First build problems

Discussion in '2-Stroke Engines' started by Bushman, Jul 11, 2010.

  1. Bushman

    Bushman New Member

    I am working on a couple of bikes and have got the first one together and running but have a couple of questions. I am using the Grubee 66cc from a kit on a Nirve bike.

    1. I get some grinding type noise near the drive sprocket when I have the clutch in and roll the bike. If I roll it slow you can feel and see the chain jump slightly near the drive sprocket. I have the 410 chain.

    2. It starts a little hard and seems like it is being restricted and wants to go faster. I have a NSK B6HS plug gapped at .024 and a new plug wire. Maybe the carb needs adjusting?

    3. What would be the best way to hook up a kill switch on an aluminum framed bike? Can I go to the motor mount?

    Thanks.
     

  2. Pablo

    Pablo Motored Bikes Sponsor

    1) Hard to say, probably chain alignment. Is your little ball well greased? Or maybe just the drive gears on the clutch side. Are they greased?

    2) For sure the carb will need adjusting - but you need to ride the pig to break it in before it runs smooth.

    3) Why would the frame alloy make a difference? Mount sounds fine.
     
  3. Stan4d

    Stan4d Banned

     
  4. Bushman

    Bushman New Member

    I did grease the ball but did not check the gears. I will check it out. I have only about an hour on it so your right I will have to ride it some more to break it in. Im not sure how to align the chain so I will search the forum. I measured from the center of the rear hub to the center of the chain and from the center of the frame to the chain at the motor and the are within .10 just by eyeballing it. I think it mat be something in the motor. I will check the gears in the clutch.
     
  5. Stan4d

    Stan4d Banned

  6. Bushman

    Bushman New Member

    Thanks for the link. Sounds familiar. I will check rear sprocket to make sure it spins true next.
     
  7. Bushman

    Bushman New Member

    Well I remounted the rag joint on the rear wheel getting it as true as I could. It ran pretty good but it seems with time it gets out of whack again. There is a bit of slack between the I.D of the rear sprocket and the O.D of the end of the wheel hub. So in time it gets knocked out of round again. I was going to make a spacer but the end of my hub has like a 10 degree taper on it. My chain gets tight in spots and lose in others - sprocket not true. Any suggestions?
     
  8. Stan4d

    Stan4d Banned

    Are you saying that the sprocket is oval? if so then it needs to be replaced.
    If you can get it true but is slips out of true, I would make sure you have the rubber spacers on both sides of the spokes and that you have the bolts tight enough to hold it, but they should all have the same tightness (torque for the picky ones).
     
  9. Bushman

    Bushman New Member

    The sprocket is not out of round. I just think it moves. I do have the rubber spacer on both sides of the spokes but maybe I don't have it tight enough.
     
  10. Stan4d

    Stan4d Banned

    Sounds like it.....I tightened mine just enough to "surround" the spokes with rubber. Not so tight as to change the shape of the wheel but not losse enough to have a space visible between the rubber spacers.
     
  11. Al.Fisherman

    Al.Fisherman Active Member

    When the rag joint is installed there is plenty of thread sticking out of the nut. The bolts they supply surprised me in the fact that they are a grade 8.8

    What I did was I went to where I buy my hardware, and got a bolt just long enough that only about three threads are exposed after the nut is installed. I buy the nylon self locking nuts by a box of 100. Remove one bolt at a time and replace all nine. The bolts can be cut to size but I use them when I included a bolt in the clutch rollers I make. Have not had to re tighten them in a year so far.
     
  12. Bushman

    Bushman New Member

    Yeah, I did the same thing. I got a box of 100. It turns out I am getting a new rear wheel from the manufacture. The original had a bad freewheel. When it arrives I will try my best to get the rag joint on straight this time.
    Whats the best way to check that the rear sprocket is turning true? I was planning on tipping the bike over and just spinning it on the bike. I want to try to get away from the chain tensioner so I am going to adjust the drive side first and then the pedal side because of the horizontal dropouts.
     
  13. Al.Fisherman

    Al.Fisherman Active Member

    Turn the bike over, spin wheel (front and rear) look for wobble. Tune by adjusting spokes (always tighten, don't loosen) Install rag joint then secure axle in the vertical position, spin wheel, if sprocket needs adjustment hang a plumb above and adjust, turning the wheel..while the axle remains stationary.
     
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