[1999GZ250]

Originally Posted by wacio

Replace oil and check air cleaner. Let oil out of air box. Checking for loose fasteners is good idea too.

Also the big bore kit is just a waste of time. This bike is never going to be fast - and not intended to. It may become much less reliable though. One of the weak points of GZ250 is head - seizing valve stems and dropping seats are common already - and may get much worse if pushed hard.

Keep it below 60mph and it will last. Going past that is something this engine hates.

Noted thanks.