About two years ago, I bought a used CRF250 dirt bike. What I didn’t realize at the time was that the fuel tank was rusted—and that little detail started a long chain of problems.
My first instinct was to recoat the tank. I bought acid and a fuel tank coating, cleaned it up, and sealed it. For a while, it worked perfectly.
But then, three months later, the bike started acting up. Turns out the manufacturer had sent me the wrong product—a polyethylene base coat. It began melting inside the tank and gumming up the entire injection system.
So, I replaced the fuel tank (this time plastic), pump, and injector. Problem solved—at least for six months.
Then one morning, the bike refused to start. Since I don’t ride it much, it often sits through long hot/cold cycles, which didn’t help. I tore it down again only to find the fuel pump was dead. Inside, I still saw traces of that melted poly from before, lodged in the pump assembly I hadn’t replaced—just cleaned. Clearly, not thoroughly enough.
So I replaced the pump, deep-cleaned everything, and put it back together. Still nothing.
Fire? Check.
Air? Check.
Fuel? Nope.
The pump didn’t even prime on startup. I had 12V up to the pump, but the moment it connected—0V. Relay clipped, pump silent.
I must have assembled and disassembled the system five or six times. Wiring looked good, continuity tested fine. I even set up a bucket fuel tank outside the bike to test it—fuel sprayed perfectly. Back in the bike? Dead.
Frustrated, I started digging deeper online and found a random forum post where someone asked: “Why do we have to cross the wires on the base plate of the pump assembly?”
Cross the wires? That clicked. The pump VCC and the fuel level sensor both connect through the base plate. Sure enough, when I checked mine, the wires were running in parallel instead of crossed.
I swapped them. Hit the start. The bike roared to life.
It’s been running flawlessly for a year now.
This whole ordeal was a powerful reminder of how experience can trick you into tunnel vision. When you’ve been working on something for a long time, it’s easy to think: “I already did that step, so it must be fine.” But that assumption can blind you to the real issue.
Sometimes, the fix isn’t about adding more effort—it’s about re-examining what you think you already know is correct.