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Starter, Gears and One Way Clutch Inspection

Discussion in 'General Yamaha Discussion' started by grizztracks, Dec 6, 2017.

  1. grizztracks

    grizztracks Tech Advisor Tech Advisor VIP Member

    Messages:
    2,514
    Location:
    Scio, NY
    Country:
    USA
    Snowmobile:
    FX Nytro RTX, RS Vector, SR Viper RTX SE
    I have a low mileage 2005 RS Vector in the garage that came in with a starter issue and for a chain tensioner update.

    The starter was still capable of starting the engine but it acted as if it was kicking out or skipping teeth on the gears. The starter was removed and a bench test performed which indicated that the starter worked but sounded a little rough so a new one was ordered. To inspect the gears the stator cover was removed but no obvious failures could be seen so the flywheel was removed to inspect the one way starter clutch. The hub on the flywheel gear that the clutch bearing locks to during startup had noticeable wear which I suspect was causing the problem so a new idler gear, idler gear pin, one way clutch and flywheel gear was also ordered.

    When replacing any one of these starter component on the Yamaha 4-stroke engines I recommend that all the related parts are replaced. The good thing about replacing all the starer parts is that there have been updates to the gears to make them stronger.

    Stator cover removed to inspect starter gears (flywheel also removed):
    starter gear.jpg

    Starter flywheel gear with a bad one way clutch hub:
    IMG_5516.JPG

    New updated idler gear. Notice that there are no webs in the gear and the teeth that the start motor's small gear runs on are now wider:
    IMG_5514.JPG
    IMG_5512.JPG

    New updated one way clutch looks to be stronger than the old one:
    IMG_5507.JPG
    Old one way clutch installed on flywheel:
    IMG_5509.JPG

    New one way clutch installed on flywheel:
    IMG_5510.JPG

    I didn't notice any significant changes made to the large flywheel gear that locks to the one way clutch but I thought after all the Viper starter gear failures that Yamaha switched them all to chromoly for additional strength.
     
    Last edited: Dec 6, 2017
  2.  
  3. cannondale27

    cannondale27 Moderator Staff Member Moderator Vendor Lifetime VIP Member VIP Member

    Messages:
    14,627
    Location:
    Manitowoc,WI
    Grizz could you pop the old One-Way out of housing. It should come out just pretty easy. Just spring loaded. Also the gear you show is a very different gear than has been in Vipers/Vectors since 14. But the part # is a new number even in the newer sleds. Just identical looking to new gear you have pictured. So there have been at least 3 different gears used in this engine. Good advice on new everything. How Much do parts cost though?
    Here is both from a Viper. One on right failed.
    DD9D64DB-C3CD-4415-83A0-10A62C427CDB.jpeg
     
    Last edited: Dec 7, 2017
  4. grizztracks

    grizztracks Tech Advisor Tech Advisor VIP Member

    Messages:
    2,514
    Location:
    Scio, NY
    Country:
    USA
    Snowmobile:
    FX Nytro RTX, RS Vector, SR Viper RTX SE
    Yes, I can easily remove the one way roller cage from the mounting ring housing. Is there anything special you want me to look for there or did you want a picture of it apart? All the starter parts inside the stator cover ran about $275. Because the one way clutch caused wear on the hub of the large starter gear both the gear and clutch needed replaced so for an additional $60 it only made sense to update to the new idler gear.

    With the way it was starting I really thought I'd find a bad gear in there. After finding no damage to the gears and seeing how the one way wore the hub I'm now thinking that the start problem was caused by the one way clutch not locking properly. It looks like it might have been chattering on the hub and that's why it sounded like it was skipping during a startup.
     
  5. cannondale27

    cannondale27 Moderator Staff Member Moderator Vendor Lifetime VIP Member VIP Member

    Messages:
    14,627
    Location:
    Manitowoc,WI
    Yes a pic. Very familiar with these. If it has a small dia wound spring that’s usually source of issue. Any kinks in it the pawls will hang up on. Thank you! Never went in even that far on one.
     
  6. MrSled

    MrSled Administrator Staff Member Admin Moderator VIP Member

    Messages:
    16,277
    Location:
    Schofield, WI
    Country:
    USA
    Snowmobile:
    2017 Sidewinder
    We should add this info to the RS, Nytro and Viper FAQ. The Apex motors are very similar but the motor will have to be pulled or lifted to get the mag cover off.
     
    cannondale27 likes this.
  7. grizztracks

    grizztracks Tech Advisor Tech Advisor VIP Member

    Messages:
    2,514
    Location:
    Scio, NY
    Country:
    USA
    Snowmobile:
    FX Nytro RTX, RS Vector, SR Viper RTX SE
    As cannondale27 suggested I took a closer look at the one way clutch. Before disassembling it I noticed a few stretched areas and one kink in the spring that holds the locking rollers in place. With it apart there's definitely some noticeable issues but what caused the failure in a relatively low mileage engine when there are many out there with a lot more trouble free miles?

    IMG_5520.JPG IMG_5521.JPG
     
    cannondale27 likes this.
  8. cannondale27

    cannondale27 Moderator Staff Member Moderator Vendor Lifetime VIP Member VIP Member

    Messages:
    14,627
    Location:
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    Holy cow! Never saw one that bad! I agree something out of norm happened here. Maybe the hub it grabs was soft?
     
  9. cannondale27

    cannondale27 Moderator Staff Member Moderator Vendor Lifetime VIP Member VIP Member

    Messages:
    14,627
    Location:
    Manitowoc,WI
    I will add it if not done already when I get home.
     
  10. MrSled

    MrSled Administrator Staff Member Admin Moderator VIP Member

    Messages:
    16,277
    Location:
    Schofield, WI
    Country:
    USA
    Snowmobile:
    2017 Sidewinder
    Got it covered.
     
    maim and cannondale27 like this.
  11. cannondale27

    cannondale27 Moderator Staff Member Moderator Vendor Lifetime VIP Member VIP Member

    Messages:
    14,627
    Location:
    Manitowoc,WI
    Thanks MrSled!
     
    MrSled likes this.

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