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Scooter knocking sound

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chaza
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Joined: 02 May 2018
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PostPosted: 22:15 - 05 Jan 2019    Post subject: Scooter knocking sound Reply with quote

Hi guys
I have a Chinese scooter, thd variator seems to have a knocking sound. The part is new so I wondered could it be variator weight issue. The scooter pulls away immediately you have no Rev room.
So I'm not clear about the weights, can anyone shed light on this issue please.

Thanks
Chaza
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Riejufixing
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PostPosted: 00:28 - 06 Jan 2019    Post subject: Re: Scooter knocking sound Reply with quote

chaza wrote:
can anyone shed light on this issue please.


Symptoms rather vague. Did you replace parts? What parts? Why?

A video clip would be a useful thing.
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andy46
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PostPosted: 10:45 - 06 Jan 2019    Post subject: Reply with quote

From the limited info you have given I would guess that the variator is stuck partly (or fully) open. With the engine not running remove the belt cover and look where the belt is sitting in the variator - if it's sitting well inside the "V" pulley of the variator (and/or the belt appears very slack) then it is stuck open. This can be caused by one or more of the rollers or weights not being properly positioned when the variator was fitted (or they can just stick due to poor manufacture, or due to being worn - but yours are new).

A stuck open variator will cause the problem you describe, the knocking noise would be the other rollers rattling around in their "cage".

Removing the variator, re assembling and refitting may solve it and is worth trying - check for obvious signs of damage to the rollers while they're out.

There are plenty of youtube videos showing how to replace the belt and how variators go together - you'll need some kind of impact wrench to get the variator nut off and to do it up again (air or battery)

Who fitted the new variator?
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chaza
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PostPosted: 14:06 - 06 Jan 2019    Post subject: Reply with quote

Hi guys
The variator is brand new, I chsnged it because in thought it might be the cause of the noise, so now I'm wondering if the weights are not right, the throttle leaves no room for slight revs, it's instant, so maybe the weights need changing for different Rpm.
What do you think.

Chaza
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Northern Monkey
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PostPosted: 17:19 - 06 Jan 2019    Post subject: Reply with quote

Could the power band be worn, or the wrong colour power band installed?
____________________
Fisty: after polishing the tank with the glistenng beads of sweat from my full hot scrotum, I filled the headrace bearings with 10cc of my manmilk
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chaza
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PostPosted: 17:52 - 06 Jan 2019    Post subject: Reply with quote

I can't answer that, but I'll check
Thanks
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andy46
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PostPosted: 20:15 - 06 Jan 2019    Post subject: Reply with quote

When you fitted the new variator did you also fit new rollers (weights)?
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chaza
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PostPosted: 20:37 - 06 Jan 2019    Post subject: Reply with quote

Yes.
But now I'm concerned about the weight v rpm
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andy46
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PostPosted: 21:13 - 06 Jan 2019    Post subject: Reply with quote

I doubt that it's a weight issue if its all new and fitted correctly.

Is the scooter rideable - I'd have thought it would stall if it's trying to pull away at low revs?
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Riejufixing
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PostPosted: 23:43 - 06 Jan 2019    Post subject: Reply with quote

Perhaps the rollers are in the wrong way around, or there's something missing, not done up, or in the wrong place.

"A video clip would be a useful thing".
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chaza
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PostPosted: 00:12 - 07 Jan 2019    Post subject: Reply with quote

The scooter is rideable, she runs fine, it's just the noise, I first thought it was the crank bearing, but now I'm not sure, the noise is around the variator. So now I don't know.
I'll take the cover off and see how things are working.
The weights are round, how can they be in wrong.

Cheers guys
Chaza
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Riejufixing
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PostPosted: 01:48 - 07 Jan 2019    Post subject: Reply with quote

chaza wrote:
The scooter is rideable, she runs fine, it's just the noise, I first thought it was the crank bearing, but now I'm not sure, the noise is around the variator. So now I don't know.
I'll take the cover off and see how things are working.
The weights are round, how can they be in wrong.

Cheers guys
Chaza

The rollers are often fitted only one way around. It might not cause the noise, but might cause premature wear of the thrust end. Worth checking anyway[1]. Look carefully at the ends of the rollers and check which way around they go in the manual. Also check that the (3) plastic guides are present and correctly fitted and that the variator nut's been tightened properly.

The drive side main bearing is just behind the variator. To check, remove the variator and the magneto flywheel from the ends of the crankshaft. Remove the sparking plug. Rotate the crankshaft in stages and feel for any radial movement (both crankstaft ends) at various points.

Edit: You can use an "engine stethescope" to listen to various parts of the engine when it's running. A long wooden spoon, stick, or screwdriver is ideal. Put the "sharp end" against the crankcase where you want to listen to a component, e.g. a main bearing, with the engine running. Be careful of any rotating parts (and the HT side of the electrics of course!) Put the "blunt end" against that sort of triangular flappy bit just in front of your ear's hole, and push against the blunt end so that it pushes the flappy bit against your ear's hole to close the hole. You will hear all sortis of interesting noises from various parts of your engine. A worn main bearing gives a slightly grinding fast swishing sound.

[1] https://www.adrenalin-pedstop.co.uk/Tutorials/Tutorial8.aspx
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chaza
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PostPosted: 11:11 - 07 Jan 2019    Post subject: Reply with quote

Thanks for that, I'll get on it

Cheers
Chaza
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chaza
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PostPosted: 22:08 - 10 Jan 2019    Post subject: Reply with quote

Thanks guys
The bikes are garaged now till spring, I'll get to it then when I know more.

It's all appriciated
Thanks
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