Bummer, mechanical failure at 11, 800 feet AGL

Discussion in '2-Stroke Engines' started by Skyliner70cc, Aug 22, 2010.

  1. Skyliner70cc

    Skyliner70cc Active Member

    On my way home from my camping trip I decided to ride my HT powered shifter bike up Cottonwood Pass 12,126 feet in altitude. It was a beautiful day and very warm. Traffic was pretty heavy and I was lucky not to get run over.

    All was going well until about 13 miles into the journey from Taylor Park Reservoir. About 1/2 mile from the summit of the pass my ^Y&*(&^%^&*ING heavy duty freewheel hub failed!!!!!!! I couldn't even pedal the final 1/2 mile to the summit. I figured I was at about 11,800 ft AGL when this failure occurred.

    As for my HT engine, it ran beautifully and had no problem reaching speeds that exceeded my comfort level on the dirt road on the western side of the pass. Fuel was regular unleaded running 100% castor at a 32:1 ratio. BGF HT engine on a SBP tuned pipe and shifter kit. 9 tooth right sprocket on shifter kit and 36 tooth mega gear 1st gear. Needs more pull at lower speeds, was adequate for Cottonwood pass but not enough to go slow over other rough "roads" that I road on during my camping trip.
     
    Last edited: Aug 22, 2010

  2. GearNut

    GearNut Active Member

    I am sorry to hear that! At least you were on your way home instead of just starting out.
     
  3. Skyliner70cc

    Skyliner70cc Active Member

    I was just bummed out because I wanted to be able to go over 12k agl in a HT engine. Next summer, I'm going to see If I can go to 14k.

    I can't complain, I did do some awesome trail riding on my HT motorized bike. The HT did great on those 10% grades, too bad the freewheel didn't hold up.
     
  4. AussieSteve

    AussieSteve Active Member

    Out of interest, what failed on the HD freewheel - pawls or bearing?
     
  5. Skyliner70cc

    Skyliner70cc Active Member

    Aussie,
    I'm guessing pawls because nothing is driven when I pedal.
     
  6. RdKryton

    RdKryton Active Member

    Skyliner70cc.
    I had to laugh when I read the title. I thought to myself, 11,800 AGL above ground level? Wow that thing really fly's. I know you meant above sea level but I just had to giggle at first. Sorry you had a failure especially in a wonderful place like that. Hope you can get it straightened out without it costing an arm and a leg.

    Jim
     
    Last edited: Aug 27, 2010
  7. Skyliner70cc

    Skyliner70cc Active Member

    Sorry, got AGL and SL mixed up.....former military pilot who hasn't flown in a long time ;-)
     
  8. RdKryton

    RdKryton Active Member

    No problem. I thought it was a funny little senior moment. I have them all the time...

    Jim
     
  9. Fabian

    Fabian Well-Known Member

    You will find that pawls have not failed (they are bullet proof), but it's the 67082RS bearing that will have failed:


    158540317_enduro-bearings-6708-2rs-6w-bearing.jpg


    and when the bearing completely fails, the inner and outer shells separate from each other, which in turn chews out the blue locking ring; allowing the jackshaft sprockets attached to the outer section of the Heavy Duty freewheel bearing to move outwards, thereby detaching itself from the pawl mechanism.

    Although the White Industries Heavy Duty Freewheel bearing is a far superior design in material construction and durability than the basic freewheel bearings on the market, the weak link in the system is the 67082RS bearing.
    From my experience, and as part of regular maintenance, you "MUST" be vigilant in inspecting the bearing slop, by grabbing the 44 tooth sprocket and giving it a wiggle. The bearing should be changed when slop gets to about 1/8 of an inch.

    So long as you replace the bearing when it starts to give out, you won't have any problems with it failing on a ride.
    If the bearing does suffer a complete failure, you "MUST" replace not only the bearing but also the blue locking ring and the snap ring, regardless if they look ok.

    SickBikeParts sells these components individually, but you have to ask for them by name.
     
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