[noobnow]

Thinking of buying a new chain and I am a bit confused, I read that the stock chain is 520 VX3 so I am wondering whether I can use a 420/428 size chain

Amazon.co.jp: CYC Color Chain 428-130l Seal Chain Fluorescent Orange sero- 225 (' 92 '05) : Car & Bike Products

Amazon.co.jp: CYC Color Chain 428-130l Seal Chain Fluorescent Orange sero- 225 (' 92 '05) : Car & Bike Products

www.amazon.co.jp

Amazon.co.jp: CYC Color Chain 420-120L Fluorescent Orange CD90 ('98~/'87~'97): Car & Bike Products

Amazon.co.jp: CYC Color Chain 420-120L Fluorescent Orange CD90 ('98~/'87~'97): Car & Bike Products

www.amazon.co.jp

this one is a 520/120 link chain

Webike | CYCチェーン CYC CHAIN 520-120L カラーシールチェーン【ソリッドカラー】(オレンジ) CB223S(T03Z9990030OR) | チェーン 通販

should I stick with a 520 ? what difference would it make ?

also regarding sprocket Im thinking of continuing the stock size15/45, so would any sprocket work or would it have to be something KTM specific or something

thinking of taking one of these

https://item.rakuten.co.jp/hirochishop/a4104-45/

Webike | KOHKEN コーケン（旧光研電化） リアスプロケット KOHKENオリジナル 【カラーアルマイト】 CR80R 1985-1995(RK-004-47-OR) | ドリブンスプロケット・リアスプロケット 通販

42T 45T 48T 50T 52T CNC Rear Chain Sprocket For KTM 125 150 200 250 450 Motocross Enduro Racing | Wish

Buy 42T 45T 48T 50T 52T CNC Rear Chain Sprocket For KTM 125 150 200 250 450 Motocross Enduro Racing at Wish - Shopping Made Fun

www.wish.com

 

[DukeofSeven]

the 420s were pretty much only used for racing, where they also replace them all the time, because they are 'lighter'...

but they stretch a lot faster, so everything wears out a lot faster, especially on a thumper that's not being run at higher/smoother rpm all the time.

Most ppl just stick with a high quality aftermarket 520 setup. I don't know the market and suppliers in Japan, so I can't advise you there.

I'm sure one of the other guys should be along soon, to chime in. Welcome to the forum.

 

[Duke125R]

Hi! I use the lightest 520 on my 125. It's DID ERS3. It's Race chain for small cc bikes so I think it will hold up nice. But its non-O ring chain, which means it needs more care and does not hold up for long as O-ring or X-ring chains. It was about 500g lighter then original.