chain alignment

Discussion in 'General Questions' started by japat100, Jul 16, 2007.

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  1. japat100

    japat100 Guest

    i think some of us take for granted once we put the motor in place the chain will line up with the back sprocket ,,and then we start blaming the tension bracket because the chain is not running smooth ,,,i put a laser on mine and found it was out over 1 inch ,,now i have to make a off- set bracket on the back mount to line the chain up ,, in order for the chain to run smooth these sprockets must be line up and also very important they must be plume to each other ,,i am beginning to think setting up these motors properly is not a job for a mechanic but a job for a magician
    if mine is out over a inch then i can not figure out if you have the same motor,, how yours could be true because they would have come from the same molds and i am sure your back sprocket is not mounted in the middle of your back wheel

    i am only a half a mechanic and not a magician now i 'm in trouble

  2. azvinnie

    azvinnie Guest

    post some pics so people have a better understanding, and this way we can try to help you better, thanx
  3. japat100

    japat100 Guest

    thanks for reply ,, if you take chain cover off and chain off place a straight edge between the small sprocket and the back one the straight edge ends up about 1 inch inside the back sprocket ,,, the only way i see to correct this i would have to give my motor a quarter in. turn clockwise and since the mounts and the bolts on the mounts are a snug fit it is impossible ,, so the only answer i see is to make a off-set bracket on the back mount ,,and what really puzzle me if mine is not true ,then if you have this 70cc motor from eBay then how could any of them be true ,because these are preset mounts ,,and if this is the case then it is no wonder there is so much talk about getting the tension bracket right ,,in other words its not the tension bracket thats the problem its the alignment of the chain ,, interesting to hear from other members that are running 70cc
  4. gone_fishin

    gone_fishin Guest

    on my frame, alignment was almost automatic...we need pics of your application to see what you're talking about.
  5. Dockspa1

    Dockspa1 Guest

    My problem is after getting the chain aligned the bottom frame bar still rubs the chain and no matter how I raise the idler, it still rubs. I tried putting a spacer in between the drop out and axel but it still rubs. If I pull the chain out of alignment with the idler, it won't rub but the chain is then out of alignment.
    Dear ABBEY, what next?
  6. On my Specialized Rock Hopper I had to clamp the tensioner to the stay and use a large pipe wrench to modify the bracket so the idler wheel was centered with the chain.....I am not sure just how far out my alignment is but I do know the bracket did need a little tweaking....I haven't had a a thrown chain yet or any unusual wear.

  7. turbo/chaos

    turbo/chaos Guest

    whats strange i have had to work on 3 spelized frams now and each
    one i have had to wrap cardboard arond the spot where i am placeing the tensinor

    and then tapeing it tight with electric tape and you might have to
    bend back the tensinor with a stupid wrench and on those frams
    wont budge a inch at all beacasue the frame is box shaped in a way
    but in a rectanguler way (still cant spell right AHHHHH!)

    hope it helps you TURBO CHAOS
  8. Dockspa1

    Dockspa1 Guest

    Thanks Andrew and Turbo. I will give it a try.
  9. Scottm

    Scottm Guest

    How did this work out? My chain is rubbing the tire just barely. I've twisted my tensioner with pliers but may have to tilt it back a hair to keep the bottom chain from rubbing.
  10. Dockspa1

    Dockspa1 Guest

    I bent the tensioner and the tentioner is running straight with the chain but it still wants to pull the tensioner to one side so I know the chain alignment is out.
    Will try to put more spacers in the back to see if the straight edge lines up.
    Last edited by a moderator: Nov 1, 2007
  11. alesterfeind

    alesterfeind Guest

    On my old bike, the tensioner would pull in toward the tire and forward toward the seat post causing the chain to loosen and misalign. I used self tapping screws through the tensioner bracket right into the frame. Worked like a charm.
  12. Dockspa1

    Dockspa1 Guest

    This on an old sears 3 speed. I already put a single speed hub on it for ridgitity.
    It's in bad enough condition that I might just use your idea Johnny. I thought about welding it but then sometime down the road you will have to remove it.
    Thanks again
  13. Scottm

    Scottm Guest

    chain deflection and tension

    The chain on my jaguar is rubbing the tire (as mentioned before). If you look closely you can see the pattern on the tire where the link pins hit. I pulled the derailuers off an bike in the junk yard. Turned it upside down and it mounted to the frame perfectly! I was wondering if the roller could/should (not) be used:?:. I am just trying to deflect the chain a hair to keep it off the tire. The front derailuer can not go down any further but can come up. The pictures lie a little since right now there is slack in the chain, but I will adjust the bottom tensioner properly.

    If I have hi jacked your thread please let me know. I just didn't want to start a new one.

    Attached Files:

    Last edited by a moderator: Nov 9, 2007
  14. japat100

    japat100 Guest

    you should be able to move the motor over just a bit to clear ,,i had to file the back mount on the chain side and then add a spacer on the other side of the mount ,,worth a look . i think i might have gain .3 inches just enough to clear

    it"s not easy to keep the derailed sprocket in place on the top as you have in the pic ,, there is as you know a lot of tension on the top ,,
    good luck
  15. Dockspa1

    Dockspa1 Guest

    Scott, the drailer metal is not made for the torque you are applying on it. For your safety, I would go to something a little more durable. Could be an accident waiting to happen. I could be wrong Scott but, I can bend the derailer by hand.
  16. azbill

    azbill Active Member

    yes, the top should have no tension on it
    it should only be guided if anything
    i am afraid the first hard ride it will self-destruct and do damage
    is it posible to dish your sprocket out?
    (that is, if you haven't got it that way already)
  17. Scottm

    Scottm Guest

    Better my peers tell me "no" now than my bike tell me "no" later.Hmmmm
    Japat, I welded the front mount since the frame is so strange with no thought to the chain vs tire issue. On Mr. Toad, the chain just nibbled off the nobs that stuck out too far Fiddlesticks!
    Doc you are right the metal is softer than modeling clay. I did bend the front parts out so that the chain would not catch on it's way through. I had to bend/widen the whole thing just so the chain would fit in. I reckon it will be rather noisey, and the chain will rub through the metal rather quickly, could cause a snag jerking the derailuer around the post while binding up the chain. Scary thought. The wheel was just a thought. Kind of looks like a cowboy's spur, Just like Roy and Gene huh Doc?

    Guess the easiest thing to do is just have a new slimmer tire put on. I need to learn how to do that anyhow plus I'll have a spare for the front.

    I asked because I trust you all and Alesterfeind suggested a second opinion.
  18. Dockspa1

    Dockspa1 Guest

    Ah! my grasshopper, A wise man once told me " it is safer to lose pride than face".
    Believe me Scott, we wouldn't say anything if we didn't care! "About duke! He has to ride with you!!!
    Ha Ha
  19. Scottm

    Scottm Guest

    Okay another perhaps safer and sound train of thought suggested by Alesterfeind. What if I put some spacers/washers between the rear sprocket and the rubber spacer, that should give me more clearance BUT the chain will be at a slight angle. Like Japat said just .3 inches. Doable?

    It will be 86 degrees here today and the kids are at grandma and grandpa's so I might be out most of the day on Mr. Toad. The front wheel of my new project is at the bike shop having a disk brake installed and I'm still wiating for my replacemnet fork.
    Have a great day.
    Last edited by a moderator: Nov 10, 2007
  20. Alaskavan

    Alaskavan Guest