Vibrating Bike is it the chain? ** FIXED*** :)

[shammon]

I intend to replace the sprockets and chain on my cg125, but had to stop using it as it was vibrating badly! engine revs on its own ok and when i pull the clutch in when riding it rides straight and normal soon as i use the throttle it hates me, is this normal when the sprockets & chain are well gubbed?
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YAMAHA YZF 1000cc THUNDERACE- 'ƃuıןןǝds ʇnoqɐ ʇıɥs ɐ ǝʌıƃ ʇuop ı

[Kickstart]

Hi

Could be, but a bit strange that pulling the clutch gets rid of it entirely (after all, the chain is still turning).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Finglonga]

Yea sure sounds weird? I would check the basics like how tight the chain is (with you sitting on bike) and wheel alignment. Also check the nuts holding the sprockets on, have you tightened them all up or have they come loose again? If its only started since fitting the new chain and sprockets it must be something you did while fitting them, just check everything over again.
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Andy Sez....
F.Y.Y.F.F.

[mchaggis]

A vibrating engine problem on my Mum's CG turned out to be a combination of a knackered front sprocket and piston slap. A new sprocket, new piston and honed bore fixed it. The first bit is simple to sort out to see, the latter would be a little more expensive.

A knackered front sprocket wouldn't necessarily being doing the hop, skip and jump if you aren't putting a drive torque through it (i.e. if you have the clutch in). Check it to make sure it hasn't got hooked teeth, and check the chain to make sure it hasn't got stiff links. As it's a split link jobby, it's simple to take it off to clean/ lube it properly.
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I must not be a troll...
Mmmm, Guinness
Discovering the delights of Hammerite and a 3/4" brush.

[shammon]

Well i ended up today getting dirty, With the bike You were spot on,.... the front spocket was wobbling! so worn on the outer and inner cog fixture, will have to wait for the parts to come but i hope thats the prob. engine runs fine. Also removed the rear cog and checked the rubber bushed which were ok. il get a piccy for others to see.
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YAMAHA YZF 1000cc THUNDERACE- 'ƃuıןןǝds ʇnoqɐ ʇıɥs ɐ ǝʌıƃ ʇuop ı

[shammon]

fitted new spockets and chain, and the Bas*ard still is vibrating but not as bad as before. checked all over and it appears there is still some slight movement side to side on the front sprocket I did not replace the front sprocket bracket which retains the sprocket onto the drive shaft. so will have to try this before i give it a kicking.

My fear is the drive shaft raised points which stop the sprocket comming of could be worn due to the previous one? and therfore with me fitting the new one it will stil have play. heres a pic of the sprockets for any one intrested with a cg.
https://i7.photobucket.com/albums/y277/shammon/mini-DSC05024.jpg
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YAMAHA YZF 1000cc THUNDERACE- 'ƃuıןןǝds ʇnoqɐ ʇıɥs ɐ ǝʌıƃ ʇuop ı

[veeeffarr]

Have you checked that this engine bolt (Circled in red) hasn't snapped? This is what happened to mine when it was making a vibrating noise.

https://www.bikechatforums.com/files/enginemountbolt.jpg

[Kickstart]

Hi

The front sprocket is rarely a precision fitting. Generally there is a bit of movement there.

Above comment on the engine mounts is well worth following up.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[veeeffarr]

Its not easy to tell its snapped, I didn't think anything of it but my attention was drawn to it when the nut fell off, the easiest way to tell is to take the nut off and see if the bolt moves backwards and forwards, this didn't mean anything to me until the guy in the garage told me my 4 month old vibration problem was in fact this bolt snapping.

[shammon]

Thanks Keith & Toby il have a check today for possible snapped bolts
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YAMAHA YZF 1000cc THUNDERACE- 'ƃuıןןǝds ʇnoqɐ ʇıɥs ɐ ǝʌıƃ ʇuop ı

[shammon]

Thanks Toby it was the bolt you spoke about, It was not snapped but loose enough to causethe engine to move and vibrate bad. The bike rides so much better and the gear change is more smooth.

Thanks to all
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YAMAHA YZF 1000cc THUNDERACE- 'ƃuıןןǝds ʇnoqɐ ʇıɥs ɐ ǝʌıƃ ʇuop ı