Strange noise coming from Transmission ?

[scooterfan]

A couple of days ago I started another thread - mentioning a strange noise and slight vibration which I thought / hoping was coming from a worn wheel bearing. I thought the noise was coming from the front wheel bearings - so both bearings have been replaced with new ones. No improvement at all - the noise and slight vibration did not disappear.

Something I didn't mention at the other thread - the original clutch pads at my scooter got very thin and has been replaced with a 2nd hand clutch which came from a Chinese scooter. The 2nd hand clutch is still in good condition, has the same size, and matched the Kymco pulley assembly perfectly. The strange noise and slight vibration actually started immediately just after installation. Just before the 2nd hand clutch was installed there was no noise or vibration at all.
After a short initial ride the clutch has been removed again for inspection . Everything including the two clutch bearings seemed to be perfect - therefore I thought maybe by fluke some of the wheel bearings might be on it's way out.

It might make sense to have a look at the rear wheel bearings as well, but I started having a feeling the noise and slight vibration might have something to do with the 2nd hand clutch or CVT system. At the time when the worn clutch was removed I didn't have the correct size socket or spanner to remove the nut - so I took it to a local scooter shop. One of the mechanics  clamped the pulley in a vertical position in a bench vice, and loosened the nut with a vice grip. I am not sure whether the pulley got  bend or damaged while being clamped in the bench vice - so probable have no choice other than stripping the CVT assembly again.

For the time being I would appreciate any comments. Did anyone ever experience a similar problem ?

[Stig / Major Tom]

Yes, he might have tweaked the pulley.
As for removing the large, thin nut holding together the clutch assembly - best removal video involved using an adjustable wrench (or vice grip) on the nut, hold clutch in hands and tap wrench end on ground. Pops loose the nut without drama.
Stig

[scooterfan]

Yes, he might have tweaked the pulley.

I've had a proper look at the pulley today. Fortunately it's not been tweaked at all. It looks like the two wheel bearings and at least one gearbox bearing need to be replaced.  The axle- and clutch shafts both had some slight play when tested by hand.  I started thinking the Chinese clutch might be slightly off balance - which could cause the noise and slight vibration but I'm not sure.

For the time being I need to find a way to remove some gearbox bearings. Some bearings are located very close to the sidewalls of the gearbox housing and I'm not sure whether a suitable bearing puller will be available locally.

[jeeves]

I've had a proper look at the pulley today. Fortunately it's not been tweaked at all. It looks like the two wheel bearings and at least one gearbox bearing need to be replaced.  The axle- and clutch shafts both had some slight play when tested by hand.  I started thinking the Chinese clutch might be slightly off balance - which could cause the noise and slight vibration but I'm not sure.

For the time being I need to find a way to remove some gearbox bearings. Some bearings are located very close to the sidewalls of the gearbox housing and I'm not sure whether a suitable bearing puller will be available locally.

I replaced the wheel bearing on the gearbox and rear axle. Didn't have a bearing puller so I pushed them out like on the picture. Worked ok.


Like this:



You will need a new gearbox seal and bearing seal.


Puting new bearings in was easy. I put the bearing in the freezer at -18c for about half an hour. A few minutes before installing it I heated up the part where it goes in using a paint remover heat gun.
It just drops in with a little push at the end. Seats immediately.
Wear gloves so the bearing doesn't stick to your fingers.

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[scooterfan]

@ jeeves.

Thanks, the threaded rod "puller" is a very good idea. I have an ordinary puller but I actually knocked the bearings out by using a piece of round bar and a hammer.

The puller I needed is actually the "blind" type like the pullers at the image below. The inner wheel bearing which can been seen at the far left of your last photo sits right next to the gearbox housing and an ordinary puller or threaded rod can not be used to remove that bearing. A "blind" type puller is needed to remove that bearing -  but those pullers are only available in sets locally. Very expensive - a set of those pullers would cost me about one third of the price I paid for the scooter.

For the time being only the two sealed bearings inside the housing have been replaced. The two shafts which had a little play when tested by hand has no play any more and I thought the noise and slight vibration would be gone - but no luck, the noise and vibration didn't disappear. For the time being I will just use the scooter as is. I still think the Chinese clutch might be slightly off-balance and hopefully the noise and vibration will disappear by time.

A photo of the blind type pullers can be seen below.

[scooterfan]

@ jeeves

By the way - having had a look at your last photo I actually thought the design or your gearbox is much better than the design on my Agility's gearbox.
I usually fill gearbox oil right to the top of the filler hole. If you have a look at the position of the filler hole on my Agility's gearbox (photo below), you will see that the oil level hardly gets in contact with the big bearing at the far right. This obviously means that that bearing on my Agility is very dependent on oil splash inside the gearbox.
In your case - the bearing at the far right will be partly submerged in oil when oil gets filled right to the top of the filler hole.

Right or wrong - when I filled gearbox oil yesterday I decided to lean the scooter over to the right, and I added another 70ml of oil to the gearbox. Just to make sure the bearing at the far right will be properly lubricated at all times.

Just as a matter of interest - what model and year model is your scooter, and do you also fill the gearbox right to the top of the filler hole ?

[jeeves]

It's a 2008 Agility City 125.
I fill 0.18 liters.

More oil will probably cause more resistance of the gears turning inside, and the excess oil will end up in the  variator via the tube that is connected between the gearbox and variator. It happened to me a few times

I think the splashing of the amount of oil as stated by Kymco should be enough to keep all bearing inside lubricated.



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[scooterfan]

It's a 2008 Agility City 125.
I fill 0.18 liters.

More oil will probably cause more resistance of the gears turning inside, and the excess oil will end up in the  variator via the tube that is connected between the gearbox and variator. It happened to me a few times

I think the splashing of the amount of oil as stated by Kymco should be enough to keep all bearing inside lubricated.




Thanks, I've had a close look at the breather channels on my gearbox and I actually thought an overfill should not give problems. Unfortunately I didn't take close photos which shows the breather channels. I previously didn't worry about the official specs and filled with oil right to the bottom of the filler plug. No oil ends up inside the air box - not even at speed higher than 100 Km/h.
The gearbox on my scooter definitely differs from your's - so for the time being I will stick to the overfill and see what happens.



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[scooterfan]

I fill 0.18 liters.

More oil will probably cause more resistance of the gears turning inside, and the excess oil will end up in the  variator via the tube that is connected between the gearbox and variator. It happened to me a few times

I think the splashing of the amount of oil as stated by Kymco should be enough to keep all bearing inside lubricate

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Thanks, I've had a close look at the breather channels on my gearbox and I actually thought an overfill should not give problems. Unfortunately I didn't take close photos which shows the breather channels. I previously didn't worry about the official specs and filled with oil right to the bottom of the filler plug. No oil ends up inside the air box - not even at speed higher than 100 Km/h.
The gearbox on my scooter definitely differs from your's - so for the time being I will stick to the overfill and see what happens.

[scooterfan]

Since my previous post I did a Google search about vibrations and strange noises and I stumbled across some comments which  got me slightly worried. It looks like the crankshaft- and camshaft bearings on these models might  be sub- standard:

https://advrider.com/f/threads/kymco-agility-125-blew-up-kinda-help.1033519/page-3

I will probably remove the CVT  and cooling fan covers tomorrow to see if I can find any play on the crankshaft. The scooter has done just more than 18 000km - which is way more than the distance covered on the Agility which problems at the link above.

[scooterfan]

Problem solved.
 During the weekend I had a proper look at the Variator shaft and I couldn't find any play on the shaft or Variator. A proper look at the clutch pads revealed that the three clutch pads had an uneven grip on the clutch pulley - which most probably caused the clutch to run out of balance.
So I decided to put the old clutch back in place and see what happens. This time I just clamped the clutch nut in a bench vice, got a firm grip on the clutch by hand, and managed to loosen the nut slightly by hand. After loosening the nut slightly I just clamped the clutch in a different possession in the vice bench to press the clutch spring down - obviously to prevent possible injuries.

Since the old clutch has been re-installed there is no noise and the vibrations have disappeared completely. For the time being I will just use the old clutch until I will be able to find a new OEM cluch.

Lesson learnt - don't fiddle with a 2nd hand Chinese clutch - even in good condition.

As far as the oil overfill goes - I noticed an oil leak coming from the bottom of the CVT housing. When I put the housing back a week ago the housing gasket still seemed to be fine -but at this stage I'm not sure whether the leak was caused by the overfill, or a leaking gasket.
For the time being I just drained the extra oil, and hope the leak will disappear.

[Stig / Major Tom]

Would be nice if they machined all the gear fill holes at the spot to hold the correct volume of oil!
Some of my scoots did, some not.
Had 2 Vespa owners rant at me about my not property using the gear oil "dipstick". "ALL Piaggio's have them!"
Like I'm so dumb that I couldn't see a dipstick on the gear case!
(I had to post pix - to prove this Piaggio did not have a gear dipstick )
Stig

[scooterfan]

Would be nice if they machined all the gear fill holes at the spot to hold the correct volume of oil!

Stig

True.  Compared to jeeves Agility (2008 model) my Agility's  filler hole 2009 modelis located at a lower position.  Previously I always put the scooter on the center stand and filled untill the oil started flowing backwards from the filler hole. No oil leaks - not even at speed higher than 105 km/h.

I noticed a round circle slightly lower than the filler plug at jeeves photo. Maybe that spot was where the manufacturer initially planned to install the filler hole ?


The position of the filler plug on my 2009 agility can be seen below.

[jeeves]

Problem solved.
 During the weekend I had a proper look at the Variator shaft and I couldn't find any play on the shaft or Variator. A proper look at the clutch pads revealed that the three clutch pads had an uneven grip on the clutch pulley - which most probably caused the clutch to run out of balance.
So I decided to put the old clutch back in place and see what happens. This time I just clamped the clutch nut in a bench vice, got a firm grip on the clutch by hand, and managed to loosen the nut slightly by hand. After loosening the nut slightly I just clamped the clutch in a different possession in the vice bench to press the clutch spring down - obviously to prevent possible injuries.

Since the old clutch has been re-installed there is no noise and the vibrations have disappeared completely. For the time being I will just use the old clutch until I will be able to find a new OEM cluch.

Lesson learnt - don't fiddle with a 2nd hand Chinese clutch - even in good condition.

As far as the oil overfill goes - I noticed an oil leak coming from the bottom of the CVT housing. When I put the housing back a week ago the housing gasket still seemed to be fine -but at this stage I'm not sure whether the leak was caused by the overfill, or a leaking gasket.
For the time being I just drained the extra oil, and hope the leak will disappear.

Glad you found the problem [emoji106]

I couldn't reuse the transmission gasket, had to order a new one.
The new gasket, compared to the original, also has a thin line of silicone on it.


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[scooterfan]

@ jeeves

What size wheels do you have on your Agility ?
My Agility came with 12" wheels but having a look at your pictures it looks like the wheels on your Agility might be bigger than 12" ?

I actually thought all Agility's would be exactly the same but the different gearbox on you scoot and the possibility of bigger wheels could cause a very different riding experience.