STROKER 2.0mm

440cc’s. Works only with stock Yamaha Piston.

Awesome increase in low end and midrange power.

Excellent for long sandy tracks, with more torque than a CRF!

The perfect choice for woods riders or just someone looking for the ultimate in quick-revving power. We stroke your stock crank assembly, and modify your new OEM piston.

INCLUDES: Work done on your crank and piston.

REQUIRES: Send a new Yamaha OEM piston for modification.  Send in your crank for modification.  Download our Stroker Booklet for details.

RECOMMENDATIONS: For engines with over 200 hours of use, we recommend replacing the rod assembly.

16091 Y STROKE YZF426 2MM W PISTON MODS -- $400.00 CLICK TO APPROVE I am shipping my crank to Powroll for modification. I have read the General Product Info Page. Quantity

YZF & WR 400

Powroll doesn't sell these parts - order from your Yamaha dealer.

These first-generation F's can be easily upgraded to 426cc with stock Yamaha parts -- or to 440cc's with the parts listed, plus our 2.0mm stroker listed above.

One weak point on the 400 is the smaller piston pin.  Upgrading to the 426 parts gives your engine better reliability for the same (or cheaper) prices than purchasing these parts aftermarket.

You can have your 400 cylinder bored and re-nikasiled, but this process typically costs more than the $250 you'd pay for a new 426 cylinder!

To rebuild your 400 to a 426, you will need to purchase the following from your Yamaha Dealer, or online from Yamaha of Troy:

Your 400 crank will need to be rebuilt with the new 426 rod and needle assembly.  You can have a local shop do it, or order our 440cc kit above, and we'll take these parts and make your 400 a 440!