01yz426 broken timing chain

2 replies to this topic
  • gregmanderson78

Posted March 15, 2014 - 02:14 PM


I found a craigslist 2001 yz426 that has a broken timing chain. I wanted to know if these engines are interference(do the valves open far enough to interfere with the piston if timing is lost) and does this failure possibly damage the head, cylinder, or case materials.

I am fine with rebuilding it, piston, cams whatever, i just dont want to have to get any machining done or try and buy new casting parts.

Any ways to determine any of these things before buying the bike?


Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • jojo1224

Posted March 15, 2014 - 02:51 PM


They are interference engines, if the timing chain broke then expect at least bent valves but it is most likely a lot worse. If you still want to buy the bike try get it for as cheap as possible so you can make some money parting it out.

  • grayracer513

Posted March 15, 2014 - 03:19 PM


They do interfere.  If the chain is broken, and the valves are bent, it will show up immediately in a leak down test.


If that can't be done, checking the valve clearance will show greater than normal clearance if the valves are bent.

Related Content



Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  30 replies

Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.