iangpillow

I have an older RT 180, I'm not sure what the exact date is, and it recently stopped shifting. I haven't ridden it in several years and had to do some work on the clutch and the internal shift mechanism was rusted a little bit. When I left for college my dad didn't store it properly and water got into the housing, After cleaning it all out and replacing broken parts, gaskets, old oil etc. the bike ran decently for a few days. It would randomly downshift a few times but the more I rode it the less it malfunctioned. I was riding with a friend on the back and as soon as we both were on the bike it wouldn't shift after that. When I move the pedal, it clicks and feels like it's shifting but it's as if the gears never catch. Seeing as this is an older bike and I am a much more proficient rider now I was wondering what could cause this and if it would be worth fixing or if I should scrap it and pick up a newer model. Any insight would be appreciated.