Sprockets Filing down the drive sprocket?!

Discussion in 'Transmission / Drivetrain' started by MichaelSteve, Dec 3, 2007.

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  1. MichaelSteve

    MichaelSteve Guest

    Hey guys,

    Been putting together my first motored bike using a 48cc kit from www.zbox.com.au. It has gone relatively smooth so far, but now I'm attempting to install the drive chain, and I am finding that it doesn't fit around the small engine drive sprocket properly and gets jammed in there when attempting to wind it on.

    The chain fits around the rear sprocket just fine.

    In the instruction manual it says to file down the sprocket for 'smoother running'., and also i presume - to make it fit. Has anybody here had to do this? I'm kind of reluctant to just go at it with a file in hand.

    Any ideas?

  2. fetor56

    fetor56 Guest

    That guy Warren from ZBOX doesn't seem to have much of an idea about chains(or sprockets)...i complained about the stretch in the crappy Chinese chain and he was very defensive saying it was a good chain.......rubbish.
    Your chain should fit from new but since it doesn't their are a couple of things u can do:
    1.Buy a different sprocket and NOT use that wierd Chinese sized sprocket.I havn't tried this but overseas websites sell updated countershaft sprockets that fit.
    2.Buy a different chain that fits both standard Chinese sprockets.....i tested MANY chains and found that the KMC 415H Motorcycle chain fits nearly perfectly...i also understand the YBN 415H Motorcycle chain also fits.
    3.Angle-grind the sprocket where u think it's riding-up.I'm afraid i can't help u there because my chain fitted well from new and so does my replacement chain.
    4.Email Warren and tell him your problem and let him sort it out....it's rather pathetic that something doesn't work from new.

    Also,get yourself a good chain-tensioner...the one Warren supplies doesn't have ball bearing construction and needs constant attention.
    Good luck man. :smile:

    See my pic for tensioner:
  3. fetor56

    fetor56 Guest

    PS....MBB-Imports in NSW sell countershaft sprockets....dunno if they fit though.
  4. Im glad you guys started this topic as Im at this stage now. I was waiting for my son to go to bed and was planning to pull the cover off to grind down that gear (on Warrens' say so).

    I guess thats on hold now to see what everyone else says.

    I dont really want to import a new gear at this stage. With it so close to Xmas, the timeframe stretches out. I might check out my local BSC tomorrow to see if they can help.

    Keep us informed

  5. MichaelSteve

    MichaelSteve Guest

    Cheers for the info Fetor,

    Have emailed Warren to see what he says - which I assume will be "grind it down, she'll be right, mate."

    Kind of don't want to do that, but will see what happens. Nice to see someone has the same problem as me though. Looking at you Leigh. :D
  6. MichaelSteve

    MichaelSteve Guest

    Hey guys,

    Got an email from warren;

    "Dear Mike,

    I have had another 4 or 5 similar problems from that batch of 200 units. I shall put a replacement drive sprocket in the mail to you in the morning. It's easy to swap with the black screw tool included in the kit.
    sorry for inconvenience - kind regards from Warren Bates
    ZBOX Australia
    PO Box 113, Bellingen 2454
    Tel: (02) 6655 2920
    Email: info@zbox.com.au
    Website: www.zbox.com.au

    So there ya go.
    I guess if anyone else if having any issues similar to ours with zbox kits, they should email warren and let him know.

    Hopefully this is the end of this problem.

    Cheers for the help fellas,
  7. fetor56

    fetor56 Guest

    Good to see that Warren is standing by his product.
    It is easy to remove the sprocket with the supplied tool(remember to have the chain on or partially on to remove/replace the retaining nut)
    The potential problem is when your finished and want to tighten the retaining nut....it's on a tapered spline so it's easy to think that it's tight when it actually isn't.Check it a few times for tightness...........tight...not radicously tight.
  8. 5-7HEAVEN

    5-7HEAVEN Guest

    :cool:I'm in your same situation, but I'm trying to mate the drive sprocket to bicycle chain and 7-speed cassette.:confused:

    The stock bicycle chain meshes correctly on every other link. Every other link is narrower, so rides up on the drive sprocket.

    Now I realize why another member's chainsaw engine kept throwing the chain. His drive sprocket was also linked directly to his cassette.:confused:

    I ordered a special sprocket from DAX. It's listed as being 1.5mm wide, or less than .060". If this sprocket doesn't work, I'll look for a chain that is more compatible.

    Grinding the sprocket's teeth is the last resort for me.

    Last edited by a moderator: Dec 3, 2007
  9. Bean Oil

    Bean Oil Guest

    Hey, MichaelSteve, if you're any good with a digital camera, would you please post close-up pics of both the old and new sprockets?

    And who here can suggest which aspect to file from the sprocket? It's thickness, or it's chain teeth? I haven't looked directly at mine, having just fed it onto the bike last night where it did exhibit a slight tendency to jam...


  10. Usually the teeth have to be filed so they are slightly more "triangular" when viewed on edge....mostly towards the tips tho (sprocket teeth facing your nose.....Profile view)
  11. Bean Oil

    Bean Oil Guest

    Thanks, Andy... I think I know what you mean. :D

    You mean looking straight down onto the top of a tooth and adding a bit more taper but just the 3/16 to 1/8 near the tooth's tip?

    Difficult to describe without pics...

    Last edited by a moderator: Dec 3, 2007
  12. i noticed someone was talking about how the tensioner doesnt spin, get a faw washers and you'll be fine

    quote"Also,get yourself a good chain-tensioner...the one Warren supplies doesn't have ball bearing construction and needs constant attention.
    Good luck man."unquote
  13. HI Bean,

    Yes, I believe you have it...the taper goes from the thin side of the sprocket to the other thin side is about how I'd describe it....I will try to post a pic later if you need but I'll have to take a picture of a rear sprocket but the idea is still the same for the front sprocket.


  14. MichaelSteve

    MichaelSteve Guest

    Just incase anybody is interested, here are Warren's instructions on how to remove the drive sprocket:

    " * Slip out the bucking bar (loose rod that pushes the clutch in).
    * Use plug spanner to remove large nut.
    * Screw the screw tool into inner thread of small sprocket
    * Turn the inner piece of screw tool clockwise to lift out the sprocket
    * Put new sprocket on and lightly
    tap into place (be sure to keep key in the slot)
    * Replace large nut with plug spanner and slip bucking bar back into place.
    * Put a dab of grease on bucking bar and sprocket whilst you have it all open.

    That all should take you 5 minutes and you will have no problems afterwards."

  15. MichaelSteve

    MichaelSteve Guest

    Hey guys, little problem.

    Got my new sprocket, went to take the old one off. Managed to get as far as taking the nut off thanks to this thread:


    Now I'm attempting to use the screw tool to remove the sprocket, but for the life of me I can't stop the engine from turning over. As soon as I tighten up the bolt, the whole thing just starts spinning in the breeze.

  16. fetor56

    fetor56 Guest

    Stop it from spinning by placing a 22mm spanner(or adjustable shifter) around the lower part of the removal tool and while holding that securely turn the 14mm bolt...you'll see where it's meant to fit.

    PS...also see my other post about making sure the sprocket nut is tightened securely.
    Last edited by a moderator: Dec 6, 2007
  17. Bean Oil

    Bean Oil Guest

    Dumb Q, but did you remove the clutch "bucking bar"? Either way, I think you still have to hold the sprocket from turning (obviously).

    Okay... I go now. :p
  18. MichaelSteve

    MichaelSteve Guest

    Oh god nevermind, I must have been way too tired last night. Got up this morning and figured it out, then came on here and realised the stupid question I asked.

    Cheers guys,
  19. gone_fishin

    gone_fishin Guest

    wayfastwhitey69: consider this your second friendly reminder to follow forum rules...deleting and evading won't work with me, as you may soon learn.

    please, introduce yourself, just like you'd be expected to in real life.
  20. Alaskavan

    Alaskavan Guest

    The sprocket on my motor is 1/4" thick, the rear sprocket is 1/8". I'm assuming that running 420 chain won't work. Any suggestions? I've been looking around and haven't found a front sprocket for 415 chain that will fit the splined shaft on the motor. I'm kinda inclined to fasten the sprocket in a drill press and take a good grinder to it.