Sprockets How do I get the 10 tooth Drive Sprocket off of the China Engine Kits?

Discussion in 'Transmission / Drivetrain' started by Bonefish, May 29, 2010.

  1. Bonefish

    Bonefish Member

    I removed the cover, took off the nut holding the sprocket on, and then took the washer off and see that it is a keyed sprocket. It does not come off though after I take off the nut. I tried to pry it up, but it wouldn't come up. What do I do to get it off?


  2. Al.Fisherman

    Al.Fisherman Active Member

    The double ended wheel puller is used to remove it. In the picture you will see it used on the clutch drive gear. Screw the large threaded end into the 10 tooth gear as tight as you can, take a wrench securing the tool itself and take a (I think) 14mm box wrench and tighten down. The gear should slide off. At times you may need to get gear puller (center shaft) as tight as you can and strike the hex head with a hammer, and tighten again. Repeat steps as necessary.

    Check out my photo album....photo 24 through 30


    Photo 24 of 59 Now to remove the engine drive gear. As you can see we used the chain to keep the gear from turning while removing the nut.

    Photo 25 of 59 To remove the nut holding the drive gear on, you can use the supplied socket wrench (opposite end of spark plug wrench). That wrench supplied is such a poor quality that I choose to use a 19mm 3/8 drive socket.

    Photo 26 of 59 As you can see I had to use a little friendly persuasion.

    Photo 27 of 59 Here is the nut removed. There is a star lock washer behind the nut.

    Photo 28 of 59 Now is where a specialty tool is needed. To remove the gear I’m using the supplied (was in my second kit, not in my first) gear/wheel puller. NOTE
    All four…drive gear, clutch gear, clutch assembly and magnet have woodruff keys. There are (2) different sizes. The magnet uses the one that is different in thickness.

    Photo 29 of 59 Removing the drive gear with the puller.

    Photo 30 of 59 Drive gear removed.

    Attached Files:

    • 06.jpg
      File size:
      112.4 KB
    Last edited: May 29, 2010
  3. Bonefish

    Bonefish Member

    Thanks, I do not have that speciality tool. It didn't come in my kit. The reason why I'm trying to take it off is because I think I might beable to use it for another project I'm working on, that right now is at a standstill unless I can find a sprocket, or i'll have to wait and call Staton and get one, but it would probably be until at least Tuesday before it would get shipped out because of the holiday. So I was hoping on trying to use this sprocket off of a blown china engine I have laying around.

    My project is an Old 6.9-to-1 Staton Right hand gearbox that i got of a guy that had it mounted to a gocart.

    The outdrive shaft on it is 5/8" bore with a 3/16" keyway. I was hoping on running it to the new Sick Bike Parts freewheel cranks I have that use 1/2 x 1/8 BMX chain.

    Do you or does any one know of a different way I can get this sprocket off if I don't have a/the speciality tool?

    Also will this sprocket turn/run 1/2 x 1/8 bmx chain? (I think I read somewhere it would, that is why I figured I might try and get it off of the blown china engine)

    Is the bore 5/8"?

    The keyway looks less than 3/16", could I run a file inside the keyway and increase the size to accomodate a 3/16" key or is the hardness of the sprocket too hard?

    or Should I just wait and get the correct sprocket from Staton?

    Thanks for your experience,
  4. GearNut

    GearNut Active Member

    Use a tiny 2 or 3 jaw gear puller?
  5. Bonefish

    Bonefish Member

    I was looking at the chain measurements, and it looks like the only difference between 1/2 x 1/8 BMX chain, #41 Roller Chain, and #415 Chain is the chain width. I found a reasonable supplier of #41 roller chain sprockets with a 5/8" bore. Was wondering if I put the #41 roller chain sprocket on a grinder and grinded down the teeth width to fit 1/8" would that work to run the 1/2 x 1/8 BMX bicycle chain im looking to run from the output shaft of my tranny to the SBP freewheel cranks I have? Thanks,

    The difference in price is substantial. If I got a 1/2 x 1/8 BMX sprocket with a 5/8 bore from a supplier, it would cost me $14.00 + $11.00 for Shipping and handling.

    I found a Local supplier where i could get a #41 roller chain sprocket with a 5/8 bore for less than $6.00. It is hardened steel as well.

    $25.00 vs $6.00 and local?

    Would this work?

  6. GearNut

    GearNut Active Member

    For the price difference, it couldn't hurt to try it.