Clutch problem with Suzuki GS 450 1988 please help

Discussion in 'Motorbike Technical Discussion' started by vasco, Oct 3, 2005.

  1. vasco

    vasco Guest

    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.


    - 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.

    Vasco Calais Pedro
    vasco, Oct 3, 2005
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  2. vasco

    monk Guest

    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.
    monk, Oct 3, 2005
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  3. 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 and register so you can look at the
    transmission and shifter shaft fiches to follow what I'm going to tell

    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

    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

    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

    Since you can get into 4th gear and it stays there, but you can't get
    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

    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

    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,
    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.
    krusty kritter, Oct 3, 2005
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