Im also new here. I bought a 99' tw200 this past spring and put over 3000 miles since then. I've adjusted my chain several times and its to the point where I cant adjust it any tighter. Im assuming Ive stretched the chain and wore the sprockets. I have no idea what type of sprockets or chain I would need to replace it.
The Yamaha sprockets are very good quality. If you like the stock sprocket ratio, you can order sprockets from
www.stadiumyamaha.com or many other online suppliers a lot cheaper than most dealers will sell the same parts over the counter. Google
yamaha motorcycle parts. You'll also want to order the three bolt retainers and a side cover gasket in case you need them.
93823-14149-00 SPROCKET, DRIVE (14T) $10.61
15A-25450-20-00 SPROCKET, DRIVEN (50T)$22.61
The above parts you will definately need.
90215-08160-00 WASHER, LOCK $2.92 (3 needed)
3AW-15451-03-00 GASKET, CRANKCASE COVER 1 $4.78
The above parts you'll maybe be able to reuse, but for $15 might as well have them on hand. Eventually you will need them.
You'll need size 428 chain, 122 links long, and a master link. I don't recommend the Yamaha replacement chain. You can buy a much better quality open chain for the same money elsewhere. A higher quality open chain will still require cleaning and lubing on a near daily basis.
For long life and reduced maintenance requirements I like o-ring chains. Google
428 o-ring chain. RK, EK, and DID are three brands that provide a quality o-ring chain. Expect to pay from $70 to $100+ with shipping. Money well spent considering the hassle of swapping sprockets on a TW, and the hours saved on not having to do chain maintenance you won't be doing over the next 25,000 miles. All an o-ring chain needs is washing the dirt off with a water house and a squirt of something to prevent rust every now and then. Nothing unusual to go 5000 miles or more between adjustments.