RS50 gearbox problem?

Hi,

So recently on my 2007 RS50 new shape, aprilia rs50....

The gearbox is giving me trouble.





For example, when moving down gear it can sometimes be very loud clunking noise.



Also just recently, it will sometimes just not find gear, i have to roll it foward ad back for it to change up or down, but seems to be fine when moving?



What would you think it is, worn cogs in the gear box???



Also will it be expensive???



Is it worth selling the bike!?
Please help.

Thanks!



I didn't find the right solution from the Internet.



References:
 www.scootershack.co.uk/threads/rs50-gearbox-problem.21129/


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