in a barn for too long. I took off
the clutch cover and separated the plates by hand (with the clutch
pulled in) and poured fresh oil over them. Reassembles the case and
filled the engine with fresh oil. Problem resolved. May be the same
for you.
On 2 Oct 2005 17:13:13 -0700, "vasco" <vpedro [at] gmail.com> wrote:
>Hello all,
>
> After declaring that I had finished fixing an old bike (Removed the
>rust, replaced bent handle bar, replaced bent gear shifter lever,
>replaced a few other minor parts) and ready to go out riding in a
>beautiful sunny day, I found out that I wasn't able to shif gears. I
>followed the clutch adjustment procedure described in the manuals
>several times, adjusted the cables several times, but the best I get is
>having hte gears working properly for a minute before I am unable to
>shift gears. Furthermore, most of the times, with the bike running, as
>soon as I try to go from neutral to 1st the bike dies immediatly. Any
>ideas what could it be? I would hate to start disassembling the whole
>clutch just to find out that there is a spring somewhere or some
>adjustment that I need to make.
>
>Symptoms:
>
>- Very difficult or impossible to change gears, even after the cables
>where adjusted
>- After clutch adjustment, sometimes gear shifting works for a minutoe,
>only to return to problem.
>- The bike dies when trying to go from neutral to 1st.
>- Even when the gears work, can't get above 4th gear.
>
>Any help would be appreciated. This seems to be the last hurdle before
>some nice riding sessions.
>
>Thanks,
>Vasco Calais Pedro
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| Re: Clutch problem with Suzuki GS 450 1988 please help [message #460890 ] |
Mon, 03 October 2005 05:20 |
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vasco wrote:
> I found out that I wasn't able to shif gears. I
> followed the clutch adjustment procedure described in the manuals
> several times, adjusted the cables several times, but the best I get is
> having hte gears working properly for a minute before I am unable to
> shift gears. Furthermore, most of the times, with the bike running, as
> soon as I try to go from neutral to 1st the bike dies immediatly. Any
> ideas what could it be? I would hate to start disassembling the whole
> clutch just to find out that there is a spring somewhere or some
> adjustment that I need to make.
>
> Symptoms:
>
> - Very difficult or impossible to change gears, even after the cables
> where adjusted
> - After clutch adjustment, sometimes gear shifting works for a minutoe,
> only to return to problem.
> - The bike dies when trying to go from neutral to 1st.
> - Even when the gears work, can't get above 4th gear.
Well, I would necessarily jump to the conclusion that it's a clutch
problem if you can't get into 5th gear. And the part about the engine
dying when you try to go into first gear just might be dirty idle jets.
I won't go into that because I've written a book in this NG talking
about cleaning jets.
You can go to www.partsfish.com and register so you can look at the
transmission and shifter shaft fiches to follow what I'm going to tell
you.
ALL of the gears in a motorcycle transmission a meshed all the time,
that's why it's called a "constant mesh gear box". So, what actually
engages the gears? Some of them slide sideways and metal pegs called
"dogs" slide into slots on the gears next to them and you're in some
gear.
So, in order to move the gears sideways, you have a rotating cylinder
called a "shifter drum" and there is a mickey mouse linkage attached to
the end of the shifter drum and that turns the drum. There are weird
grooves on the shifter drum and there are shifter forks that follow the
weird grooves as the shifter drum turns and the shifter forks push the
gears sideways, engaging one gear and disengaging another gear (or
going into neutral).
And, there is a multi-lobed cam on the end of the shifter drum that is
part of the gear detent system. The other part of the detent system is
either a ball and spring or and arm with a roller on the end that drops
into one of the valleys between the lobes of the multi-lobed cam.
Sometimes that cam is called a "star wheel". If you didn't have the
gear detent system, the transmission would not stay in the gear you
selected.
So, what can go wrong with a motorbike that has set around for a long
time with nobody riding it? The oil can get all gooey and make the
clutch plates stick together, as monk said in another post, but the
gooey thick oil can also keep the gears from sliding freely on their
shafts.
Since you can get into 4th gear and it stays there, but you can't get
into
5th gear, that suggests that the shifter drum is turning and that the
detent mechanism is working, so there are three things that might be a
problem.
One is the gooey oil I mentioned (or rust on the transmission shaft)
and another is that one of the shifter forks was bent by a previous
owner, and the last one is the circlips that locate the gears on the
shafts in the transmission. I once assembled an engine with loose,
floppy circlips on the shaft and I thought it didn't make any
difference.
But, when I tried to shift into 5th gear, one gear would just move
sideways, away from the gear that was being pushed at it.
The easiest thing to do is to put the bike up on the centerstand and
turn the rear wheel by hand while you work the shift lever through all
the gears. If it's just goop or rust on the transmission shafts, you
make be able to loosen up the transmission and make it shift.
But, if the problem is the shifter forks or the circlips, that's bad,
the
engine will have to be removed from the frame and the cases split to
get into the transmission. And your old Suzuki may not be worth the
effort, but that's up to you.
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