How to remove engine sprocket. - drive sprocket - pic

Discussion in 'Frame Mounted Engines' started by The Hornet, Apr 13, 2007.

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  1. The Hornet

    The Hornet Guest

    I am going to be replacing my engine sprocket this weekend and had a few questions.

    I heard that you have to remove the clutch arm and ball bearing this true?

    How do you keep the engine from turning over while you loosen the nut?

    Do I have to use that wierd tool that came with the kit?

    Any other surprises?

  2. azbill

    azbill Active Member

    it is very important to take out pin ... ball bearing is ok but if you leave pin, it will damage clutch when you tighten gear puller (it pushes pin n bearing too far and bends the clutch plate allowing bearing to get jammed)
    I did that and that is why azvinnie's trike is now electric :eek: :(
  3. srdavo

    srdavo Active Member

    I have NEVER removed my front sprockets.

    Inside the shaft, where your front sprocket is attached, there is a clutch pin & a ball bearing. I believe you should pull the clutch pin out before you try to pull your sprocket. (sometimes the ball bearing will roll out...sometimes it won't. )
    Yes, time to use that funny tool that came with your kit. If you leave the clutch pin in the shaft, the sprocket puller will have to push the pin a long way before the puller ever makes contact with the shaft. this will probably stress the moving parts on the clutch side.
    when you screw the puller into the sprocket, use a wrench to make sure it is seated snug. ya don't wanna pull any threads loose.

    ok....gearheads, jump in anytime now...... :)

    as for loosening the nut....I'd do that while the chain was still routed to the rear wheel. then you could hold the wheel to keep your engine from turning, if needed.
  4. The Hornet

    The Hornet Guest

    OK...before I get REALLY confused...

    I am talking about the sprocket that the chain runs around that is mounted to the motor, not the big sprocket with the clutch attached.
  5. srdavo

    srdavo Active Member

    that's the same sprocket we're talking about. the pin pushes thru to the otherside of your engine to disengage your clutch. do you follow?
  6. thatsdax

    thatsdax Guest


    Remove the metal dowel in the center of the sprocket. Use an impact to remove nut. Put sprocket removal tool on to sprocket. Use impact wrench to pull sprocket. Done..
  7. The Hornet

    The Hornet Guest

    What if you don't have an impact? Can you keep the motor from turning over if it isn't mounted in the bike?

    I see that we are all on the same page now....
  8. azbill

    azbill Active Member

    if you put a wrench on the nut , you can give the wrench a quick smack with a hammer and it will loosen the lock washer/ring under the nut ...then it will come off easily :D :D
    I read that on another forum and it worked when I did it
    when re-installing , make sure the teeth on lock-ring bite into nut not engine or it won't stay tight
  9. srdavo

    srdavo Active Member

    I tried this last night....It works just like you said. Also, the puller worked great, using regular wrenches. no need to run out & buy any impact tools! :D
    Hornet; there is a piece of keystock that fits in both the sprocket and the engine shaft. Be careful not to lose it when you take things apart.
    Let us know how it goes for you.
  10. The Hornet

    The Hornet Guest

    Will do...thanks to everyone who helped out!
  11. The Hornet

    The Hornet Guest

    The operation was a problems at all. I am going to wait until the bike is together to tighten up the nut so the chain will keep the motor from turning over.

    Thanks again!
  12. gone_fishin

    gone_fishin Guest

    drive sprocket removal tool
  13. Irish John

    Irish John Guest

    This is the funniest comment I've read on MBc. Sad about the motor but very funny to read.
  14. azbill

    azbill Active Member

    I hope this thread helped ya dude :)
    I have done it numerous times now...and it is just that easy
    we ended up beating his dead engine into pieces with a sledge :lol:I felt better after doing it too ! :D
  15. Irish John

    Irish John Guest

    Great Help Azbill

    This page has been really good so thanks Azbill and special thanks to Fetor 56 who explains everything simply in Ozspeak.
    Oh yes, I'd have sledged the motor to death in your garden too if you'd told me where you lived. I'd love to go into the Chinese factory with my Percy Sledge and take a few swings at the guys in the precision engineering dept.!
    Last edited by a moderator: Mar 25, 2008
  16. Irish John

    Irish John Guest

    I'm stuck

    I've got the nut off and the special tool is in the sprocket as per attached photo.
    The outer ring of tool is screwed tight to inside ring of sprocket. The middle bolt of tool doesn't want to screw in much further than shown. What happens now?

    Attached Files:

  17. hellbilly

    hellbilly Guest

    Just crank down on that middle bolt and the sprocket will come off.:grin:
  18. Irish John

    Irish John Guest

    Done it

    Thanks Hellbilly, Fetor56 told me to put a 22mm spanner on the big one and hit the 14mm one hard with a rubber mallet.
    I have eventually replaced the sprocket but they are all badly engineered sprockets and the first 100km makes me sick listening to the chain stretching and grinding over the sprocket. Poor Japanese chain being subjected to that sort of abuse. The supplier says I can file the sprockets down so they don't do that but that's like being sold a pair of trousers three sizes too small and being told to not eat for 6 months so I'll fit into them.
  19. BoltsMissing

    BoltsMissing Active Member

    Howdy Irish, hope I have not got to this too late.
    I noticed the engineering of the sprocket is what it is, ( and thanks to Fetor who helped at the time to.)

    What I did was sort of ran my finger on the edges of the sprocket teeth and if it felt like it was cutting skin,which it did, I would take my time and simply use a very fine file to take out that razor like sharpness.
    I improvised a bit by using 2000 wet&dry with oil, and I used the wire brush part of my bench grinder to give it a bit of a polish.

    Then I ran the chain through the teeth and just try to visualize what it will be doing when it's all working.

    But get rid of the sharpness on the edges of the sprocket where the chain engages.
    It ought to feel like a smoth run and no need to use band-aids to stop the bleeding off ya fingers !

  20. Irish John

    Irish John Guest

    Thans Bolts

    You're right Bolts but I need a vice to hold the sprocket while I'm working on it. A grinding polishing tool like what you have would be great too. I'll use a friends one but in the meantime I'll leave the sprocket on and let it wear its edges off on one of those lousy 415 chains that come with the kit. It's so annoying that the sprockets aren't cleaned up in the factory and it is positively dangerous to supply them in the state they do given that they are such a critical part of the drive train. The old sprocket (1 week old) I'll do as you recommend. When the sprocket has worn good I'll put on a nice Yaban 415 chain or an extreme BMX chain. Both those chains are light and delicately engineered so are thinner than the usual 415 ones. I find the thinner chains are so much smoother to ride with