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Scooters - 125 to 300 => Downtown 300 => Topic started by: Kymco Symco on April 26, 2023, 03:32:37 PM

Title: engine noise
Post by: Kymco Symco on April 26, 2023, 03:32:37 PM
bought as a non runner.....yep i know....
anyway.....starts up.....little rev and you get a sound where i thought either a gear was rattling round on a shaft or a flywheel coming loose sound.....

ripped off the engine cover on r/h and all looks good.....

any ideas ?
Title: Re: engine noise
Post by: NorWeWa on April 26, 2023, 04:07:06 PM
Not sure what you mean, "engine cover on the r/h" 
Title: Re: engine noise
Post by: Kymco Symco on April 26, 2023, 04:09:51 PM
Not sure what you mean, "engine cover on the r/h"

i thought the sound might be coming from the engine...so i took the cover off the engine which is on the right hand side of the engine....the waterpump side...
Title: Re: engine noise
Post by: NorWeWa on April 26, 2023, 04:19:46 PM
Look into the CVT. Remove the cover off the left side rear .
Title: Re: engine noise
Post by: Kymco Symco on April 26, 2023, 04:25:47 PM
Look into the CVT. Remove the cover off the left side rear .

i removed the cover....all was tight.....so removed the drive gear on left........one drive from engine.....

started engine...revved up....noise still there.....it kind of sounds like the driver gear that the starter motor turns.....only thing i can think of....
Title: Re: engine noise
Post by: NorWeWa on April 26, 2023, 04:26:42 PM
You can get a manual from off this list.  https://kymco.at/kymco_store_view/dowloads/kymco.html 

Title: Re: engine noise
Post by: Kymco Symco on April 26, 2023, 04:30:53 PM
You can get a manual from off this list.  https://kymco.at/kymco_store_view/dowloads/kymco.html

thanks...will take a look
Title: Re: engine noise
Post by: NorWeWa on April 26, 2023, 04:39:55 PM
Removing the seat and the under seat storage bin will get you a good view of the motor and starter. 
Title: Re: engine noise
Post by: Kymco Symco on April 26, 2023, 04:45:06 PM
Removing the seat and the under seat storage bin will get you a good view of the motor and starter.

already did that......all apart to get better access.....
Title: Re: engine noise
Post by: Kymco Symco on April 29, 2023, 08:21:08 AM
Bit more more earlier this morning

advice on this please ?


best guess....feels like a crankshaft bearing has failed ?

https://mega.nz/file/oU1gFAQR#VK4ms76-DhTVwA6fccDNQBoxu1Uu7C9YIGyuWa600L4
Title: Re: engine noise
Post by: NorWeWa on April 29, 2023, 03:23:59 PM
Can you feel up and down play when you apply force to the Variator, which is on the end of the crankshaft. ?
Title: Re: engine noise
Post by: Kymco Symco on April 29, 2023, 03:26:03 PM
Can you feel up and down play when you apply force to the Variator, which is on the end of the crankshaft. ?

the crankshaft seems to have end float...it can move left/right to get that noise and on r/h side it also i think can move up /down
Title: Re: engine noise
Post by: NorWeWa on April 29, 2023, 03:44:48 PM
There should be no movement. side to side or in and out. You may have identified your problem.   
Title: Re: engine noise
Post by: Kymco Symco on April 29, 2023, 05:30:02 PM
There should be no movement. side to side or in and out. You may have identified your problem.

yes....and it will involve dropping the engine out & stripping it apart
Title: Re: engine noise
Post by: NorWeWa on April 29, 2023, 06:03:46 PM
A lot of work for sure, but you learn a lot and labor is the biggest cost in rebuilding a scooter. 
Title: Re: engine noise
Post by: Iahawk on April 30, 2023, 01:40:29 PM
these motors are very easy to pull apart and rebuild. I see your 300 is built with the same architecture as my smaller 163cc. I found it easiest to remove engine still connected to rear wheel and roll the whole assembly out. Take detailed notes on what order you disassemble everything, take pictures and bag and label all the parts that go together.

The gaskets and seals are relatively inexpensive. Might be a good time to replace cam chain guides, too.

The absolute biggest pain in the whole process was scraping the old gasket material from the aluminum cases. There's no secret sauce, just time and sharp razor blades.

Reassembly is easy but I'd recommend having a shop manual for torque specs, etc.
Title: Re: engine noise
Post by: Stig / Major Tom on May 06, 2023, 07:53:03 PM
thanks...will keep that in mind....

anyone know if this is ok to use in the transmission ?


https://www.ebay.co.uk/itm/303156726718?epid=715501195&hash=item46958c8bbe:g:oAQAAOSwYB9c3UxW&amdata=enc%3AAQAIAAAA4AkolDAj0TkHduS7xNTUPMB4dpeq%2FgR4sRF1kL5%2FDCos21ddP8%2Fwe%2BrDfo1A0fDlGNDocR0fyMOu%2BYzxENSevnFSBgABWY0zyG3lOPplGUenoBuXGJ9BzYKJ4RKlqYFia6cPGgkpVDekoVkYo%2BDbf0Nd0wMBy6j4PyuqgfNKWVqeXR5G8Mx6npuDgiDzR9gDT4mqHRVBlYh%2F%2FXJxxELuLIK%2BbIgKkcujBJSWXDxFHDIy6%2BWBeyl0pirgNJFsRXE%2BfOrTzeXDjcZqh3lXFs8w77qKj%2F8aAvxkTQTiALClhRli%7Ctkp%3ABk9SR-70jqX-YQ

75W-90 should be fine.
Nothing at your local autoparts store?
Stig
Title: Re: engine noise
Post by: CROSSBOLT on July 05, 2023, 04:26:56 PM
took a few weeks to suss it out....but i finally got it running
That's nice but WHAT did you do that got it to go?
Title: Re: engine noise
Post by: CROSSBOLT on July 07, 2023, 01:46:30 PM

Oh, so sorry to hear this! Well, now you have some nice spare parts!
Title: Re: engine noise
Post by: Kymco Symco on July 30, 2023, 10:16:06 AM
That's nice but WHAT did you do that got it to go?

from time to time yes .

thanks