Re: just bought a gs125 engine for my adrenaline, need help with servicing

Hi there and welcome to the forum. It would be handy to have some more information such as the model of bike that you have, it's age and mileage. Did you just buy the bike? if not when did the problem start and can you think anything that may have happened to cause this problem?

My Haynes manual says that the most likely cause is worn parts due to lack of lubrication or as a result of a crash, this can only be solved by inspecting each component of the transmission for signs of wear or damage and replacing them is necessary. Another possibility is that the clutch is worn to a point where it cannot function correctly caused by either high mileage, lack of lubrication or poor clutch control, replacing the clutch plates should solve this if it is the case.

Assuming that you have the Suzuki clone (K157FMI) engine to inspect the clutch and/or replace the clutch plates you need to drain the oil and remove the right crank case cover. To access the transmission you need to remove the engine and almost completely disassemble it in which case it would probably be easier and cheaper to source a second hand engine that actually works.

If it was me I would inspect the clutch and replace the clutch plates if the looked damaged and if that didn't fix the problem get a new engine.