oil question

I will be changing coolant and oil in my Gpz, I've always been happy with shell rotella dino oil, but in this case the bike has 98k kilometers, and after a refresh with new rings and such around 12k ago the previous owner started using amsoil. with a liquid cooled bike will the full synthetic really help much? what oil do you guys recommend I use? if the amsoil is really worth it I have a rep at work, but if its not needed I'd rather stick with what I know and like.

The Amsoil is a good choice if you plan to run it for an extended change interval, and considering the price you will have to in order to get your money's worth. Whether or not a high buck synthetic protects your engine better is a question of much debate. Most agree that it will under extreme temperature conditions, but as you say a water cooled engine shouldn't have those extremes like an air cooled engine might.

Personally I think you will be just fine switching over to Rotella. One caveat though: the new CK-4 formula Rotella is not as proven as the older CJ-4 formula, with the never version having reduced zinc and phosphorus. You might want to hedge your bet and grab a few gallons of the older formula if you can get your hands on some.

dumb question, but how can I tell if its the old or new? does the semi synth rotella still have the zddp?

9am53 wrote: dumb question, but how can I tell if its the old or new? does the semi synth rotella still have the zddp?

All motor oils have ZDDP, it's just a matter of how much.

You can tell the new formula vs the old by looking at the certification level on the container. Since posting my comments earlier I found a link that shows that the CK-4 version Rotella still has a reasonable amount of ZDDP so all should be okay (I think).

I would use the Amsoil .

why is that?

Because of marketing or maybe he sells the stuff.

If I had a ZX900, I would use a good quality motorcycle specific oil. I think Mobil 1 4T is supposed to be a good one.