Cranbrook, Chain shake/flap/slap

Discussion in 'Motorized Bicycle General Discussion' started by stilldoc, Oct 17, 2009.

  1. stilldoc

    stilldoc New Member

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    This is a new build and I am breaking in the engine. As you can see from the photo, I'm using the standard stock tensioner. There is little play in the chain which is a #41 that replaced the stock 415.

    http://i4.photobucket.com/albums/y109/stilldoc/photo-11.jpg

    Everything seems to be in line. There is very little wobble of the sprocket and it seems well centered.

    Despite that, the chain shakes violently, especially at low rpm's.
    I've had no problems with it coming off the sprocket.

    I guess this is a newbie "Is this normal?" post.

    Thanks for your help. I could post a video if needed.
     
  2. bandito

    bandito New Member

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    "Everything seems to be in line. There is very little wobble of the sprocket and it seems well centered."
    That sprocket needs to be centered PERFECTLY and parallel to the wheel. Its been my experience that one half inch of play up or down is all the play that is necessary on a chain. This doesnt apply to chains with spring loaded tensioners such as derailleurs. If your chain sprocket is off center by just 1/16th of an inch then the wobble will be an 1/8th when doubled by being round. The importance of having the chain parallel is to reduce wear on the sprocket and chain and to keep the chain from guiding off of the sprocket.
     
    #2 bandito, Oct 18, 2009
    Last edited: Oct 18, 2009
  3. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I would use the tightness of the rag jouint bolts to align the sprocket as carefully side-to-side as you can. I have had more problems with the sprocket being off-center, which causes the chain to tighten/loosen/tighten/loosen, and that causes a lot of noise and some vibration. I did run one bike like that for a loooong time with no ill effects, but it's better to get them as close to perfect as possible without tearing your hair out.

    I tighten them about 3/4 of the way, then use a rubber mallet to get it close to centered, then carefully tighten the nuts, keeping the sprocket strait. You don't need to make the rag joint bolts super tight, just snug.
     
  4. stilldoc

    stilldoc New Member

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    Thank you for your comments and recommendations.

    I don't think I could get the sprocket any more centered. As you can see on the attached photo, it's installed around a ring on the hub that makes it hard to not get it centered accurately.

    The lateral wobble is very small and I wouldn't think it could cause vertical shaking of the chain. How can I change it when the sprocket is pressed up against bare spokes (no other way to do it on this bike)?

    The chain is quite tight. About a half inch of slack.

    I think my question is, how much shaking of the chain is to be expected when everything is properly installed? I'm just lifting the wheel up off the pavement and allowing the wheel to turn at about 10 mph.
     

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  5. bandito

    bandito New Member

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    Ive installed alot of sprockets, pulleys and chains over the years but never a rag joint like these kits have on spokes......Bikeguyjoe could it be the chain he replaced not fitting on the sprocket correctly ie. spacing, width?
     
  6. xlite

    xlite New Member

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    Sprocket against spokes... baaaaaaad!
     
  7. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Don't use the center hole as a guide for centering the sprocket!!! Spin the wheel & use the tips of teeth for centering!!!
     
  8. freewheeling frank

    freewheeling frank New Member

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    the dropouts on the cranbrook are facing forward, i dont use a tensioner on mine. but the torque pulls the axle forward lossening the chain i plan on building some adjusters like on a motor cycle when i get time till then i carry a wrench in my back pocket and tighten it up as needed.
     
  9. BarelyAWake

    BarelyAWake New Member

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    The lawyer sez to remind you, the sprocket's teeth - not yers :p




    wow, that hurt just thinkin' about it lol
     
  10. bairdco

    bairdco a guy who makes cool bikes

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    get some of these.

    Wald rear hub washer. Serrated, 3/8in. | BikepartsUSA
     

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  11. xlite

    xlite New Member

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    I doubt that's what's happening. Out of dozens of bikes set up that way never saw an axel slip. It really can't happen if tightened properly. More likely the chain is wearing.
     
  12. pedal pusher

    pedal pusher Member

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    I just completed my first build and I am having the exact problems as StillDoc. My bike is Santa Fe, same as Cranbrook, just earlier version. I have the sprocket and adapter from Creative Engineering. I believe my trouble is with the tensioner as I think it is feeding the chain onto the sprocket in a slight twist with the inside of the chain being lower than the outside. I am going to try to remove the tensioner but fear the chain may hit the stay. If I roll my bike forward looking down onto the chain from above, I can see a little daylight between the sprocket and chain on the inside. If I roll it backward I can see a little daylight on the outside of the sprocket. Anyway, it definitely is not smooth. I had a 750cc Norton Altas with a worn drive gear and when I would get on it hard in first gear it would sometimes slip a little. The vibration and noise of my bike reminds me of that. Certainly not smooth, and I am about ready to either pull my remaining hair out, or shoot this thing.
    I believe whatever will help Doc will help me too.
    Thanks to all or I wouldn't have gotten it going in the first place.

    D. J.
     
  13. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    NOW THAT WAS FUNNY!!!! laff laff laff
     
  14. bandito

    bandito New Member

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    This chain problem is bugging me, if a chain is straight and the 2 sprockets are lined up straight and theres minimal amount of play in the chain there shouldnt be a problem. One other thing is the chain needs to fit the sprockets correctly in width and spacing. Some thing is outta whack here, either the motors not at 180deg or the chain doesnt fit or its not aligned properly. 1st problem post says the sprocket is almost centered then the second problem post says theres a twisting motion to the chain. rrrrrrg chains to run smoothly and worry free are installed correctly no short cuts.
     
    #14 bandito, Oct 20, 2009
    Last edited: Oct 20, 2009
  15. 2door

    2door Moderator
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    The tensioner wheel MUST be aligned with the chain path. In most cases this requires a slight twist to the tensioner bracket. Clamp it in a vise and using either a large adjustable wrench, vice grips or whatever you can grip the bracket with, twist it so the centerline of the tensioner wheel is perfectly parallel with the chain. The chainstays on most bicycles are not parallel with the rear wheel or the drive chain. When the kit tensioner bracket is clamped to it, the tensioner wheel aligns with the chainstay (frame) and not the chain. That's where the needed twist comes in.
    I just gotta do a picture tutorial on this some day.
    Tom
     
  16. marts1

    marts1 New Member

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    I don't get why the sprocket is pressed up against the spokes? Are you sure this is installed correctly?
     
  17. bandito

    bandito New Member

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    OK you guys have me thinking about these chains. On this site theres about 20 bikes to look at fully assembled...... SANTA CRUZ GREEN MOTORS-COMPLETE ASSEMBLED MOTORIZED BICYCLE-LINKS ....Im going to assume whoever is doing the assembling knows what theyre doing. On some of the bikes the chain looks nice and tight and on others the chain looks like it has 3 inches of play in it. Why do the ones that are loose have so much play? Is it necessary? I could see on a full suspension bike but not these because there might be a need for it. Length cant be the issue because some are loose and others nice and tight.
     
    #17 bandito, Oct 21, 2009
    Last edited: Oct 21, 2009
  18. BarelyAWake

    BarelyAWake New Member

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    Prolly cause the el'cheapo chains that come with these kits stretch so much and so quickly that they couldn't keep up with tensioning it...

    Or, the problem I have with my new 41 chain - I need it to stretch just a hair more so I can pull another link. Technically I suppose it'd be two links lol, I'd use a 1/2 link to get it just right but the only ones I've found use a lil cotter pin instead of a peened over head - with the 41 chain on my bike, I haven't the clearance to trust a cotter pin.

    I'm not sure I'd trust a cotter pin on my drive chain anyway o_O

    So I'm in the unenviable position where if I pull the link I've not enough, leave it and I've too much... blarg... Should be ready this weekend though :D
     
  19. xlite

    xlite New Member

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    All half links use a cotter pin. It's very reliable and the only way to do w/o a tensioner on some bikes. Fortunately my bikes have good dropout length and don't require it but several of the people I did bikes for weren't so lucky and need the half link. None have failed.


    Can't say that for the tensioners themselves.
     
  20. BarelyAWake

    BarelyAWake New Member

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    Yeah - I can see that, but sadly I still don't have the clearance for even a lil tiny cotter pin lol It'd clip the chainstay and/or kickstand mount (rear mounted) - my master link just clears (even under any side to side play), that cotter pin could just touch... bad news I bet. Heh - my build is a very tight squeeze ;)
     

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