02 YZ 125 chain/sprocket/ needle question?

[barryreese]

Im fixin to purchase a new 02 YZ 125 and have a couple of questions. If I put a 51 tooth sprocket on the bike how much bigger of a chain will I need? I think 520x112 is stock. Will a 520x114 work or will it be to small or to big? Also should I go with an aluminum sprocket or a steel sprocket? Cost is an issue.

Last question, would my Yamaha dealer be the quickest way of obtaining the European model needle everybody reccomends?

 

[MXP1MP]

First off the chain is 116 links and if you go two teeth bigger you won't need a new chain but it require adjusting the chain adjuster blocks all the way in. and after that its a tight fit. So yes a new chain is required and it better be a 120 link cause after the new sprockets are installed its like 117 links are needed. The needle is not the euro spec needle is just a special needle yamaha makes you can order threw the dealer. You might have to press the issue alittle to get it but it can be gotten. I would go with aluminum sprockets cause steel weighs alot more like 2 lbs more.

 

[barryreese]

Thanks for the info but will a 118 link chain work better than a 120 link?

 

[whyzee]

Barry,
A little advice...Buy the bike before the chain...I know this goes against everything we know as humans, but, ... Once you own the bike, ride it, you may find that the sprocket gearing actually works out ok!? Again, I know this may seem like the wrong sequence in the whole purchase a chain and modify it with a new bike, but what do I know? :think

 

[spy-yamaha]

get a new chain add a 51 rear and ull have to check ur pants after u ride.

 

[whyz]

Just like whyzee125 said:) get the bike.
Yours might be different than everyone else's and might not have to gear down. For my 01yz,, I thought it didn't have any bottom according to what i've understood and read everywhere. But I believe mine has more bottom end than any of 02's that i've seen(stock)or 01's for that matter. Alot of people that i have talked to had to go 2 bigger on the rear but if anything im going to go 1 tooth smaller on the rear.:cool:
See Ya.

 

[MX145]

Barry,
When you are making the purchase with the dealership tell them that you want a 51 T sprocket installed and a new chain. DID ERT520 Golds work great. That way everything is new and will break in together. It is not recommended to change just sprockets / chain without changing the other. You will also then have spares to put on when you decide to sell the bike.

Yes you can ride the bike with the stock setup, but the sprocket/chain upgrade I would recommend as the first to do along with the handlebars. So why worry about getting the cash later and the hassle...... Get it thrown in the deal at a reduced price or at best for free !!