Roommate’s YFZ450R won’t stay running

[Trogs_Pappy]

So my roommate left his 2020 Yamaha YFZ450R parked in our backyard in Florida for a month while he was out of town. I helped him clean it up with a hose and now it starts but shuts off after a few seconds. Battery's fine and fuel pump makes a quieter sound than usual. Could humidity mess with the electronics or fuel?

 

[like it like it]

@Trogs_Pappy It sounds like water might've gotten into a sensor or the ignition system. Do immediately check all connectors for moisture and maybe try drying out the CDI and throttle body.

 

[Frosties]

It's likely not just humidity, sitting in Florida heat and moisture can cause fuel contamination or corrosion in connectors, and a weak fuel pump might struggle to maintain pressure, causing the bike to stall.

 

[Trogs_Pappy]

Thanks for both replies. You're pointing to 2 things that likely worked together to cause the issue. We didn't think to check the CDI or throttle body for moisture, so we'll pull those this weekend and dry everything out. The fuel pump sounds weaker than usual, so we plan to test pressure and inspect the wiring harness for corrosion. If the pump struggles to maintain pressure, we'll replace it and flush the tank.

Has anyone here replaced the pump on a 2020 YFZ450R and did you use an OEM part or an aftermarket one that holds up better in humid conditions? Any advice is appreciated as we aim to have it ready for the ride meetup in early September.