cbt passed 1/2mile down the road chain snapped.

[AndyB1989]

hi guys ,

got a cheap shitty 125 the other day china special .. passed my cbt today and went out for a ride got less then 1/2 mile form my front door and the chain snapped .

ive come home and stripped it apart and the front sprocket has quite ALOT of free play it wobbles side to side quite alot is this the problem ?

[CarlosCBR]

Hmm typical chinese build quality. Is there not a spacer of some sort between the sprocket and bolts? How much wear is there on the sprockets?

Its probably not the cause but it still needs looking into. Do you know how loose the chain was before it snapped? Personally i would change the lot and see how it is after that.
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[Teflon-Mike]

Normally Honda copy motors, and the generic small honda sproket mount.
Sprocket slides onto the output shaft on splines.
An oval plate with spine tanks goes on after it, and has to be twisted one spline width in a groove to alingn the holes in the ends of the oval with the holes in the sproket, to take teh screws that lock teh assembly together & Stop the sproket falling off the shaft.
There's normally about 1mm ish of 'play between the retaining plate and the groove... but if the sprokets not bolted to the retaining plate or the retaining plate is missing?
However, the sproket would normally 'self centre' in the chain, so unless it was wobbling hugely and teh chain monsterously slack, I wouldn't expect the chain to jump the sproket, and even then, for that to cause the chain to snap.
Chains stretch.... cheap chitty chinese chjains stretch a lot....
Chains second hand cheap chitty chinese things get stretched, and when the chain reaches the end of teh rear wheels ability to adjust out the slack, some smart arse suggests knicking a couple of links out of it to make it shorter....
The 'pitch' of teh chain is now increasing alarmingly, as the gaps between the pins increases with the stretch... but the gaps between teh teeth of teh sprokets, often wont be increasing by anywhere near as much.....
and at some point the mis-mesh means that the sproket picks up on the peak of a tooth, not a valey between teeth, and 'chucks' the chain....
This stretches teh chain even more, and canm stress teh side plates.... and its THAT which will make teh side plates actually break.

In short... y'chains fucked! Get a new one!
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[AndyB1989]

closer inspecction .. the chain hadnt snapped it had jumped and when i tried to unjam it i twisted and snapped the "master link" the cause of the jumping chain

the adjuster for moving the rear wheel backwards on one side of th swingarm snapped a weld on the captive bolt causing the wheel to wobble and throw the chain


adjuster is being weldedd tomorrow i will replace the chain and sprockets in due course but for now my neighbour who is a biker and whose judgement i trust says the chain looks good and not particularly worn so i will get a new "master link" for it and put it back together and get it tensioned up properly again

[devojunior]

even if you took the adjusters off the wheel should stil not move