Sometimes the motorcycling world can be quite serendipitous. Such was the case of a special Yamaha YZ250FX and me. Back in April of 2015 I raced this machine, then an all-new model from Yamaha, at the Limestone 100 GNCC (“Confirming A Winner,” August 2015). I jelled really well with the bike and was able to pull off a win in my class, Sportsman B. After that GNCC, the same bike was used in the “Two-Stroke Versus Four-Stroke Enduro Race Test” (October 2015). In the past year and a half since that event it’s been the personal bike of AmPro’s marketing coordinator, Brian Elliott.
Brian is a great guy, but when it comes to bike maintenance he may have been better off having his three-year-old son work on this bike. The brakes were not only worn out but hardly working, with the front pads covered in fork oil from the blown fork seals. The radiators didn’t have enough coolant in them. The engine was low on oil, likely due to the seeping oil from seemingly every orifice. The tires were bald, the chain guide broken off, the air filter dirty, and he didn’t even send the bike over with a full tank of gas! When I rode the bike prior to the teardown, it fired right up but was clearly tired, feeling sluggish, and not like the bike I remembered racing through the Indiana woods.
The idea for this build was to make a two-year-old, severely abused bike come back to life and be competitive against any current 250F it came across. The revival was headed by Brad Goolsby, who has built many racebikes—not to mention being an accomplished racer himself.
The main performance mods consisted of installing a GYTR high-performance head, high-compression piston, and 450cc airboot. These mods fed power through a Rekluse Core manual clutch to the Kenda tires. We also installed a Works Connection perch and lever, which eliminated the clutch start switch. We found in doing this that the bike would only start in neutral unless the connector is cut off and both wires are spliced together, which allows the bike to start anytime the button is pressed (I found this out the night before the race in Mexico, so I had no option but to use safety wire and jump the connector then put electrical tape over the bare wire).
Since my nine-to-five job is in a fabrication shop, I was asked to help with the build. I lightened up the flywheel by 3 ounces on the lathe and was able to weld the broken chain guide mount back on for the new TM Designworks unit. The leaky fork and shock were sent out to Factory Connection for a much-needed rebuild, as well as some special AmPro spec’d valving. Ride Engineering took care of the triple clamps with new 22mm-offset units, which held a plethora of trick parts from ProTaper and Works Connection. Being that we were turning this into a full-on AmPro race replica bike, we installed a larger IMS fuel tank with a dry-break, Cycra Powerflow Plastics Kit to keep the bike feeling slim (these shrouds help) and topped it off with AmPro graphics from StukMX.
Since this bike was built for the tight woods of GNCC racing and we are on the West Coast, we figured what better place to test its tight racing ability than at the 2016 Tecate Enduro, which is known for its extremely tight and challenging trails. But the bike’s arrival and the event’s date squeezed our timeline past the comfort point. From orders not showing up on time to finding last-minute broken parts, it seemed like the bike didn’t want to go to the race. But Brad was able to pull off the impossible. In fact, I was at his house installing the graphics and final touches at 11 p.m. the night before leaving for Mexico. Although charging into special test number one is not the recommended way to break in a racebike, it was the only option we had.
Admittedly, as I exited the first turn of the race and let the little 250FX scream, I was a little underwhelmed with the power. But in my head I knew the bike was super fresh and figured it would open up as it broke in. As soon as it entered the tight trails, it became clear that this bike’s suspension was a perfect fit for the race; it was the ideal combination of supple and firm, holding itself up in the stroke and soaking up the smaller bumps but still remaining quite progressive when large G-outs appeared out of nowhere. When it came to leaning into turns the bike felt at home and planted all the way through the never-ending corners and switchbacks of Tecate.
As the first test came to an end, the engine was beginning to free up and become more powerful. Even revving the engine in the pit, I could tell that everything was breaking in and it was getting more responsive. But I also noticed there was engine oil weeping out of many seals on the engine and the bike was a tad low on oil. I didn’t have much time to investigate, so I added some oil and was on my way to start loop two.
The second loop consisted of more flowy trails where I could really open the bike up; it was then I realized how fast it was. From the bottom-end to the top, this engine puts out solid power everywhere without falling off too early or having a dead spot. In the tight, technical trails it had good chugging ability for a 250F when being lugged, only stalling one time all day. At the end of loop two I was beginning to smell oil, so as soon as I got to the pits, I checked the oil. Yet again it was a tad low, and once again I topped it off.
The third loop was a great mix of fast-paced trails and a very tight, rocky canyon. Despite not having a stabilizer, the FX never got headshake or deflected in rock gardens—always remaining plush and predictable. At the finish, I was able to pull off second place in the Open Expert class and eighth overall out of 275 entrants. After checking out the bike, it became clear where the oil was coming from. When the GYTR airboot is installed, there is no longer a place in the boot for the crankcase breather to mount, so in the heat of getting the bike together, it was overlooked and plugged off instead of being routed to a proper vent location. This left nowhere for the crankcase pressure to go, so instead of venting out the breather, it was pushing pressure and oil out of certain engine seals. Oops! Once back in the States and cleaned up, the line was routed correctly and we never had an issue again.
After racing this bike for the second time, and having such a good track record with it, the YZ250FX has cemented itself into my mind as the 250F bike to beat when it comes to off-road racing. I was sad to see this bike go, and as I gave it back to its rightful owner, I lectured him on proper maintenance (conveniently ignoring the fact that we’d created a problem of our own with our rush to build the bike). I also informed him that this would not be my last race on my long-lost brother.