I know everyone says the stock chains are useless, but what about the sprockets? Do they also fall apart quickly or if you put a good chain on do they hold up pretty well?

I put the DID VM chain on my 02 when I bought it back in OCT. of 01. The sprockets just got replaced 2 weeks ago, could of gone futher but I went ahead and replaced for the upcoming season.

Most stock sprockets are pretty good quality, just put a good chain on before the stocker snaps and wastes those cases.

I could probably find this info in the manual, but how do you know when a chain is worn out? My stock sprocket is holding up pretty well after about 30 hours, but I do have to adjust the chain after every ride and still have a few notches left to stretch? Do I just keep adjusting 'til there is no room left or just go ahead and spring for a new one. I'm a pretty conservative rider, but I obviously don't want to cause unwanted damage.

On my old bike in the manual it tells you to measure the distance between a certain number of chain links. If it is in range it is ok, if not pitch it. This should be in the owners manual

I only had about 20 hours on it and the rear sprocket was trashed. The teeth were all curved and the chain needed adjusting after every few laps. And yes, I lubed and adjusted every time I came off the track. My sons CRF held up longer. It must have been my weight 230 lbs versus the torque combined with aluminum.

After long consideration, I bought the pricey Sidewinder ti-molly rear sprocket, went with 52T, and a ERT gold. That sprocket is amazing! The chain only needed adjusting three times and has stayed the same since.

Dentman, sounds like your chain is history. If you can hold 2 or 3 links in your hand and move them side to side with some play in there , then your chain is gone. Don't hold more than 4 though.
What I do is use the stock chain till I have to adjust it more than 2 times in 1 day. Then it is history after that. Just keep the Master Link. You ever know when you will need one of those. The sprockets should last a long time though. Just leave them on, unless you want to change the gearing with the sprockets themself.

I use to change my sprocket right away. On my CRF I have been using the stock gearing with a ERT gold chain. Everything is holding up well and showing no sign of wear. I like keeping my stock chain in my track tool bax for a spare. ASk mxjeff, it comes in handy.

I kept my chain tight every ride and I got 8 months out of my stock chain and sprockets.