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  1. #1

    Question Different SVHO Clutch question

    Hey,
    Could be a dumb question but its the only way to learn
    Looking for a bit more info about these clutches (I have searched but might have missed it) as some seem to not last long and the more info about them pre failure the better.

    So to start
    Got a gp1800 50hrs with following mods, ribbon delete, intercooler, intake, exhaust, 13/18 solas, worx intake grate and riva ride plate with 8650 vetch tune hitting about 7900rpm at 77ish mph (Should be faster, somethings wrong)

    After checking everything got around to checking the clutch and noticed that it spins freely one way as it should. When I go to spin the other way it has hard resistance(Not spongy). So far so good.
    Now for the question. When I put a little bit of pressure against it, it feels like it pops into place and then it wont freely move in either direction it's locked into place, to free it I must put pressure on it the other way then it will spin freely again (One way).
    So if I push against the resistance of the clutch it locks. So is this normal operation of the clutch? If so ill keep looking for the cause of low rpm.

    Supercharger is off by the way so has nothing to do with wheel/shaft. And all the teeth on all the gears look great.

    If anyone could shed some light on this would be great
    Thanks in Advance


  2. #2
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by XistanceX View Post
    ...
    Got a gp1800 50hrs with following mods, ribbon delete, intercooler, intake, exhaust, 13/18 solas, worx intake grate and riva ride plate with 8650 vetch tune hitting about 7900rpm at 77ish mph (Should be faster, somethings wrong)

    ...
    Which Vtech tune, exactly?

    What octane gasoline is the tune set for?

  3. #3
    Hurricane1000's Avatar
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    Quote Originally Posted by K447 View Post
    Which Vtech tune, exactly?

    What octane gasoline is the tune set for?
    Check for a boost leak....possibly leaking at the throttle body mount....you might not have gotten the boost pipe on there all the way....
    You can buy the billet mount in the online store......

    I would also buy a billet R&D supercharger shaft and pin the supercharger housing...
    Jerry has a video explaining all of the mods for the GP1800...

    These are common methods for reliability for the SVHO Yamahas.

    Dave

  4. #4

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    The spin test will definitely indicate a totally blown clutch, but may not a slightly slipping one. The best indicator is to have a boost gauge, which is also helpful to trouble shoot other issues like boost leaks in the piping. You may want to check the BOV also.
    The clutch is not quite like most people would picture, it is actually a set of roller bearings set in an angled cage which kinda is like a ratchet, spins one way easy but friction locks the other. As these bearings wear, they begin to not hold as well, then will finally self destruct as the wear accelerates from increased slipping. Yamaha has improved/changed the design a few times over the years and they are definitely better, but still suffer when abused. (Abuse meaning higher than stock boost levels, higher rpm's, and compressor surging from rapid throttle releasing at high boost without a relief for the air already moving at a high rate stalling in the supercharger and pushing back on the turbine, stressing the clutch).

  5. #5
    Quote Originally Posted by K447 View Post
    Which Vtech tune, exactly?

    What octane gasoline is the tune set for?
    I originally had the stage 1 8650 tune changed to 8400. So my maptuner now reads Stage 1 8400 Stage 2 8650 Stage 3 9200.

    As far as octane i always run 93 no idea what the tunes set to. I have asked whats required for each stage, just waiting for a reply.

  6. #6
    Quote Originally Posted by Hurricane1000 View Post
    Check for a boost leak....possibly leaking at the throttle body mount....you might not have gotten the boost pipe on there all the way....
    You can buy the billet mount in the online store......

    I would also buy a billet R&D supercharger shaft and pin the supercharger housing...
    Jerry has a video explaining all of the mods for the GP1800...

    These are common methods for reliability for the SVHO Yamahas.

    Dave
    Supercharger is pinned, will do the shaft when i upgrade the wheel

    I will put everything back together when i get a chance to check for boost leaks again. Have checked already but may have missed it.

  7. #7
    Quote Originally Posted by LT1GMC View Post
    The spin test will definitely indicate a totally blown clutch, but may not a slightly slipping one. The best indicator is to have a boost gauge, which is also helpful to trouble shoot other issues like boost leaks in the piping. You may want to check the BOV also.
    The clutch is not quite like most people would picture, it is actually a set of roller bearings set in an angled cage which kinda is like a ratchet, spins one way easy but friction locks the other. As these bearings wear, they begin to not hold as well, then will finally self destruct as the wear accelerates from increased slipping. Yamaha has improved/changed the design a few times over the years and they are definitely better, but still suffer when abused. (Abuse meaning higher than stock boost levels, higher rpm's, and compressor surging from rapid throttle releasing at high boost without a relief for the air already moving at a high rate stalling in the supercharger and pushing back on the turbine, stressing the clutch).
    So sounds like the clutch might be ok for now. (just felt weird when it clicked into locked position) I do ride it flat out most of the time, i try not to abuse it but can't be helped sometimes
    I will get a boost gauge for it and once i get it back together ill hook it up to see where its at.

    Thanks

  8. #8
    Just an update,
    Installed boost gauge, took it out and it read 10ish psi for 60 seconds then the clutch let go.

  9. #9
    That sucks, went through the same issue but it was from going to a 17 pound wheel that adds more stress. After 2 stock clutch bought Deans. Dean will stand behind the clutch. It can also be rebuilt but so far I haven't heard anyone needing to.

  10. #10
    Rook87's Avatar
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    My clutch has been replaced twice under warranty, worth a shot to keep you riding while saving for a dean clutch

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