Going to look at a Gas Gas 125 05 for my son to start trials, not really sure what to look for, any information would be helpful. Also were they a good/bad bike to start with. Thanks

I'll avoid the usual things to check and stick to specifics. The Gearbox is different to any other make so make sure it operates normally. Any excess movement could mean a strip down and rebuild or new parts. The Airbox is designed to let water/mud though and out the bottom so don't be worried by a little dirt inside it but check the removable "step" is there above the air filter. This stops it getting drenched by anything coming though the inlet. Check the back of the Aluminium tank to make sure the airbox screws haven't made a hole in it. The engine should rev to heaven and beyond once it's warm and watch for any signs of overheating. The thermostat should be on one of the pipe's on the 05 so it isn't as bad as the later ones to change but it might be a sign of problems later. Check the exhaust mounts as well, the 05 had a steel mid box so isn't as prone to breaking them but the back detachable one still breaks occasionally. The rest is pretty standard. Bearings, both wheel and shock need to be checked. Check the frame over shocks etc.

I'll avoid the usual things to check and stick to specifics. The Gearbox is different to any other make so make sure it operates normally. Any excess movement could mean a strip down and rebuild or new parts. The Airbox is designed to let water/mud though and out the bottom so don't be worried by a little dirt inside it but check the removable "step" is there above the air filter. This stops it getting drenched by anything coming though the inlet. Check the back of the Aluminium tank to make sure the airbox screws haven't made a hole in it. The engine should rev to heaven and beyond once it's warm and watch for any signs of overheating. The thermostat should be on one of the pipe's on the 05 so it isn't as bad as the later ones to change but it might be a sign of problems later. Check the exhaust mounts as well, the 05 had a steel mid box so isn't as prone to breaking them but the back detachable one still breaks occasionally. The rest is pretty standard. Bearings, both wheel and shock need to be checked. Check the frame over shocks etc.

Many thanks for that, I'll bear that in mind when looking. Someone had told me that these bikes can be prone to main bearing failures, have you heard of this ?

Not seen any beyond wear and tear to be honest. Another 125 make is much more prone to that type of problem. Keep it on a diet of good synthetic mix oil and you'll be ok. Check the clutch fluid type. I think 05 was when the clutch fluid changed to the LHM (green) fluid. The lid of the clutch reservoir will be green in colour instead of black. If it has metal covers just open it up and check.

Edited June 15, 200818 yr by Telecat