My third wreck due to "issues" with bike

Discussion in 'Motorized Bicycle General Discussion' started by sentnl, Nov 26, 2014.

  1. SuperDave

    SuperDave New Member

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    I think what is meant to put the tensioner on the pedal side is to shorten the drive chain to the shortest you can get away with, adjust the wheel to fit it just right, then use the tensioner on the pedal chain to take up any slack. If your dropouts are rearward open(axle slides in from behind), I'd recommend banjo bolts to center & lock in the axle. My Skyhawk GT2 frame is set up like that & I use banjo bolts on mine. If the dropouts are forwards open(axle slides in from below diagonally), you might try grinding a flat spot on the backside for the banjos to hold, but that may weaken the structural integrity that could lead to breakage on a pothole or hopping off a curb, leading yet to another crash, not to mention the death of the frame.

    I've had the nut on the magneto come loose and back off, it dented the mag cover & litterally locked up my motor. I thought it seized on me. Lucky I was only riding slow at the time, at full throttle it may have busted the cover open or lock up the back tire at speed. This was before I used locktite blue on everything.
     
  2. Greg58

    Greg58 Well-Known Member

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    Hey Dave did you ever rebuild the engine that burned the hole in the piston?( Sorry for interrupting the thread but I saw Dave's post and remembered his blown engine.)
     
  3. SuperDave

    SuperDave New Member

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    Yeah, but it didn't last 3 tanks of gas. The wrist pin bearing cage gave loose and dropped a few needles into the crankcase. I lucked out when it happened, was cruising slow when I heard/felt the piston tapping the head so I shut it down immediately & peddled home. It never sucked anything past the transfers so my top end survived with only light witness marks on the piston crown where it kissed the squish ring. I think I can sand & polish them out.

    Bike has been on the back burner all summer long with electrical gremlins plaguing it, I made the mistake of using solid core copper wires when I SHOULD have went with stranded. Solid wires don't like to live in an environment where they are subjected to lots of bending (such as handlebars) and now I have shorts in my lighting. So this winter I'm having to rip out nearly everything and start all over again.
     
  4. sentnl

    sentnl New Member

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    I have bought 2 bolts, both have been too long. I think I need a washer. the original slotted head is pretty wide and I guess rests on the gear instead of inside of it. Yea or nay?
     
  5. sentnl

    sentnl New Member

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    Man I wish some of you guys were closer. Move to the WEST SLOPE!!!! haha...
     
  6. crassius

    crassius Well-Known Member

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    yes, it must push the gear onto the shaft
     
  7. Greg58

    Greg58 Well-Known Member

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    That's why I posted the link to the correct bolt, it needs to be right.
     
  8. sentnl

    sentnl New Member

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    Yeah, I dont feel comfortable using the hex head bolt. I am going to endure the waiting process for the correct bolt. No offense, redneck, I just am a firm believer in OEM standards etc....
     
  9. redneck82

    redneck82 Member

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    none taken, no worries
     
  10. KCvale

    KCvale Well-Known Member

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    Glad you are OK and I like the quarter idea, maybe even a 1/2 dollar ;-}

    It sounds to me like the bolt came out seizing your motor first, and THEN your tensioner broke because of the sheer direct force of your back wheel trying to turn the chain. I can't see it going the other way.

    If you had a full head of steam that would be like a whack straight down on the tensioner wheel with a sledge hammer.

    Are you running #41 chain, or the stock #415?
    415 should have broke but I can see 41 not giving first.

    I have no problem with stock bearing tensioners and put them on most every build for customer tuning convenience, the trick is to get the chain as close to perfect first, and then mount the tensioner to leave the most adjustment up.


    Regardless of what you do with chain tension I suggest:

    Pull off your back wheel and check everything is still true and no damage, I can see the sprocket turning until it hit a spoke and who knows what else after that like it's alignment and even the wheel trueness.

    Check your motor drive sprocket, a jolt like that could have easily sheered the woodruff key.

    And most importantly check your engine mounts! I have seen similar abrupt engine sprocket stops that have ripped the engine almost all the way out of the frame and in another case actually breaking the frame.

    I have pics somewhere, anyway the simple rule of thumb is if you can move your engine AT ALL holding the top bar with one hand and the head with the other, pushing back and forth AS HARD AS YOU CAN, it is a fail.

    Best of luck on the rebuild and I hope that helped.
     

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