426 Compression

6 replies to this topic
  • smdonald

Posted August 30, 2007 - 04:41 PM


Hey guys. I already looked for this topic. No Luck. Does anyone know what the compression should be on an 01 426? It has a Wiseco 12.5 to 1 pistion.

I just tested it and it has around 118 PSI.

  • smdonald

Posted August 30, 2007 - 04:42 PM


Im assuming this is really low....

  • Solo

Posted August 30, 2007 - 05:22 PM


Best way to get a status of the motor is to do a leak down test. A compression test is quite subjective to things like auto-decomp or manual, engine cranking speed and number of revolutions.

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

Posted August 30, 2007 - 06:43 PM


what do i need to do a leak down test. i have a compressor and numerous other tools. do I need a leak down test gauge?

  • grayracer513

Posted August 30, 2007 - 07:30 PM


Yes, you do.

  • Solo

Posted August 31, 2007 - 10:52 AM


I have a Snap-On unit but here's a link that might help-

And HarborFreight has them-

  • yamaha racing 230

Posted September 01, 2007 - 02:58 PM


118 wow that realy low

Related Content


Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

First Hare scramble tips by dhend8

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies

Thinking about Yamaha 250... by Arctic Pride

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 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.