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just got 03 YZ450f last Saturday

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I am new on this board, Spent several years over on a HD board and still enjoy working on modified street bike and racing 1/4 on street night at local track. Recently, been getting back into dirt bikes. Grew up riding gravel pits/woods on 2 and 4 strokes, and several cruisers on the streets. Been getting my kids into trail riding and decided to bite the bullet and get one also. Been a long time since any real ride time in the dirt. last few bikes ridden when I was kid, RM125/ Maico 400/YZ 250 yrs ago. This 03 Yz is a bunch of fun. Want to thank the riders on here for tech., have found some posts very helpful. tnks. Got a dumb question, but here it is, The chain and sprockets look reasonable, but may swap a sprocket and was wondering why some say both sprockets and chain should be replaced at same time. Seems if the equipment is in decent order this shouldn't be necessary? Also what kind of chain: o ring or not,any reasonably priced. Not going racing, just going to beat around in fields/ and where ever we can get away with riding around. Is there a special tool when putting a new chain on required ?, or is their a home brew way to do it ?. I kept old HD user name, but in the dirt world it should say newbie. later, wheelies

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First off, welcome to TT. You've found the BEST place for information on your new steed.

To answer your question, if your chain and sprockets are still the OEM, for sure they are junk. They were junk when they left the showroom, so if they are still on the bike they are beyond junk. However, if they are aftermarket and in good shape, you should be fine. When you go to replace them, it is a good idea to replace the chain and sprockets together because if you run a stretched chain on new sprockets, your new sprockets will get trashed in no time. The opposite is also true if you run an new chain on worn out sprockets. So, to get the most life out of the the chain and sprockets, replace them as a set.

As far as what to get, I would buy a good O ring or better yet an X ring chain. Either of these will last a long time and resist stretching. If you are not racing (and maybe even if you are), then I would go with a good steel or stainless steel sprocket. They will last much longer than aluminum. Ironman makes a great sprocket with a 1 year gurantee. You can get Ironman sprockets here . This site is owned by TT member Sirthumpalot so you would be helping a fellow TT'er.

Hope this helps.

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Welcome. Now that you have a YZ450, you'll have to change your name to Big Wheelies. :)

Sprockets only need to be replaced if they are worn, same as a chain. They need not necessarily be replaced as a set. Hopefully, you got a manual with the bike. In the manual, there is some detail about how to tell when they're worn and when not. Unless you step up to the Ironman or something equally light, stay with aluminum rear sprockets. Most all steel rears are just too heavy. The premium O/X ring chains from Regina or DID are an investment that will definitely pay off in terms of reliability.

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