Pedal? , crank? problem

Discussion in 'Bicycle Repair' started by LaMorte, Jul 31, 2008.

  1. LaMorte

    LaMorte New Member

    Hi,
    I have a cruiser, chain brake, motorized bike. Lately when I begin to pedal with some oomph to get started the pedals slip and move forward about 1/8 revolution, catch a little then slip again. There is nothing wrong with the actual pedals that the feet go on, rather the action of pedaling.

    Here is a photo of the bike so you can see what I have.

    Sorry if this question is also in another forum, I tried searching for my issue a few times, but not luck.

    Thanks for any suggestions.:shock:
     

  2. pedalpower

    pedalpower Member

    chain slip?

    sounds like either the chain is slipping out of the front "chainwheel" or slipping out of the rear cog. Is this an internal 3-speed that could be failing?

    It could be a cheap chain or the chain is not tight enough or the wrong sized chain for the size of the sprockets. I see the bike has horizontal dropouts so make sure everything is tight (both chains).
     
  3. Pablo

    Pablo Motored Bikes Sponsor

    So this is when you are starting the engine? Sounds like the clutch is slipping.

    Or just pedaling with the clutch in?
     
  4. LaMorte

    LaMorte New Member

    Well it happens when I am trying to start the engine and just when I am using the bike without the clutch engaged. Today it was really slipping much more, almost 1/2 revolution while I try to pedal. At times it was hard to get the bike to move, and when I engaged the clutch, I couldn't get enough power in the pedaling to even get it to turn over. I hope I am explaining this well-- when I pedal with force it feels like the "pedal" just slides forward and doesn't engage the chain. It is a one speed bike and all the chains seem taught they way they should.
     
  5. pedalpower

    pedalpower Member

    sorry, but if the chain is not slipping over the tops of the teeth then it sounds like your freehub or single speed cassette is fried (read rachete mechanism). beauty of a build btw.
     
  6. does it feel like it's slipping int eh bottom bracket, where your peddles meet the frame? Could there be an issue with your bearings?
     
  7. LaMorte

    LaMorte New Member

    yeah the bottom bracket is exactly where it feels to be slipping-- I bet I should take off the pedal thing-- can you tell I'm not a gear head? I really appreciate everybody's thoughts on this.

    THanks so much!
     
  8. pedalpower

    pedalpower Member

    okay, that doesn't make any any sense to me. All the bottom bracket does is slip. if you remove the chain, the pedals and crank should just spin.

    I want you to check something for me. how far into the front sprocket does the chain sit? are the teeth centered between each link?

    I need to know more about the rear sprocket and the same questions apply to the rear.

    you may think the chain is tight enough but it's too loose if the your getting tooth skipping.


    Okay, I just thought about this. How is the front sprocket connected to the crank (1 piece?) is the sprocket in a knotch on the crank? is there a nut that tightens the sprocket against the crank?
     
  9. BB

    To get the crank out of the bottom bracket you'll need a special tool...

    search ebay and you'll find lots of them.. (Bottom bracket tool)

    a warning- if you don't like grease, you won't like doing this repair... If your bearings are shot- your gonna have greasy ball bearings falling all over the place.
     
  10. HoughMade

    HoughMade Guest

    Take apart your coaster break hub and check for damage. Sounds like you need a rebuild- the proble in not in the bottom bracket.
     
  11. ocscully

    ocscully Member

    Stiff Chain Link?

    http://bicycletutor.com/stiff-chain-link/ Here is a link to a video about Stiff Chain Links. A stiff link could be the cause of your skipping problem. It will be harder to find the link in your chain since you can't back pedal a coaster brake, but if there is a link stiff enough to cause the slipping you describe you should be able to see it even pedaling forward.

    ocscully
     
  12. duivendyk

    duivendyk Guest

    I think the one way roller clutch in the rear hub is malfunctioning,that is it does not engage properly,the rollers are prob. sticking and not riding up the ramps as they should.The hub needs to be taken apart and cleaned,regreased or repaired.
     
  13. 1968gtcs

    1968gtcs New Member

    Your problem is your freewheel cassete/cog on your rear wheel. These walmart/target bikes have cheap China parts that aren't meant to last, especially at the speed of an engine. It depends, but if the freewheel isn't removable(built into the hub) as I suspect, you will have to get a new wheel and put a nice feewheel on it. It isn't worth your time to take it apart and mess with it, just buy another wheel and put an ACS Claws freewheel. These you can get for less than $20 and will last a long time with an engine. Don't get the cheap Shimano or China ones, or you will have your problem all over again. If you have to get a new wheel, get one with a disc brake hub so you can mount a sprocket to the hub instead of against the spokes.
     
    Last edited: Aug 2, 2008
  14. HoughMade

    HoughMade Guest

    Coaster brake- no freewheel cassette.
     
  15. pedalpower

    pedalpower Member

    okay, I have not yet seen a motorized fixed gear yet (untilI build one). I agree that the problem in the rear hub. Keep the single speed set up. but I think the freehub or fee cassette and rim brakes are more reliable in my opinion. your LBS should be able to help you build a new wheel or repair the hub.
     
  16. duivendyk

    duivendyk Guest

    Coaster brakes are inadequate for the higher speeds you now run at with your engine.They get too hot,the grease melts away and things begin to stick inside.Get a freewheel disk brake hub or rim brakes.I see no sign of any other brake either,you need a front brake too,a drum brake would be easiest to install.Try not to become a statistic.
     
    Last edited by a moderator: Aug 2, 2008
  17. 1968gtcs

    1968gtcs New Member

    I agree.......you need a good front and rear brakes. The most important thing on your bike is being able to stop.
     
  18. HERPER

    HERPER Member

    i had the same thing, it ended up being my coaster brakes ripping to shreds on the inside.
     
  19. HoughMade

    HoughMade Guest

    Coaster brakes can be used if:

    a) they are not your only brake (no brake should be your only brake), and

    b) you repack them with automotive high-temp wheel bearing grease.
     
  20. LaMorte

    LaMorte New Member

    Thanks for the feedback everybody. I am going to have the person who did the build take a look at it for me and pass along your thoughts on the issue. I did have front and rear brakes put on a few weeks ago, but that was after the photo was taken. Yay for lots of brakes.

    Thank you again everybody, you have really helped me a lot with this.
     
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