Until the release of Yamaha’s thoroughly overhauled ‘14 YZ250F (read about it in the 2014 Yamaha YZ250F Second Ride
), the blue brand’s 250-class motocrosser was one of the most dated in in terms of engine architecture. Still, it provided the trusty feel of a worn-in glove making it a friendly machine to stretch the throttle cable on smooth and rough motocross tracks, alike. And stretch the throttle we did, so much that the YZ needed some routine maintenance to keep it running tiptop.
Since a 250F dirt bike engine spends most of its life under heavy load at high rpm with a relatively small volume of oil (only 1.27 quarts), it’s important to keep tabs on oil service. Although the service manual calls for oil changes every 2.5 hours we stretched it to five-hour intervals by using a high-quality lubricant like Maxima’s Maxum4 Blend Oil
It features a semi-synthetic formula making it less likely to breakdown with heat and contaminants from the clutch’s fiber plates as they wear. Available in two viscosity ranges (10W-40 and 20W-50), we ran the lighter oil as it has a greater operating range in different climates. However if you plan on frequent rides in 100-plus degree summer weather it’s wise to select the heavier mixture. For the oil filter we stuck with the stock paper element, replacing it every other oil change.
Besides routine oil and air filter service the next consumable on a dirt bike are tires. We love the versatile and long-lasting performance of the OE-fitted Bridgestone M403
intermediate terrain combo so we spooned on another set. This time however, we opted for a wider 110-series rear knob. Though slightly heavier, we prefer the larger footprint and overall handling of the bigger tire. Plus it just plain looks beefier when sitting on a bike stand. Like always, the M-series tires work well on the dirt we typically encounter on SoCal motocross tracks and provide better durability than other brands we regularly lap on.
The way the rider interacts with their motorcycle is a crucial aspect of the ride. Accordingly, we aimed at mitigating arm pump and hand blisters by installing a softer pair of handlebar grips from Pro Taper. Available in two versions (soft and medium) we went with the softer Synergy Full-Waffle MX Grips
since we value a soft and cozy touch rather than outright durability. The grips are easy to apply and with a little Pro Taper Grip Glue
and along with a couple of twists of safety wire they stay in place moto after moto. They also reduce the chance of arm pump even during long rides over rough terrain and kept the palms of our hands smooth enough to trick people into thinking that we work behind a desk all-day.
Keeping the drive chain clean, lubricated and properly adjusted is a key factor in extending its life. Thus we picked up a couple cans of degreaser and chain lube, again from Maxima. As its name implies, the Clean Up Multi-Purpose Degreaser can be used to remove gunk from virtually any component of the motorcycle with minimal elbow grease. It’s also non-toxic and has a pleasant fragrance. After cleaning we spray the chain with Synthetic Chain Guard
to keep the links free and in good working order.
We’ve always had favorable results with the YZ250F’s clutch. But after 42 hours of hard riding it had worn to the point that it didn’t respond until the very end of the lever’s throw, even with proper cable tension adjustment—a telltale sign that its nearing the end of its useful life. Thankfully, clutch replacement is a simple fix. Heck, if you lay the motorcycle on its left hand side the oil doesn’t have to be drained.
Although aftermarket companies sell less expensive clutch kits, in our experience some components perform best when stock. So while pricey, we sourced an OE clutch pack including frictions, steels, springs and a clutch cover gasket. However if money is tight you can measure the thickness of the steel plates and clutch springs, re-using if they are in spec.
Aside from a couple metric sockets and a ratchet, all that's needed is recording the order of the 11 friction and 10 steel plates. It’s also important to pre-soak the new friction plates in oil so they are lubricated when the engine is first started upon re-assembly. Besides those tips, installation is literally plug-and-play easy.
All told, we clocked 45 hours on our YZ during this past riding season. If we had held on to it longer we would have had to replace the drive chain and sprockets as well as both front and rear brake pads. Aside from those components and of course routine suspension service, it performed very much like new and still felt fresh—something that we can’t say the same about on other brand’s 250Fs when they accumulate that type of hard riding time.