When my set goes, I think I'll use a DID heavy duty O-ring chain and Chain Gang sprockets. I've had a Chain Gang rear sprocket on my work TTR250 for 3 chains and numerous front sprockets. Amazing.

I used 3 front sprockets in 13,000 miles but it did get a shed load of sh1t thrown at it. Now fitted with a new gold chain.

Wow, those pictures really are remarkable!!! 30k in that condition is awesome......
Any idea what brand sprocket/chain combo you'll go for? My previous bike got fitted up with a Renthal sprocket/Tsubaki gold X ring chain combo. I hardly did any miles on it so can't comment on longevity, but it seemed to have smoother running than OE (although a brand new chain will always feel better....). It did look nice however! Is there any difference in quality with say blue or red chains? Is colour simply for aesthetics???

Got a tusbaki c&s set in steel. No point in me getting alloy as there is so much grit and dirt/sand in the normal roads, never mind the trails. I'veused the same kit on the ttr and its fine, just not as pretty as renthal!

Those chain gang sprockets are tough as.

Yeah mate, they certainly are. Might be dearer than a lot of the others, and maybe heavier, but their service life is outstanding. Worth every cent imo. Probably outlast a Tenere engine! :italy::what:(Hope not...)

The only problem is they don't list anything for the XT660z, but if you cross reference with JT sprockets the rear for a 99-00 Yamaha XJ600 Diversion is the same and the front for a 95-99 Honda NX650 Dominator also the same. But I still would check with Chain Gang to be sure.