Removing pedals off motorised bike and adding pull start

Discussion in 'Motorized Bicycle General Discussion' started by Lachiepower0402, Aug 31, 2014.

  1. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    I have received the pull start that I ordered. I have attached photos of parts that came with it, could someone please give me instructions of how to install it as it did not come with instructions.

    Thank you in advance,
    Lachiepower0402
     

    Attached Files:

  2. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    Another question, does this pull start work without any other modifications to the engine i.e. centrifugal clutch?

    Thank you in advance,
    Lachiepower0402
     
  3. Theon

    Theon New Member

    Joined:
    Jan 20, 2014
    Messages:
    1,440
    Likes Received:
    0
    The first bit goes between magnet and nut.
    second bit replaces mag cover.
     
  4. Davezilla

    Davezilla New Member

    Joined:
    Mar 15, 2014
    Messages:
    2,708
    Likes Received:
    2
    That's about all there is to installing a pull start, but you might need a slightly longer bolt to mount the pawlonto the crank over the mag coil as it usually don't come with a bolt and the one on your engine will only grab on by a few threads. You may also need to use a really thin washer or no washer under the head since there's very little clearance, basically, if it feels like it's binding on something or won't bolt all the way down it may be the crank bolt head interfearing with the pull assembly.

    Another thing to look at is if you notice more engine vibration after it's installed you may need to take off the aluminum adapter from the crank and turn it 180 and then reassemble since these parts aren't exactly perfectly balanced.

    Pedal clearance can be an issue too if you decide to keep your pedals or reinstall them.
     
  5. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    How tight do I do up the magnet bolt in nm?
     
  6. Davezilla

    Davezilla New Member

    Joined:
    Mar 15, 2014
    Messages:
    2,708
    Likes Received:
    2
    I'll need to convert it but if I remember right it's a fine threaded 8mm bolt so about 40 to 60 in/lb should do, this nut is fairly thin compared to what it should have there so getting a wider nut from the hardware store will help ensure it doesn't strip out. Mine stripped out but that was from using a cordless drill to crank over the engine and run a compression check after I built it. Using a wider nut with more thread contact fixed that problem too. :)

    For the factory nut tho, since there's really not enough threads left on the shaft to use a lock washer, use a few drops of Green (low strength) locktite on the threads or use blue if you can't get the green, just don't use red.

    I got a fine threaded nut (M8x1.0) from an auto parts store which is about twice as wide and can withstand normal torque much better than the one that's on there now.

    Basically go 30 to 40 in/lb and low strength locktite if using the factory nut, or go 40 to 60 in/lb and medium strength locktite if you get a regular thickness nut from a hardware store or auto parts place like pep boys or autozone.

    Some thread lockers (locktite) from other companies use purple for low strength and some are green... just another tidbit of gee-whiz info if you see the purple stuff and can't find the green...
     
  7. Theon

    Theon New Member

    Joined:
    Jan 20, 2014
    Messages:
    1,440
    Likes Received:
    0
    You may find the heads of the screws holding the mag in place will rub, removing washers will help.
    I had to do a little clearancing to the pawl also. you may be able to use a thicker washer between mag and pawl but that will limit the available thread.
     
  8. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    Hi again,

    So I tried to install the pull start on my bike and the threads lengths for the cover is not a problem.

    But the problem is that I cannot the remove the bolt holding the magnet, so I can put the pull start cup on, I have tried putting a screw driver in the flat head screw where the two gears are on the other side of the bike and trying to turn the magnet bolt, but it is way to tight.

    Has anyone got any suggestions on how to remove the bolt holding the magnet in, so I can install the pull start cup?

    Thank you in advance.
     
    #48 Lachiepower0402, Nov 21, 2014
    Last edited: Nov 21, 2014
  9. crassius

    crassius Well-Known Member

    Joined:
    Sep 30, 2012
    Messages:
    3,511
    Likes Received:
    48
    I usually put a 4.5mm allen wrench in the chain near the sprocket to hold the motor when working - a hand impact driver is sometimes needed for these too
     
  10. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    So what your saying is to, put a allen wrench in-between the top and bottom of the chain near the sprocket on the engine?
     
  11. irishpowerjunkie

    Joined:
    Jan 24, 2012
    Messages:
    115
    Likes Received:
    0
    lachie a safer and more proven method works for every petrol engine in known existence, remove spark plug, make sure piston is not in top dead centre( i use a small chainsaw file and turn engine by back wheel on mine) and when file has levelled out, no movement down pull it out and thread in rope into cylinder and loosen, same for tightening, and then move engine slightly to loosen pressure on rope and pull out, plug back in and your done.
    hope u can follow what i meant.
     
  12. Davezilla

    Davezilla New Member

    Joined:
    Mar 15, 2014
    Messages:
    2,708
    Likes Received:
    2
    I never thought about stuffing the cylinder with rope, but it would work...
    I usually just use a wide flat tip screwdriver in between the bevel and clutch gear to lock the crank if a bolt or nut is too tight to break loose and my 18 volt impact driver isn't handy... Usualy the impact wrench will do the trick every time without locking the crank. You can usually break loose the nut by putting a wrench on the nut and hitting it sharply with a small hammer if an impact wrench isn't available....
    There is a big "If ya know what you're doing" disclaimer for this one...
     
  13. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    I did that sort of thing for a lawn mower I was fixing to remove the flywheel bolt. I will have to wait until the next time I can work on my bike as it is at one of my friends places. Thanks for the idea!
     
  14. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    So I stuffed the cylinder with rope and was able to remove the bolt holding the magnet in place. But as mentioned before their is no enough threads for the bolt to grab onto, which means I will have to get a longer bolt which the magnet mounts onto.

    Is this 'easy' to replace and where can I get the part?

    Thank you in advance
     
  15. Davezilla

    Davezilla New Member

    Joined:
    Mar 15, 2014
    Messages:
    2,708
    Likes Received:
    2
    If you're talking about the bolt, replacing it is easy, just take the old one to a hardware store and match up the thread size, they're cheap and usually of much better quality than what came with the engine.

    For the magnet, lots of people sell parts online like Dax, Gasbike, Jake's, Pistonbike, and many others including ebay.

    When it comes to hardware, I always replace anything I take out with the good stuff like grade 8.8 or 10.9, just cheap insurance there.
     
  16. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    So the bolt is just a normal threaded rod, not the whole crankshaft? Also how do I remove the bolt.

    I just want to replace the rod, not the magnet.

    Thank you in advance
     
  17. Davezilla

    Davezilla New Member

    Joined:
    Mar 15, 2014
    Messages:
    2,708
    Likes Received:
    2
    The bolt is the end of the cranshaft that's threaded, then the magnet goes on and a nut holds it all down... What you'll want is a new nut that isn't so cheesy and thin that it can strip easily ruining the threads on the crank. I just got a wider M10 nut to replace the stock nut with since mine did strip after a few drill starts, there's not much to do to fix the damaged threads, but the wider nut grabs more of the threads that are intact than the stock nut, the stock nut only grabs 3 threads making it very vulnerable, but a regular width nut will have about 8 threads so it can still grab 5 threads if the crank did strip, which is still 2 more threads than stock. you may need to ditch any washers there and use blue locktite to get enough thread engagement if it did strip, but it'll still be better than stock.
     
  18. Lachiepower0402

    Joined:
    Mar 5, 2014
    Messages:
    114
    Likes Received:
    0
    So after I remove the bolt and magnet the threaded bolt should just screw out of the crankshaft?

    Then I should buy a new and better quality nut and threaded bolt?

    Thank you in advance
     
  19. Davezilla

    Davezilla New Member

    Joined:
    Mar 15, 2014
    Messages:
    2,708
    Likes Received:
    2
    Not exactly, that end of the crank has threads cut on it, there's only a nut on the magnet side... Here's a pic of my other engine with the new nut on it, this nut is almost triple the width of the original and will not strip out or ruin the threads on the crank... The nut size you'll need if this is the one is M10x 1.0 if I remember right, but always best to take the nut (or the engine) with you if not sure, or if you have a thread gauge you can find out the right size that way.

    [​IMG]

    Here's a pic of the engine stand I made for doing desktop or benchtop repairs, it balances well for display too, but C clamps to the edge of a table, bench, or desk if any torque is needed, it can also run this way with an aux tank or an iv stand or whatever and a pull start installed.
    Just putting this here for inquiring minds... and to show a Real easy way to work your engine off the bike.
    [​IMG]
     
    #59 Davezilla, Dec 29, 2014
    Last edited: Dec 29, 2014
  20. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,495
    Likes Received:
    50
    Purty cool stand, Davezilla. Form an' function.
     

Share This Page