At Dirt Bike Test we take bike testing serious. And we go the extra steps to stay on top of the curve and pass the information we have onto you. Learning all the time. So when Yamaha agreed to let us keep the 2015 YZ250FX and 2015 WR250F for a year, we rode them like we owned them intending to put 100-plus hours on each. We got really close. Ninety nine on the FX and approximately 125 on the WR. Both bikes were raced, trial ridden, used for course set-up at events and generally just having a fun time riding.
The captions on the photos below will give you the details but the plain and simple fact is that Yamaha 250cc four-stroke racer is extremely durable and we have nothing but high praise for the condition it was in. Even after some abusive conditions. After all that riding and racing the measurements listed below will give you an indication of how good of shape some of the wear items were in.
The only part that we felt really needed to be replaced after 100-hours was the rod and wrist pin even though it was not quite out of spec just yet, it felt looser than we like. The piston, ring, cylinder and valves were all in the middle of the range when measured and they looked just as good. In reality, since the engine was all apart, a smart owner would go ahead and replace most of the wear items. Had we not disassembled the head for inspection, after seeing it there is really no reason to touch the valves aside from a clean up.
Inside the bottom end and transmission the gears were pristine. It appeared some debris had made a trip through the oil pump but there was no loss of pressure or aftereffects from this. Even the clutch basket looked great with very little wear on it’s fingers.
The chassis, like most aluminum framed bikes was in excellent condition and had no signs of stretching nor were any cracks visible. We did not pull the suspension apart as it had just been serviced before the 24-Hour and everything looked fine, we just replaced the fork seals as preventative while doing a slight revalve for the smaller riders who would be racing the bike. The seals on the bearings in the headset, swingarm and suspension were all in great shape and the grease inside still present and in good shape. This after a year of pressure washing too. In reality any of the chassis damage was purely cosmetic and with a set of new plastic this bike would be ready for another 100-hours and looking good doing it.
3) Cylinder Bore: 77.000 mm (Spec = 77.000 – 77.010mm)
4) Piston Ring End Gap: 0.15mm (Spec = 0.15mm – 0.25mm)
Our bikes spent a year getting used in most every environment we could put it through. We have only positive things to say about the bike from a durability standpoint which is great since that is a big concern for riders as soon as they are sold on the performance. The FX as a racer and the WR more as a trail bike positions Yamaha right there with KTM in this competitive off-road arena. Getting 100 hard hours out of a 250F speaks volumes about the build of the bikes and we are glad we go to do this.
If you have any specific questions about the our Yamaha YZ or WR 250FXs, ask away in the comments and we will do our best to answer the good ones.