if you want it to last then change it every 5000 miles. i do mine every time i change engine oil every 5000.
at 600 miles that is the break in period and most of the wear is in that 600 miles so they want to change to get ride of that lube and metal.
they think that if you use good lube that it will still be good in 20,000 miles.
of coarse that is probably for normal driving and if you drive in heat or very humid area's or dusty area's. change sooner. lol
it's like herman change sooner.
the early rIII's had a drain with a magnet and if you didn't torque it it would break off and leave 1/2 in the final drive.
in the early's it only took a small amount so really cheap.
Having now gone through two final drives on one bike, I can't agree with @TURBO200R4 more. It's very cheap insurance.
I just changed it on the 3R and forget exactly, but the torque setting on that drain bolt is very low, like 15 Nm. Get a torque wrench that goes that low (lower)- you'll need it for all kinds of things like fuel filter/pump tank gasket, etc.
Having now gone through two final drives on one bike, I can't agree with @TURBO200R4 more. It's very cheap insurance.
I just changed it on the 3R and forget exactly, but the torque setting on that drain bolt is very low, like 15 Nm. Get a torque wrench that goes that low (lower)- you'll need it for all kinds of things like fuel filter/pump tank gasket, etc.
I have been using Amzoil Severe Gear 75W-90 since I purchased my Rocket. If I couldn't get it, I would use any quality synthetic 75W-90 gear oil. I change the oil whenever I replace my rear tire (and lube the final drive splines).