Sprockets Broken small chain engine sprocket

[tmotorbikepad]

I ended up having a tooth brake of on the small sprocket that is attached to the clutch (because of a fallen off chain). I ordered the new small sprocket but i am trying to figure out how to take of the broken one. Do I need to take apart the engine or can it just be taken of more easily?

 

[BiMoPed]

I ended up having a tooth brake of on the small sprocket that is attached to the clutch (because of a fallen off chain). I ordered the new small sprocket but i am trying to figure out how to take of the broken one. Do I need to take apart the engine or can it just be taken of more easily?

there should be a special threaded puller with your kit that pulls the engine 10 tooth sprocket and the 2 gears on the clutch side.
If you don't have one order it too

 

[tmotorbikepad]

Thanks for the help but I need a little more; I am not very familiar with how the threaded puller works. I got the tool attached to the threads on the 10 tooth sprocket but once its on good and i turn it, It only pumps the piston. I can't figure out how to make the 10 tooth sprocket release from the engine.

 

[wbuttry]

you need to get a piston lock to aid in removing the sprocket i think you can get them at small engine repair shops or maybe harber freight

 

[dougsr.874]

There was a thread on here somewhere that suggested using a piece of small dia. rope by removing the plug and inserting the rope just before the piston gets to top of stoke. I tried it once and it works, however besure not to put the rope to far inside the cyld. as it will get caught in the ports...

 

[wbuttry]

sounds like a winner to me

 

[tmotorbikepad]

Sweet, I think im going to try that rope idea. Im also still wondering how that small sprocket comes off? . Is it going to just pop off once the threads are twisted down or are there other necessary actions to take for getting it off?

 

[wbuttry]

im not really sure how it come off really i know it has a nut you take off and dont you use the puller that came with the kit and the bolt you turn should pull it off on the tool i think it is presure fitted with a key or something and when you put the other back on i think you tap it on if im not mistaken

 

[GearNut]

The rope trick works very well.
1. Remove nut and washer that holds sprocket onto shaft.
2. Remove center screw from tool and oil the threads on center screw.
3. Oil the threads on the tool and carefully thread it all the way in until it bottoms out inside the sprocket. Take your time as it is easy to cross thread the darned thing and you do NOT want that to happen.
4. Install the center screw of the tool back into the part you have threaded into the sprocket and tighten it well. The sprocket should either pop off or just slide off of the shaft as the center screw is tightened.



Keep a watchful eye out for the woodruff key (a half moon shaped bit of metal) and don't loose it. You will need to reinstall it when you install the new sprocket.

Edit:
Also, the tools have a hex on the outside of the portion that threads into the sprocket, gear or clutch to let you hold it with a wrench, preventing it from turning, while you tighten the center screw.

Using this feature of the tool allows you to use it without using the rope trick.

 

[monsterhobby]

I'm not sure if this can be done on a bike motor but on small scale 2 stroke engines I don't like to use a piston lock so I have used what they call a hydraulic seal. what you do is you turn the engine over till you can fill it thru the plug hole with gas and not have it go down the admission ports take a bit of patience but that seal spreads the load over the whole piston not just pressing in 1 place. again I have never tried it on a bike motor.