How Do I install PIn in Small the Gear.

Discussion in 'Frame Mounted Engines' started by will_start, Jan 23, 2008.

  1. will_start

    will_start Member

    How Do I Install this Pin into the Small Gear ??

    Hi All,

    My motor has had a failure...again.
    (been motorless 3 weeks now)
    The Clutch no longer engages the motor.
    I have a 70 CC 2 stroke Chinese motor.

    On The right side of the bike, when in sitting position.
    There is a large cover plate for the bikes gears.
    After undoing the five screws,
    there`s two large cogs that sit inside this plate.

    With clutch engaged and pushing the bike forward.
    The smaller cog goes round and round, and the bolt that goes into
    the cog stays still.

    The motor does not try to start when the clutch is out.

    My supplier gave me a small pin (for want of a better word) that goes in there.
    I have tried to install the Pin, but could not work out how it would install.

    On the small axle, that the cog goes on, there is slot in the axle.
    On the under-side at 5 0Clock, there is a small slot that this pin i guess would go into.
    The pin looks like a half a coin, but its twice as thick as a coin.
    Looks like a half moon shape.
    It's about 7-8mm long and about 2.5mm thick.

    The slot is the same length as the pin. The small cog has
    a slot for the pin. I tried the pin in the cog and it fits.

    I tried to get the pin to fit into the cog and then put
    it onto the axel, but no way I could see would make this work.
    I tried this for about 30 mins to no avail.

    I tried to insert the pin directly into the axle, but it would not fit.
    It seems like its like 0.25mm thinner.

    There has to be a way around this issue.
    Someone else must have seen this.

    If I've managed to break this pin,
    then someone else must have and has managed to fix it.

    I've thought of filing down the pin, so it will fit into the slot.
    but I only have one, and unlikely my supplier
    will send me another without causing grief.

    So, I thought I'd ask if you knew how to fix it.
    Have you seen this.

    All help appreciated.
    I'll take some pics if anyone needs it to help clarify.:cool:

    Best regards,

    Will Start
    Last edited by a moderator: Dec 15, 2015

  2. Papasaun

    Papasaun Guest

    I might have missed this but,,, Has this engine ever ran for you?
    For lack of a better word, this coin shaped object is called a woodruff key, they sometimes appear in hex shapes also.
    Have you checked to see of the slots where this key goes are both clean, and empty of all broken pieces?
    DO NOT file anything down until you confirm that you either have the wrong replacement part or your engine is damaged where this part goes.
    Pictures will help us, to help you.

    Last edited by a moderator: Jan 23, 2008
  3. ibdennyak

    ibdennyak Guest

    As Papa said, make sure the keyways are clean and undamaged. If everything is the way it should be, it will have an interference fit (tight) in the shaft, and the gear should be slightly looser. The idea is to insert it (fully seated) in the shaft, and slide the gear onto the shaft and over the key. If the gear has been spinning on the shaft, there is a good possibility that metal has been dragged into the keyway. Good luck.

  4. cooltoy

    cooltoy Member

    I know about that key you speak of. Try to picture how it works and you may have better luck. As you are pushing the clutch into place, the key gets pushed backwards. Thing is that as it gets pushed back, it raises upwards,and ends up being too big/tall/high and this is why you are having probs.Make sure it is very clean, also make sure that the slot that it fits into is also clean. As you place the key into the slot, keep it tilted with the end closest to you low enough for there to be room for clutch to slide over it.If you can just get it into place, a small tap with a hammer may help, along with the tightening up of the nut. This is a hard one to help you with in a post-sorry.
    Last edited: Jan 23, 2008
  5. will_start

    will_start Member

    Woodruff Key Install response, and video of install.

    Hey All,

    Thanks, Papasaun , ibdennya and cooltoy .

    I read each of your posts.

    Thanks for the woodruff Key term,
    better to call a thing by its proper name.

    This bike has been running, on and off for about 4 months, and I've
    solved more issues than I thought I'd ever have to.

    I saw a picture of the item in another post, so I now know my supplier is telling the truth.

    I will see if I can degrease the axel, and if that makes any difference.
    Also check for a build up of steel etc.

    I'll take photo's of everything, just for the record.

    I wrote that earlier,
    now I have sucessfully installed the key.

    I took pictures at each stage, and created a short vid of the install.
    music and all.

    This is on topic, and if you watch closely, shows the key inserting into
    the slot. I used a pair of pliers to push it in.

    Cooltoy, I also used a wrench and hammer. Held the wrench over the cog,
    and lightly tapped it in.

    The bike would then start, after about the usual 10 minute peddle=strain/session.
    So I guess next stage is looking for HOWTO's
    on making your bike start easier.
    As this bike takes me at least 1km to get going,
    and then conks out after about 2km of riding.

    I have a video, made from the pics I took.
    I will have to put it on UTUBE,
    as it won't upload through here.
    Also the pics themselves won't upload.

    I'll post that link when its done.


    Will Start.
  6. ibdennyak

    ibdennyak Guest

    If you solve that one, let me know. :) I personally have a three page list of things that don't help.
  7. Papasaun

    Papasaun Guest

    Most excellent news on your motor!
    These 2 stroke motors are a very simple design, and the expectations are very high that they work. But like most things today, and yesterday, some can be very troublesome. Some motors are just "perfect" right out of the box, some are not.
    I believe that by sticking to the basics you can figure out what is wrong with your motor. Basics,,, Air, Fuel, Spark. Check each one and verify that it is indeed performing as it should be. When trouble shooting it is all to often to just start replacing items when quite often all that is needed is a simple cleaning or adjustment.
    Fuel, verify that you are indeed providing a unrestricted flow of fuel to the carb. Small impurites have been found in tanks and carbs that will and do cause problems.
    Air, verify that you are indeed providing a seal at the intake and carb connections, and that the seal at the cylinder is solid. Choke working properly and the carb is assembled correctly. (clip on needle and the slide works correctly, float and needle valve functioning)
    Spark, verify that you are indeed using a spark plug that provides a good spark And that it is gapped to the correct size.
    These are the basics that seem to be over looked at the factories and are not caught in QC.
    What seems like the correct "fix" with these engines is often one of the basics! With a search of this forum you can find a vast amount of info and specs for all three of the basics.
    Please keep us informed of what you find as this does add to the info available. Already we have seen several members reporting on, Junk in the tanks, bad gaps on plugs and weak spark, leaking intakes. All these factors will add to your motor not functioning as expected.
    Also when trouble shooting the electrical system don't be afraid to disconnect the kill switch for a test, some of these units have proven faulty, as are some of the connections in the electrical system.

    The assumptions we made today, are the problems we discover tomorrow.

    Last edited by a moderator: Jan 24, 2008
  8. cooltoy

    cooltoy Member

    Good points papasaun.Thats the thing with 2 strokes, is it getting gas, is it getting air and is there a spark.
    If I were you "will start", I would pull the sparkplug first to see if it sparks,You would do this by leaving s/p hanging on top of head , so that you can see spark.
    A great way to find fuel probs. is to get one of those spray bottles from a dollar store and fill with your mixed gas/oil. Take off air filter and as you are starting the engine spray fuel into carb. If it starts, you can spray,spray,spary to keep it running. If this helps it run, you know it's fuel probs.This would be better if you had a pull-start but maybe you could get a pal to help,running beside you spraying the bottle, or even better, just pushing you. This will almost always start the motor if you have fuel probs.
    If all of this is of no help, I would next make sure the wires are OK,you could have a short or some other stupid ,goofy thing that you overlooked.
    As I think of your post I have to ask myself why you were messing with the key, was there a bad misfire/backfire? Could this have caused a timing issue?
    I will wait for more info,good luck! Also, did you use fuel filter, if not , do it!
    Last edited: Jan 24, 2008
  9. cooltoy

    cooltoy Member

    I agree Norman, I too would like to see more members asking for help. It makes it more fun to be here. I'm into free to air (FTA) satilites and man, that is about as fast paced as you can get. There are many times that you have 1500 members on at once asking "why did I lose channels" or whatever and before you know it , you have been on line for 10 hours. Thats what I love,helping others, while learning at the same time.
    I really want to see this guy get his bike running and know that "we" can do it!
  10. will_start

    will_start Member

    Hi Thanks for all the encouragement. I have a new carbie, that I am going to try,
    once I get my vid on YOUTUBE, you'll see why I wish to switch Carbs. Probably do the
    upload on the weekend.

    The carb may settle the bike down, who knows.


    Will Start
  11. will_start

    will_start Member

    In a Galaxy Far Far Away, or How to install a Woodruff Key Vid.

    Thanks cooltoy, I used to own an old VB beetle and sometimes when things were bad with it, the only way to start it was with a product called


    They still sell this stuff and if it made the out of tune Beetle start,
    then I have thought of buying it to try on the bike.
    Its like some sorta nitro mix, so it gets in and makes a bad, cold, or flooded
    motor start.

    To answe your Question:
    I was told by my supplier that the reason my clutch no longer engaged the motor was that I had broken the key. Probably due to pushing the bike from a
    stationary position, with clutch out, he said this is known to break the key.

    I remember doing this with a spark test.

    I like your idea however as I could surely customise a spray bottle
    to make it sit under the cross bar, and feed a tube into the carb side of the
    air filter.

    I'll try anything at this stage...

    As described previously,
    I tried the new carbie today, and it makes a better sound than the one in the vid (original carbie). but starting takes several goes at a steep hill, and then conks out after about 300meters riding.

    I am missing a gasket for the carbie to motor seal.
    so I think that may be the cause.

    Would a mower shop stock this gasket...

    If you check the below vid,
    it shows the woodruff key install
    also shows a couple of pics
    of the caliper method I used to
    get control of the choke.
    Its actually easier than using the normal choke.
    The caliper cost me $3 from a shop in Australia
    called The Warehouse.

    This was especially relevant to my bike,
    as it had a variable choke sweet spot depending on the slope of the rode
    I was on.

    Ok, I have collected my mobile phone camera pictures
    of the woodruff key install into a video on YouTube.

    Hope you like.

    This is on topic, and shows the key at its "installed"
    position of 12 O Clock. This varies dependant on the spin of the axle.
    As I mentioned in a previous post, was at 5 Oclock before.


    Will Start
  12. Scottm

    Scottm Guest

    rotflmbo. I hear ya' loud and clear. Go read the 12 steppers thread, it's usually something small.
    Everything that everyone has said is right on and doesn't leave anything out. Make sure the spark plug wire is fully screwed into the CDI and making a good connection. Check all your wire connections and dittos on disconnecting the kill switch.

    Yeah, the gasket will help. Just go to the auto parts store and get a roll or sheet of gasket material and make your own, that way you can always have some handy.

    Great team work guys.:cool:
    Last edited by a moderator: Jan 25, 2008
  13. cooltoy

    cooltoy Member

    Hi Willstart, I've made up my mind, that is one cool video and you have a lot of talent.
    Way to go guy! I'd always thought it was the other key, on the clutch, not that it matters but still, it just goes to show that a picture really is worth a thousand words.
    That product you name, I would not use "Quick start" kind of stuff if that is what this product is as the stuff can be very hard on an engine. On the other hand, there are times when we bang our heads against a wall and get to the point that......well, you I also do as Scottm, just get the paper and that way you have lots on hand for times of need.I have a couple of punches that knock out a nice hole for the 10 mil. nuts and I use a sharp blade to cut the other hole. I know that I have to change mine every few months as they tend to "blow". As for my spray bottle, I don't think I would do as you say, this is just a way to see if the motor will run without having to do a lot of work. If it runs this way, you know it's a carb issue or at least fuel related. I have that choke sweet spot as well, not always but there are times that, if I bog out, I give it choke for a second or two and it then winds out. Anyways, great vid and hope to see more! Oh, good music as well!
  14. srdavo

    srdavo Active Member

    Cool video!! great song choice.

    thanks for the look inside a happytimes.
  15. ibdennyak

    ibdennyak Guest

    Dood....that's impressive. Nice job. When MBc decides to remake Easy Rider I nominate you as creative genius. I'll also donate my bike. It ain't no Captain America....maybe colonel Alaska, but it'll do. And then Augie can have you make instructional dvd's. We'll be famous.

  16. will_start

    will_start Member

    5 things I'm left to try til happy times arrive.

    Thanks ibdennyak srdavo cooltoy,

    Thanks for nice comments on the video.
    After that I'm going to make another,
    had 21 views in 2 days, so obviously
    others have looked at it.

    Can you take the head off and the barrel off without having
    to replace the motor gaskets ?

    I still have a motor problem however.
    As its an unreliable ride.
    I would love this motor to be as reliable as my car.
    I guess for $200, you have to accept you spend time rather than

    I know its off the subject line but worth the update.

    5 things I'm left to try to make my motor run are:

    1. Carbie intake gasket.

    I "lost" its inlet gasket somehow.
    I'm going to try and source one from a shop, rather than online
    via supplier. I hate getting charged $8 delivery for a $2 part.

    2. Fuel filter. I once put on an inline filter and the motor
    just would not start, maybe it was a bad filter.
    Going to see if I can source one.

    3. Tanks/Valve filter and tank clean out.
    My supplier advised me to empty and clean out my tank with Methylated Spirits.
    and Once after doing that the motor actually started and ran.

    4. Replace Engine Barrel

    My motor came with a hole in the front of it about the size of a 10cent
    piece. (5mm high by 7mm long)
    I plugged it with metal cement and gasket goo, but feel it's probably
    a leak point. My supplier offered to replace it free.
    So I may take him up on that.

    5. Remove kill switch.

    I do my own stunts and soldering, and I saw someone say the
    kill switch can affect the motor performance if its faulty.

    What else can I try ?

    I know, Reading posts, searching etc etc.
    Done that, and am finding more info...

    One thing I wish to know,

    Can you take the head off and the barrel off without having
    to replace the motor gaskets ?

    As that would be something I need to do.


    Will Start
    (Living in Sydney, Australia)

    PS I'm glad I don't rely on this beast for transport,
    as I'd be doing alot of bus riding. I have a second bike,
    which since I got the motor has done 90% of my rides.
    One day I hope to get that figure down to 10%.
  17. cooltoy

    cooltoy Member

    I notice you are online now so I hope I can catch you now. Before going any further in trying to help you, I want to ask you why all the bother if guy is going to give you new case? Is there any leakage at the spot you "fixed"?
  18. will_start

    will_start Member

    RE: hole in motor.

    Hey cooltoy

    Well the barrell or case as you call it is on offer if I need it.
    the only reason he made the offer was in sympathy with my constant
    efforts to make the bike run.

    He said the hole would make no performance difference
    and BTW those 5 things are about 30 % of the things I've tried.

    The barrel replacement question still stands,
    Do I need to replace the gaskets, if I am to pull it out.

    I have not seen any leaks from that "fixed" hole, so feel its working...

    I've been told once you if undo an engine all gaskets are then useless,
    and must be replaced, but that advice could be only relevant to
    cars etc.

    I have found it hard to seperate fact from myth with the people
    I have spoken to about motors.

    Today I bought a sheet of gasket paper, so I'm going to make my own
    inlet gasket and try that. (point 1).
    also bought an over-sized fuel filter (point 2),

    Was so tempted to buy that aero-start product.
    Here's a link to it:
    It works on faulty old cars too.

    But I'm holding off until its the last resort.
    Anyone tried this or similar products ?

    To quote some else:

    Will Start
  19. cooltoy

    cooltoy Member

    Glad to hear you got the gasket paper,just take your time when making gasket. There will be some that may think I'm nuts but I see no probs with re-using your gaskets as long as they are in good shape. I'm going to guess that the lower gasket is paper but I could be wrong. If it is paper, make sure it did not get all streatched out of shape when it was removed.I think this one would tend to glue itself to the metal. The reason I asked if the repair you did on the block was leaking is because there is pressure in there. if no leak, thats great,leave it.As for the fuel filter, make sure you install with arrow pointing in proper direction. I guess you could say that the arrow should point towards the carb. I think that could have been your mistake with the last one.That is a very important thing to use as a bit of rust or **** can really scratch up your insides.
    I hope that covered everything, if not just ask away!
  20. will_start

    will_start Member

    gasket paper

    thanks for the advice,

    I had a choice of paper or cork paper,
    I chose the cork variety, as it was thicker.
    which hopefully equals a better seal.

    How would I know if there's a leak or not ?

    I returned the previous inline filter, as the bike just stopped
    after I installed it, and yes the arrow was in the right direction.
    I'm going to see if I can get the bike running and then install the filter.

    Change too many things at once, and you don't know which one fixed it...