I would like to know what engine oil i use for a gilera runner 125cc.

It is a 2 stroke there isn't any oil in your engine perse, basically your bike either runs premix fuel or it has a oil reservoir that injects oil in to the fuel mix. 2 strokes mix fuel and oil together in the crankcase, that is why 2 strokes are somewhat smokey. The oil that is injected or in the case of premix is what is used to lubricate the engines internals. So you won't be able to change the oil by draining it out of the engine block. If it has an oil reservoir you will need to top that up from time to time.

Sounds like the carb. is to small.
Or you can try changing the main jet to a larger size first

Replace spark plug Add some sea foam to fuel it is a fuel cleaner See if that helps you MOPAR KENNY

Put it on the centre stand so that it is level. On the righthand side just behind the fan cover you will see something you can screw out. It is usually black and has a grip sticking up so that you can turn it. Unscrew it, wipe it and dip it back without screwing it in. The max and min marks are clear to see. It won't take much oil if you need to top up as the sump is very small.

check for a loose wire on the relay or battery, or selionid

u are better off replacing the whole engine bec in my exsperince u will spend around £200 pound fixing that u could pick up a another gilera runner engine for £150-£200 from ebay etc

the gear box oil does not go anywhere.it helps to lubricate the gear surface.its located at the rear .pls check your carb and spark plug.if two item is o.k check your engine block is there any crack at your engine

YOU, been had.

any 2 stroke oil

Its the really big bolt on the right hand side