Is the 500 gearbox designed to use oil

[kiwikx500]

or once topped up to the right level should it last for a long time like in a car gearbox ? 

[kieran]

like any 2 stroke.

Transmission shouldn't lose oil.

If it does, you've got seals busted...

[gowen]

I find that if I change my oil every few rides I do not run into any problems. My steel plates tend to turn my oil greyish. But, aside from that. I'd change it every month or so depending on how you ride. I ride the hell out of my KX and have to maintain it constantly to keep it in top shape. I've changed my oil so many times that I've had to put in Helix Threads at least 10 times in the past year.

[Timbowe]

Good call Gabe. Discolouration of the oil is a sure sign for a change. Once you can notice the colour changing, there are already a lot of contaminates in there. Oil is cheap. Compared to doing up the gearbox.